Written by: Thomas Manion
Disclosure:
This project would not be possible without the incredible program written by astrophysicist and specialty coffee brewing enthusiast, J. Gagne, at https://coffeeadastra.com. Much of his original source code, designed to understand the effects of particle size distribution on coffee taste, was used in the following experiment and can be found at: https://github.com/jgagneastro/coffeegrindsize. Supplementary code adapts data collected by his coffee grind size app, stored in .csv (comma separated values) files, into a readable form for multiple grind settings.
Abstract
Recent variability in tasting notes during cupping of brewed coffee lead our team at Flight Coffee Co. Roasting Lab in Bedford, New Hampshire to suspect our Mahlkonig EK-43 Coffee Grinder needed an adjustment. This suspicion was verified using an open source program (discussed and linked in Disclosure). Subsequent burr adjustments made to the Mahlkonig EK-43 significantly improved the grinder's performance and our team's ability to achieve expected and consistent flavor profiles. A secondary portion of this study involved measurement of grind size at each EK-43 grind setting in an effort to compare these settings with settings of different grinders. The would help our team better support customers with different grinders who would like to improve extraction levels and flavor of their coffee. However, the EK-43's current configuration complicated this effort and new burrs will likely be needed to achieve precision in cross-product grind-size comparison.
1 Introduction
Since this is a lengthy blog, I will bold significant findings in each section to skim.
Over time a primary problem grinders face is burrs dulling and/or becoming misaligned as several thousands of pounds of coffee pass through them in commercial settings. Grinders ideally produce a mass of single-size particles at some grind setting. Different burr designs aid or hinder this goal. All burr designs will produce a range of particle sizes, some larger and some smaller than the desired size. Quality burr designs and ongoing maintenance aims to minimize variability outside the desired size range. Greater variability can result in poorly or "variably” extracted coffee, even with all other brew parameters carefully controlled and replicated. Variable-extraction in this context means at the same grind setting the coffee tastes different brew-to-brew. Unfortunately this perception is typically only accounted for anecdotally over time as the grinder ages, and can be influenced by many factors. Typically, data is rarely collected over time to quantify grinder quality changes. Another consequence, or perhaps indication, of an aging grinder is needing to adjust the grind setting finer or coarser to achieve similar brew times.
Different coffee particle sizes have different extractable surfaces areas, so a larger variation in size allows larger variation in extraction rate at any point within the coffee slurry. Our Mahlkonig EK-43 grinder, manufactured Aug 2015, exhibited not only a variable flavor profile in brewed coffee but also a seemingly noticeable spread in the grind size to the naked eye.
This project aimed to quantify whether our Mahlkonig EK-43 needed realignment and if so how beneficial the alignment was after completion.
A program called coffeegrindsize[1] was used to analyze a grind sample and calculate the average diameter and average surface area, as well as the standard deviation to 1σ left and right of the average. Supplementary Python code[5] was written to expand on the data output from coffeegrindsize which is stored in .csv files to collate many different grind settings. Analyzing the grinder in this way made possible calculating the grinder's setting-change linearity. Ideally this linearity approaches 1 (R^2=1) as the only adjustment is the movement of the two burrs with respect to each other. A strong linear fit with minimal variation could allow comparing two grinders by finding, quantitatively, what setting on a test grinder matches the size of our known setting. Additional code is in development to automate grinder-to-grinder correlation in this way.
Upon initial inspection the burrs were misaligned slightly both axially and radially. The burrs were also notably dull, and should likely be changed sometime soon. Another round of tests will follow if that occurs. After shimming and aligning the faceplate-side burrs using the method described in Barista Hustle's video[4] there was a noticeable improvement in grind pass-through time (less time for residuals to exit the grinding chamber), a seeming improvement in the naked-eye appearance of ground coffee's size uniformity, as well as a qualitative improvement in flavor. Re-taking data post-adjustment shows improvements in both grind quality and grind-setting change linearity. However, given the large spread in grind size distribution, it is unlikely the parameters of the linear fit model can adequately describe particle-size in a grinder-to-grinder comparison to a level more useful than trial-and-error.
2 Methodology
11 grind samples of a few grams each were placed into individual cupping bowls. The EK-43 was set to grind setting 1, a purge mass was run through, then the sample was run through and re-collected in the cupping bowl. The coffee was then stirred with a spoon to homogenize the grinds in the cupping bowl. The EK-43 was adjusted to setting two, a purge sample was run through at this new setting, then the sample was run through and re-collected in the cupping bowl. This procedure was repeated for each major grind setting (1-11) with several vigorous knocks on the knock-arm between samples to help purge any coffee grounds from the previous setting. The samples are shown below in Figure 1.
Sprinkling the coffee by hand consistently provided more evenly distributed coffee particles on the paper and fewer clumps caused by static, an example image is shown in Figure 2.
Each image was uploaded into coffeegrindsize and processed following the guide found in J. Gagne's user manual[3] with careful consideration to remove clumps from the data set, shown in Figure 3. Pre-adjustment data was processed four times because the coffee was not distributed on the paper as effectively in this first round of testing as compared with post-adjustment. Each setting was fairly consistent between processing attempts even though slightly different analysis regions were used each time.
CSV files generated from coffeegrindsize were passed into the supplementary code and processed. Each grind setting's average diameter and 2D surface area was calculated and stored in arrays as well the 1σ standard deviation from the average. The standard deviation is calculated internally in coffeegrindsize[2] after simulating cumulative density functions left and right of the average value. This section was taken directly from J. Gagne's source code and adapted to work with the supplemental code. The standard deviation values are plotted as error bars above and below the average, as shown in Figure 5 below. Rather than display skewness and/or kurtosis for each grind setting the higher-value deviation is labeled green to show whether fines or boulder production dominates for a particular grind setting.
Once all settings were analyzed the Python module Scipy.curve_fit[6] was used to calculate a linear regression through these average values. The parameters follow the general form:
Grind Size = A*grindSetting + B
Slope (A) |
Intercept (B) [mm] |
R^2 |
|
Pre-Adjustment |
.089 +/- .041 |
.26 +/- .006 |
.96 |
Post-Adjustment |
.068 +/- .022 |
.31 +/- .0032 |
.98 |
Table 1: Linear regression parameters |
The average values and linear regression were plotted against grind setting, shown below in Figures 4 and 5.
4 Results Analysis
An additional factor indicating the grinder needed adjustment was an audible skipping sound if the burrs were made to touch just below grind setting one. The burrs should not touch to begin with, and if they do should produce a continuous rubbing sound. Instead the sound indicated the burr faces were not perfectly parallel.
After adjusting and aligning the burrs a test sample was run through the grinder and two observations were made. Firstly, once the primary mass of coffee was ground, the duration residual particles remained in the grinding chamber was noticeably reduced. No time was measured prior to adjustment so we are unable to quantify this change exactly. Second, when adjusting to just below grind setting one[4], the burrs made a subtle continuous rubbing sound instead of the skipping sound heard pre-adjustment.
The greatest improvements pre-adjustment and post-adjustment are noticeable in the highest and lowest grind settings shown in Figures 4 and 5. Grind settings one through four pre-adjustment show little to no grind-adjustment resolution with one through three having nearly the same value and four only slightly coarser. Grind settings two and three have the same average value yet different left and right standard deviations, perhaps indicative of the variable extraction we tasted. At the high end grind settings ten and eleven pre-adjustment have much higher average changes from their previous settings, Δ=0.12 and 0.14 respectively, as well as a much larger boulders production in setting eleven compared to post-adjustment.
Linearity also increased post-adjustment as seen by the tighter grouping in Figure 5 as well as the higher R_squared value shown in Table 1. Left and right standard deviations decreased in some grind settings but increased in others, however overall there is still more spread in grind size than anticipated.
5 Conclusion
The condition of a 2015 Mahlkonig EK-43 was tested using an open source program coffeegrindsize[1] enabling quantitative measurement of particles often too small to measure accurately or efficiently. Using data from this program it was shown with supplementary Python code[5] the grinder was in need of adjustment and alignment, confirmed by lack of adjustment resolution in lower grind settings and non-linearity of average grind sizes through the grinding range. The grinder's sub-optimal performance was also noted anecdotally during regular tastings and has, to a great extent, improved since these procedures were carried out. Coffeegrindsize also quantified grind size distribution for a particular setting further indicating the burr's condition.
This first project provided guidance how grind samples should be taken in future projects with greater precision in mind. Hopefully new burrs provide a tighter distribution in grind size to make grinder-to-grinder correlation meaningful.
If you have any comments, questions, or reflections please email me at tom@flightcoffeeco.com
6 References
[1] J Gagne’s Blog about coffeegrindsize
https://coffeeadastra.com/2019/04/07/an-app-to-measure-your-coffee-grind-size-distribution-2/
[2] Coffeegrindsize source Code
https://github.com/jgagneastro/coffeegrindsize/blob/master/coffeegrindsize.py
[3] Manual for coffeegrindsize
https://github.com/jgagneastro/coffeegrindsize/blob/master/Help/coffee_grind_size_manual.pdf
[4] Barista Hustle Alignment Video
https://www.youtube.com/watch?v=5-cf0Iack5Q
[5] My github for supplementary code
https://github.com/TopDownTom/coffeeMisc
[6] Scipy curve_fit documentation
https://docs.scipy.org/doc/scipy/reference/generated/scipy.optimize.curve_fit.html
]]>If you've ever contemplated a Flight Coffee bag while enjoying a cup of your morning brew, you may have read our sustainability statement and wondered what 60% compostable means. You have probably thought that the the tin tie and valve clearly are not compostable, but they don't make up 40% of the bag, so what's going on?
Actually, I wondered this one myself when we first ordered these bags. Fortunately, at this year's SCA Coffee Expo in Boston, I had the chance to speak with one of the VPs at the company that makes our bags and he explained the whole thing to me.
Like many more things than you may realize, the word, compostable, has a specific meaning in commerce. Just because something eventually biodegrades doesn't mean that you get to call it compostable. After all, even regular plastic biodegrades (in a few hundred years).
In order to advertise something as compostable, the material in question must meet a specific standard as defined by the American Society for Testing and Materials now known simply as the ASTM, an international standards organization. The standard in question is ASTM D6400. You can purchase the full standard from the ATSM website or you can read a summarized version here. Basically, to meet the standard (and legally call something biodegradable), the item must biodegrade within a municipal waste stream within 90 days. The test is pass/fail. Either the material fully biodegrades or it doesn't.
So, what does this mean for our bags? Well, according to the manufacturer, the bags are composed of three layers of material. Two of the three layers have fully biodegraded inside of 90 days, but the third has not. When you add the 1/3 of the bag that has not fully biodegraded to the tin tie and valve, you wind up with about 40% of the bag that does not meet the standard, hence 60% compostable.
The ironic thing is that that the three layers individually all meet the 90 day standard, but when they are fused together, something happens that retards the biodegradability of one of the layers. Furthermore, if you cut the bag up, all three layers will often meet the 90 day window, but the ASTM standard requires the bag to compost in its original form, you can't cheat by cutting it up or separating the layers.
So, what does this mean to you? Well, if you participate in a municipal composting program, the bag may not be welcome in the compost waste stream (check with your local authorities, YMMV). If however, you have a home composting program, feel free to toss our coffee bags into your compost pile. It may take a bit longer than 90 days, but our bags will fully biodegrade (not counting the valve or tin tie).
Sustainability is one of our core values. We'll continue to do what we can for the environment. Thanks for helping us try and leave the planet a little better than we found it.
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The answer, as for so many industries, is a painful, “no.”
While I like to think coffee has had a net positive impact on society, its negative impact on the environment is undeniable. Millions of acres have been cleared for the planting of coffee. This invading of ecosystems by a single foreign crop degrades land in often immeasurable ways. Native wildlife loses much of its habitat and what remains often suffers due to runoff; countless pesticides, herbicides, and fertilizers are deployed on coffee farms, frequently leeching into surrounding ecosystems where they can wreak havoc. Nitrogen-based fertilizers, for example, get into local waterways and cause eutrophication (massive oxygen-consuming algae blooms that suffocate underwater life).
Enough doom and gloom, though!
There is evidence to suggest coffee farms sequester carbon, pulling it from the atmosphere into its root systems, thus helping to reduce greenhouse gas levels within the atmosphere. Some research also suggests a positive correlation between coffee grown in shaded environments (quite often specialty grade) and the sequestering of carbon. Essentially, in supporting more diverse ecosystems than other forms of agriculture, environmentally conscious coffee producers can, at their worst, exist as lesser evils and, at best, genuinely aid damaged ecosystems.
All said, considering our separation from farming, what can we do to encourage such practices?
Simple: if you buy coffee, buy specialty. From us or others, you’re, on average, going to reduce your footprint. (It really does taste better, too)!
(Specialty coffee cherries in the process of being sorted)
Our mission is to responsibly share the world’s best coffee. Towards that end, every input matters. We, like many specialty roasters, carry coffee from producers and importers doing positive work. Operations like Brazil Daterra Farms, for example, are recognized sustainability leaders, being the first Rainforest Alliance certified and ISO 14001 certified coffee farm in Brazil. Furthermore, while other farmers we work with may not be certified Organic or Fair Trade, they are generally paid above the Fair Trade minimum and often meet -- even surpass -- traditional Organic standards.
Stepping back from farming, there are also things we can do at home! For example, our next retail bag, currently in production, is 100% renewable and 60% compostable. We also recycle what we can, giving chaff (the primary solid waste product of roasting) to farmers for use as livestock bedding. Small impact in the grand scheme of things, but it’s better than nothing!
Painful as it is, we can’t turn a blind eye. There is hope, and the sooner we act, the better!
Written by Ben Evans
Edited by Jacob Ryder
]]>Recipes:
As usual we suggest weighing your dose.
Hot Brew:
Use 1 gram of cascara for every 30 grams of hot water off the boil.
Steep for 5-7 minutes. Strain
Flash Cold Brew:
Use 1 gram of cascara for every 15 grams of hot water.
Steep for 10 minutes.
Pour over full glass of ice.
As a Syrup:
45 grams cascara tea
400 milliliters hot water
Steep for five minutes, agitate every minute
Add 3 tbsp of raw sugar
1 cap full of vanilla syrup
Let cool.
Bottle the syrup and store in the refrigerator. (7 day shelf life max)
Cascara Cold Brew:
30 grams of cascara to 360 grams of cold water
Steep 24 hours. Strain/fliter out the cascara. Enjoy!
*for extra sweetness and variation add in some of tisane syrup from above and squeeze in and add orange wedge.
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Solvent-based decaffeination can be performed directly or indirectly. In the former, solvent is applied to green coffee and washed away once decaffeination is complete. In the latter, a hot water bath is used to extract not only caffeine, but other flavor- and aroma-producing compounds. Solvent is then applied to the solution, binding to caffeine. Finally, heat is applied to remove the caffeine-laden solvent and the remaining solution is infused into the green coffee (Coffee Confidential).
Ethyl Acetate is a naturally-occurring compound found in cereal crops, alcoholic beverages, and more. Among other things, it is used as a “solvent in the [manufacturing] of modified hop extract and decaffeinated tea or coffee” (PubChem). An FDA-approved process, sugarcane-derived Natural Ethyl Acetate direct decaffeination maintains wonderfully the flavors and aromas of coffee while safely and effectively removing caffeine.
To begin, green coffee is bathed in steam, removing the silver skin of the seeds. A hot water bath follows, further swelling and softening the coffee. In adding moisture, the coffee becomes more receptive to solvents and the hydrolysis of caffeine begins.
Hydrolysis: “a chemical reaction in which water is used to break down a compound; this is achieved by breaking a covalent bond in the compound by inserting a water molecule across the bond” (Northwestern University). In the case of coffee, this bond is between caffeine and salts of chlorogenic acid (InterAmerican Coffee).
Now receptive to the Ethyl Acetate, multiple circulations of the solvent are performed until 97% of caffeine is stripped from the seeds. After, the coffee is again bathed in steam, this time removing the Ethyl Acetate. What little solvent remains (less than 5 parts per million) is removed in roasting (InterAmerican Coffee).
Finally, the coffee is dried to remove added moisture, returning the green coffee to, approximately, its original moisture content (10% to 12%) (InterAmerican Coffee). The end result: decaf that tastes like true specialty coffee!
Next week: non-solvent based processes!
...
Jacob Ryder
I represented Flight at Coffee Fest Baltimore (March 16 - 18), both as an attendant and a competitor. Here are a few highlights from the show!
The Baltimore Convention Center.
The trade show.
America's Best Cold Brew
We placed second in the America’s Best Cold Brew Competition with our nitrogen-infused Ethiopia Amaro Gayo! A natural-process coffee with wonderful berry notes, nitrogenation added a creaminess that turned the cold brew into something reminiscent of ice-cream!
The competition was fierce and we're honored to have received second. Congratulations to the other winners and a big thanks to all who supported us! I was amazed at the variety of flavors present. Fruity, spicy, liquor-esque -- all products of terroir and processing!
We're fortunate to work in such a diverse and collaborative industry -- it makes us strong!
...
Jacob Ryder
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New coffees are always exciting and I have decided to go back to buying in smaller lots so we can have more fun with new and flavorful coffees at more regular intervals. We have three new coffees in house right now and two of them have become my coffee darlings because of their complexity and absolute taste of place!
First is an offering from Tanzania. Most coffees from Tanzania are grown along the Kenya border on the slopes of Mt Kilimanjaro. They often show many of the same prized characteristics of prized Kenyan coffees. Our Tanzania Mara AB is a powerhouse of key lime flavors. It is a very revealing cup as it begins to cool.
Next we have a new offering from Sulawesi. I secretly believe washed coffees from Sulawesi are the jewels of Indonesia. We have had past offerings from Tana Toroja and the new offering is similar to those. There is a real prominent cranberry note in this coffee and it sits more tart than sweet but for me that is what gives this coffee its intrigue.
Come by this Saturday for a free tasting on all of our coffees.
Cheers,
Claudia
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Taste is the interaction between substances and taste buds (i.e. bitter, sweet, salty, acidic, and umami).
Aroma is the smell of brewed coffee.
Flavor is a cumulative experience produced primarily by taste and aroma.
One of the most chemically complex foodstuffs, variation in sensory experience coffee-to-coffee is the product of genetics, growing conditions, processing, and so on. 2016 saw the release of the World Coffee Research Sensory Lexicon and corresponding Coffee Taster’s Flavor Wheel, products of collaborative research between World Coffee Research (WRC) and the Specialty Coffee Association (SCA) aiming to improve understanding. Feature-rich, let’s focus on the Lexicon’s flavor intensity ratings.
Our goal as roasters is transparency, such that all unique to a coffee is revealed in the cup. If accomplished, the challenge becomes communicating said uniqueness. Common methods include flavor notes and roast levels. However, if the roast is to be invisible (as is our goal) roast levels provide little value. Flavor notes, while useful, often appear illusory due to missing information and a lack of in-house perspective -- perhaps the ultra-delicate, ultra-unique flavor notes roasters pull are unrepresentative of a coffee? Thus, referencing the Lexicon and Wheel, we will now be including flavor intensity ratings as means of correcting these shortcomings.
Using our Ethiopia Amaro Gayo as an example, rankings will be implemented as follows.
A one-to-five scale will be used based on references in the Lexicon. In the Amaro, the blueberry ranks five -- incredibly prominent and near-universally identifiable. Rhubarb and strawberry rank lesser at two. The color used to represent each note is, if possible, pulled from the Wheel, which highlights one of the pair’s limitations: the list of traits is by no means exhaustive. Thus, certain notes (such as rhubarb) may not have a reference yet. We will do our best to properly represent such notes.
In making these changes we hope to provide clarity both in-house and -out. Keeping intensity in-mind will help us avoid being illusory. In turn, you will be better equipped to gauge our offerings.
Following the the WRC and SCA, our aim is for this project to be collaborative. For questions and comments, you can reach me at jacob@flightcoffeeco.com. For information regarding the Lexicon and Wheel, visit the WRC website.
...
Jacob Ryder
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Our Wholesale Mission
We work hard to pursue and provide the very best specialty coffee available and we strive to achieve sustainability and transparency in all of our relationships. The promise of transparency and education is the foundation of all our wholesale partners. Specialty coffee can be complicated but we promise to make it easy for you! All of our wholesale partners – from specialty coffee cafes to small bakeries- receive the same free training and ongoing support. All we ask is that our customers pledge to brew and prepare their coffee according to the guidelines of the Specialty Coffee Association. Don’t worry! We promise to get you there and keep you there!
Our wholesale partners pledge to us:
Flight Coffee Co’s pledge to its wholesale customers:
Wholesale customers exclusive to Flight Coffee, receive a free hard and electronic copy of our Coffee Knowledge Training Manual and Brew Guidelines Manual. Don’t pay to be trained. We promise to get you fluent and exceptional in specialty coffee.
Course Offerings:
Coffee Knowledge- From Seed to Cup
The Science of Brewing- Basic Barista Training
Fundamentals of Espresso (level 1)
Fundamentals of Espresso (level 2)
*Free of Charge to customers who exclusively serve Flight Coffee
Managing or Upgrading Equipment Selection:
We are happy to provide a list of what we find to be the best brew equipment available. Our list will include equipment top picks for each price range.
Equipment providers we trust: Espresso Parts, Seattle Coffee Gear, Prima Coffee
Our Top Equipment Picks:
Batch Brewer: Fetco or Curtis
Grinders: Mahlkoenig, Mazzer, Baratza
Espresso Machine: La Marzocco
We Are Happy to Provide Ongoing Consultation on Designing and/or Improving Bar Set up:
If you have the chance please visit our flagship café in Dover, NH. Flight Coffee Dover, now locally owned, was completely designed and launched by Flight Coffee Co. Organized planning and development of bar flow is key to a café’s success.
A successful specialty café represents and integrates its concept and brand into a space known as “behind the counter”. A hip interior is very cool but limiting; important to the customer’s experience are stellar customer service, a consistent product, efficiency in operation and flow. If the equipment behind the bar is set up and positioned properly, it will ensure your team stays in sync and this flow will create an amazing customer service experience. integrates everything the brand represents into a three-dimensional space—not just a cool interior, but great customer service, a great product, smart and efficient operations and a powerful identity brought to life through branding and innovative graphics. Everything works together to create something even bigger. Everything behind the bar is dependent and interdependent on the whole of the system.
Our Third Wave Roasting Philosophy:
The beauty of our roasting is in the nuance of our coffees. Sure we roasters like to fancy ourselves as alchemical wizards- keepers of Hermeticism and all of that, but the reality is coffee roasting is a skill akin to calligraphy or any fine art. The more you practice the more beautiful the form.
As a third wave coffee company, we seek to highlight and capture the character of our carefully chosen green coffee. It is our job to lovingly create a consistent and gentle roast cycle, accentuating what makes a particular varietal or farm exciting. Every minute the coffee is roasting is contingent upon the minute before. It is like a great sonnet or symphony and as passionate as we are about the roasting cycle’s never-ending prequel, at the end of the day, we want the roast to become transparent. We have done our job correctly if after each sip of our coffee, all that is revealed is the coffee’s uniquely crafted celebrated cup profile.
Our Storied Coffee
A really amazing cup of coffee tells a story of connection. We love a good back story. Sure brewed coffee is a sensual experience in and of itself but before it reaches the mug, that coffee traveled an intricate and exacting path. We like to call it the great coffee chain of custody. Every step is important, from the ripeness of coffee cherries when picked, to the way the coffee is milled and dried, to the way it is shipped to our roasting plant, to the way we lovingly roast it and yes right down to the way it is brewed by you, our knowledgeable wholesale partners. Due to the delicate balance of specifics, we must be vigilant – we must seek out direct and transparent relationships with coffee growing professionals throughout the world. Instead of simply labeling our coffee as “sustainable,” we have chosen to tell the whole story. We love talking about the uniqueness of each coffee. This way, we promise that each bag of Flight Coffee Co purchased was hand crafted with excellence at all stages, from cherry to cup. Directness and transparency are important to us. From day one we have been committed to buying coffee that is as closely aligned with our values as possible. We are pretty excited to have you, our wholesale partner, be part of our storied, celebrated coffees.
WHOLESALE PRICING:
$9/lb.
Lift Off Espresso | milk chocolate, and cherry*
Moonshot Espresso | chocolate nougat and caramel*
Papua New Guinea AA - Kuta | washed | blood orange and pepper
Guatemala Union Cantinil | raspberry and nougat
Decaf Brazil | Swiss Water Process | stout, chocolate
$10/lb.
Burundi FW IWCA | chocolate and red fruits
Honduras Finca El Pino | concord grape and sugarcane
Ethiopia Amaro Gayo | dry processed | blueberry, strawberry, blackberry, and rhubarb
Ethiopia Deri Kochere | floral, chocolate
$11/lb
Reserve coffee and miro-lots (especially Kenya) reside here. We find these coffees are best showcased as a marquis pour over coffee.
Notes:
*these are blends and as crops are seasonal, components of these blends will change from time to time. We do our best to match the profile. If an espresso blend changes, we are happy to come in and help you dial it in- our support is free of charge. We are strongly partnered and we want you brewing the best coffee humanly possible!
We are happy to create a house blend for you, but the same guidelines as above follow. We are trained to ensure your house blend is consistent. The coffees we may have to replace from time to time will be very similar. It is best to use fresh green and we pledge to do so! We often suggest you use a single origin coffee as your anchor batch brew for 3 months at a time. Rotating it keeps things interesting, fun and will put your on the specialty coffee map!
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Sustainability is an important concept in the specialty coffee world and I think, has equal importance to our good works and universal contracts we honor in our daily lives.
Let's look at the first definition of sustainability as it applies to specialty coffee- sustainability ensures what we (in the industry) do is not harmful in any way to our environment, ecological balance or to the farmer or community of farmers in which we strive to uplift.
A broader definition of sustainability and the one you may be surprised to read is the focal point of this announcement:
Sustainability (noun)- the ability to be sustained, supported, upheld, or confirmed.
As some of you know, my commute to Dover is a big one. One trip to the cafe, results in a 2 hour loss in my day. And as many of you may not know, I have two children at home, on whom I have waited to come into being my entire life. That two hour commute takes away a lot of time from my children. The contract I made with the universe when I became a mother is one that must be honored. Not part time. Not when I have the time. But always, first and foremost for is that which sustains me. Thus, I have made the decision to sell our Dover cafe.
The Dover cafe, otherwise known as Flight Coffee Dover will continue to operate under that name but under new ownership- the Bowers, a local Dover family. Kelly and Kristy have strong local ties to Dover and our amazingly talented and incredibly warm people. They have some big plans for the cafe and there is no doubt in my mind it is going to be a lot of fun with a lot of good works in the future. As for me? I am going to get back to focusing in on coffee as science and hiking. Lots of hiking.
Flight Coffee Co (the roasting lab and tasting room in Bedford) has always been a separate business focused on securing the top 1%-5% of the world's coffee crop, roasting it and providing it to retail, mail order, and wholesale customers. The Dover cafe will remain one of those wholesale customers, so the quality of coffee we have always provided to Dover will not change.
I want to say a sincere thank you to ALL of my cafe employees. From the Original Gangstas (my coffee kids) to our current crew (known as our friendliest staff ever) it has been an honor to have you as part of Flight Coffee Dover. I want to say a special thank you to Josh. Josh has been with me in Dover since day one and frankly, this whole thing would have been a lot harder without his unwavering support.
I also want to say thank you to the Dover community. Your community is strong and vibrant with local businesses. I tried to create a community space and I hope you continue to enjoy it. Our work with the Dover Children's Home has been one of meaning and I want to thank Rene and the all the folks there who continue to do good works.
Flight Coffee Co is about to get even better! We are going to do even more with Specialty Coffee and education. I am in love with finding unique green coffees. I am in love with the meditative aspect of roasting coffee. I am in love with coffee as connection. I am in love with coffee science. The Bedford Roasting Lab and Tasting Room helps me to "follow my bliss". The Bedford Roasting Lab and Tasting Room is minutes away from my family and my love circle- that which sustains me.
Cheers and thank you. Thank you with all my heart. May you always be honest and choose "that which sustains you".
Claudia Barrett
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So here we go...
Citric Acid is known for having a sour and fruity taste to it and found in fruits like lemons and oranges. Like all living organisms, citric acid plays an important role as a key intermediate compound in the plant's metabolic life. In green coffee, citric acid along with malic and quinic acid constitute a significant portion of coffee's total acid content and in the development of perceived acidity. During roasting, citric acid reaches a maximum at light to medium roasts, then quickly diminishes as roasting levels progress. A typical medium roast will lose about 50% of its initial citric acid concentrationand diminishes further as roasting progresses . Generally, Kenya coffee tend to have lower levels of citric acid than those of Central America, suggesting a less advanced form of plant metabolism. Think of all the wonderful citrus notes in Latin American coffees.
Acetic acid, or more commonly known as the active ingredient in vinegar, is produced during two stages of coffee processing: post-harvest fermentation and roasting. This is found in high doses of wet processed coffees. With this particular acid, there comes a point in roasting where it starts to evaporate away, so the darker you roast the beans, the more it will be diminished. In low concentrations acetic acid imparts a pleasant clean, sweet-like charateristic to coffee infusions, but can quickly become ferment-like at higher concentrations.
Quinic acid has a bitter, astringent taste. Quinic acid is the result of Chlorogenic acid being broken down during the roasting process to make Quinic and Caffeic acid. Chlorogenic acid is bitter to start with so roasting the bean is a double whammy… the bitterness is enhanced. Brewed coffee that sits on the heater will develop a quinic taste. It is best to enjoy this taste in a gin and tonic rather in your cup of coffee.
Malic acid is found in apples and gives a tart taste and leaves a lingering flavor on your tongue. It is found in the coffee plant itself so roasting does not have much effect on it. I tasted and blogged about a lot of malic apple notes in our Panama Duncan Estate coffee.
Chlorogenic acid, CQA, leaves a bitter flavor on the backside of your tongue. Robusta coffee has twice as much Chlorogenic acid, which makes sense because I knew Robusta coffee typically has twice the amount of caffeine in it as Arabica, and CQA and caffeine go hand-in-hand. This is also another reason Robusta coffee is so robust...it has a double layer of defense. CQA and caffeine are too bitter and caffeinated that pests steer clear from the plants.
Phosphoric acid has no taste but it helps you to perceive sparkling acidity. Scott Labs botanists searched for different mutations of French Mission and Mocha, Yemeni Typica, and began cross breeding them. They wanted more naturally occurring phosphoric acid in their taste profile. Phosphoric acid has no taste but it adds an amazing dancing and sparkling acidity that remains in the front and back of the taste. There is some great info on SL28 Phosphorus in a 1971 article by Cannell called "Uptake and distribution of macro-nutrients in trees of Coffea arabica L. (SL28) in Kenya as affected by seasonal climatic differences and the presence of fruits." The article says something like 95% of total tree Phosphorus uptake during ripening goes to the fruit. A large amount of Phosphorus is diverted to the fruit from other parts of the tree.
If you enjoy coffee, I highly recommend attending a cupping session to explore the various ways terroir and processing can impact the flavor profile of your cup. We cup pretty non-stop at the roasting lab. It is ground zero for our quality control. We hope to start regular cup pings at the Dover Cafe. So, you might be sitting there thinking, "what the heck is a coffee cupping?"
Coffee cupping has its roots in the coffee trade of the late 19th century. Coffee traders needed a fast way to evaluate the quality of a large number of coffee lots. Back then it was a simple matter of pass/fail. Hundreds of coffee would be lined up on a table to be slurped quickly and it was thumbs up, thumbs down. Needless to say there was very little attention paid to intricacies of the coffee's flavor.
As the 20th century progressed there became an increased interest on the subtleties of a coffee's flavor. In 1932, Ukers book, All ABout Coffee, was the first to detail a notion of the cupping ritual. Back then the coffee industry was limited to describing coffee in 17 descriptors and most were extremely basic: smooth, rich, acidy, mellow, Rio-y, musty, grassy, hidey and of course, my personal favorite- rank. The dawn of the Specialty Coffee movement in 1970, coffee cuppers began taking their inspiration from wine tasters and a coffee lexicon began to form. A language of coffee was building. Cuppers took note of a nuanced sensory experience of sampling coffee flavors.
In 1995, Ted Lingle (SCAA) wrote what is now considered the canonical text of the coffee cupping industry, The Coffee Cupper's Handbook . In this book a standardized cupping procedure is put forth and has become common practice throughout the industry. At the same time, Professor Ann Noble of UC Davis developed "The Coffee Taster's Flavor Wheel. It was derived from the Wine Taster's Flavor Wheel. There are over 850 aromatic and flavor compounds in coffee; wine has approximately 200. (WE WIN!!!!)
The innate characteristics of green coffee are the volatile aromatic oils locked within the cellular structure. It is these aromatic oils which are the core of any fine coffee's unique expression. In general terms, flavor, body, acidity create the specific taste profile for each lot of coffee. The roast will then work to highlight the latent aromas that are buried within the taste.
ON TASTE
]]>A simple saying: the longer the dwell time, the coarser the coffee.
You need to make sure that you use the appropriate setting for your brewing method because each method requires your coffee to be in contact with the water in a different way and for a different length of time, so a different size granule of coffee is required. If the coffee is ground incorrectly, the coffee will be either very thick and bitter or very thin and astringent.
Finding the right grind for each brewing method will most likely involve some experimentation to see what works best. With every brewing method there is a degree of flexibility. You can usually go a touch finer or coarser and still be within a good range. If you’re doing everything right and you find your coffee is weak (or brewing too quickly, especially for pour-over methods or espresso), try grinding a little finer (and vice versa: if your coffee is thick and taking a long time to brew, you should coarsen the grind).
Before using the coffee, try rubbing some of the grounds between your fingers so that you can ‘feel’ the grind and become acquainted with the differences in size.
And now for the shameless plug: Baratza grinders are the best in the universe!
6. Brewing Time/Dwell Time, A Little Agitation & The Beautiful Bloom
Here is where the magic happens. YOU WANT TO COAX OUT ALL OF THE WONDERFUL AROMATICS FROM THE COFFEE. The "bloom" phase of the brew sets the stage for beautiful aromatics. The bubbly effervescent of fresh roasted coffee, is a beautiful thing to behold. “Bloom” the coffee by saturating it with water for between 30 and 45 seconds. Note the bubbles as the coffee expands like foam. This is carbon dioxide escaping, The amount of time that the water is in contact with the coffee grounds is another important factor affecting the taste of your coffee.
7. The Here and After Brew
Pour it into a warmed mug or coffee cup so that it will maintain its temperature as long as possible. Brewed coffee begins to lose its optimal taste moments after brewing so only brew as much coffee as will be consumed immediately. If it will be a few minutes before it will be served, the temperature should be maintained at 180 – 185 degrees Fahrenheit. It should never be left on an electric burner for longer than 15 minutes because it will begin to develop a burned taste. If the coffee is not to be served immediately after brewing, it should be poured into a warmed, insulated thermos and used within the next 45 minutes.
Never reheat your coffee.
8. Enjoy Your Coffee!
Coffee sweetens as it cools! Take your time, sipping and enjoying. Remember this: lovely coffee is a total pleasure trip! Enjoy the ride and experience the cup!
A really amazing cup of coffee tells a story of connection. At Flight Coffee Co., we love a good back story. Sure brewed coffee is a sensual experience in and of itself but before it reaches the mug, that coffee traveled an intricate and exacting path. We like to call it the great coffee chain of custody. Every step is important, from the ripeness of coffee cherries when picked, to the way the beans are milled and dried, to the way it is shipped to our roasting plant, to the way we lovingly roast it and yes right down to the way it is brewed by you, our knowledgeable customers.
Due to the delicate balance of specifics, we must be vigilant – we must seek out direct and transparent relationships with coffee growing professionals throughout the world. Instead of simply labeling our coffee as “sustainable,” we have chosen to tell the whole story. We love talking about the uniqueness of each coffee. This way, we promise that each bag of Flight Coffee purchased was hand crafted with excellence at all stages, from cherry to cup. Directness and transparency are important to us. From day one we have been committed to buying coffee that is as closely aligned with our values as possible.
As a roaster, I seek to highlight and capture the character of our carefully chosen green coffee. It is my job to lovingly create a consistent and gentle roast cycle, accentuating what makes a particular varietal or farm exciting. Every minute the coffee is roasting is contingent upon the minute before. It is like a great sonnet or symphony and as passionate as I am about the roasting cycle’s never-ending prequel, at the end of the day, I want the roast to become transparent. I have done my job correctly if after each sip of our coffee, all that is revealed is the coffee’s uniquely crafted celebrated cup profile. I train and teach apprentices this skill and craft. As well as the art and science of vigilant cupping. This is what we do in Bedford.
We have won many national awards; we have won many local awards as well.
Additionally, a national magazine just ranked us in the top 25 coffee roasters in the country. We have taken our rightful place among the other great third wave coffee companies. Counter Culture. Cuvee. Heart. Stumptown.
We really love what we do at the Bedford Roasting Lab and Tasting Room. We have been crushing it since 2012. Since January 1st, 2017, the Roasting Lab the sales for national mall order and wholesale are already at $800,000 and steadily climbing and accelerating. We are one of the fastest growing coffee companies in the nation.
So alas, this is who we are. This is why we will never dark roast. This is why we will never sell our craft in big gulp containers, We are Flight Coffee Co of Bedford NH
Tomorrow, I will tell you the story of our adventures into a new community and a cafe. And how we are evolving into Flight Coffee Cafe Dover. In yesterday's post, I talked about the need to increase revenue. That does not mean we are a small struggling business. As I mentioned above, transparency is so vital in specialty coffee. When I asked to increase revenue, I was asking how we could in fact increase our loyal customer base and our ongoing quest for community engagement.
The first thing we will do after Memorial Day is extend hours into the night. But first, more of our cafe story is to come tomorrow.
Cheers and many thanks as usual!
CQ
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If you’ve ever looked at Brewing Control Chart or had it tattooed on your body and have always been confused by it, or never bothered to look at it too closely, I am willing to try and parse it all out for you. You want to hit that sweet spot in the zone, otherwise the coffee which just successfully passed through the great chain of custody was just murdered in the brew.
The vintner has complete quality control up to the time of bottling - it is pretty easy to pour wine into a cup. Coffee requires that the consumer use a bit of their own craftmaship during preparation. There are a number of variables that can ultimately ruin a cup of coffee - temperature, weight, extraction time, etc.
Luckily, much of guess work in preparing a good cup of coffee has already been investigated by the Coffee Brewing Center (CBC) during the 1960's. Led by Dr. Earl Lockhart, his research has become the body of knowledge in truly understanding the physics and science behind coffee brewing. By measuring the soluble coffee flavoring content in brewed coffee relative to brew formula, the CBC was able to graphically illustrate "solubles yield" given the coffee to water ratio. This work has provided the industry with the framework in which to discuss and compare coffee quality.
It really comes down to three questions:
1) Yield = How much did you get from the grounds?
2) Strength = How much ended up in the cup?
3) Ratio = How did you get there?How the chart works
Here, 'strength' means how much of the coffee beverage is actually coffee, so 1.25 on the scale above indicates that 1.25% of what you're drinking are coffee solids dissolved in the water. 'Extraction' means what fraction of the original dry ground coffee has ended up in your cup. For example, if you start with 5 oz of ground coffee, and 1 oz dissolves during brewing, then the extraction is 1/5 or 20%. The red diagonal lines show how much coffee you started with -- for example, the line labeled 3.75oz (106 grams) means you put that much ground coffee into the brew basket. On this particular chart, the brewing formula always assumes 1/2 gal (1.9 liters) of hot water with each coffee weight.
Remember that the brew chart applies to the actual amount of water you pour over the coffee grounds. If you want to end up with 64oz of brewed beverage, you'll need to start with more water -- about 70 oz in this case. To maintain the 4oz/half gallon ratio, you would need to increase the weight of coffee to (70/64) * 4oz = 4.37 oz.
A complete brew analysis looks also at the temperature of the brew water and how long the water is in contact with the coffee, and includes assessments of how fine or coarse the coffee is ground, the bed depth of ground coffee in the brew basket, and how well the spray head is wets the grounds.
For the algebraically inclined, the calculations assume that about 1.5oz of water per oz of ground coffee will remain in the basket after brewing. So if you start with 4 oz of ground coffee, pour 1/2 gallon of hot water over it, and measure the strength to be 1300 ppm, then the extraction is just:
]]>{[64oz water - (4oz coffee x 1.5oz water/oz coffee)] x .0013}/4oz coffee ~ 19% extraction
So what exactly makes our coffees hit 90 plus and win awards? Many things, of course. The first on the list is continuing education through the Specialty Coffee Association. Coffee is a science and new elements are constantly being discovered about the drupe. What is a drupe? A drupe (or stone fruit) is an indehiscent fruit in which an outer fleshy part (exocarp, or skin; and mesocarp, or flesh) surrounds a shell (the pit, stone, or pyrene) of hardened endocarp with a seed (kernel) inside- like the coffee cherry. Yes, we get excited about botany, chemistry and agriculture here at Flight Coffee Co. Cultivars, processing, roast profiles, brew science, roasting science, water quality and so on are things we never stop learning about.
Know what else makes us so groovy? The average price per pound for our green coffee is over $4.00. Why? Because we are in constant pursuit of the sweetest and most unique crops. We secure the top 1-3% of the world's coffee crop. We seek the best green coffee because we know we want to be the very best.
Yes we are serious roasters with over 20 years of roasting experience and many certifications but even the best roaster cannot turn a two buck chuck coffee crop into a top contender. Adjusting a roast profile can never improve an average or poor quality green coffee. We start with the best green coffee and through our experience, hard work and constant vigilance we finish with the best roasted coffee.
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I have often said that morning coffee has a way of tricking us into believing we are going to have a really, REALLY productive day. Many of our to do lists are fueled by the morning cup. By contrast, our afternoon coffee is not only our reality check but it is also our repose. It reflects a time go inward, to capture the flight of whimsy and imagination. It slows us down to say there is more to the day than rushed time, it gives us pause to take a break and exist in between that tick and tock of time.
Our slow bar for our Dover cafe is in its design stage. In addition to it existing to perform like the Apple Genius Bar for coffee, it is a way to watch just how sensual a brewed cup of coffee can be. Have you ever watched a coffee bloom? It is such a beautiful thing to behold. The bloom really prepares the coffee for the extraction. The bloom creates the chemical reaction for coaxing all those core aromatics out of the fiber of the coffee.
We here at Flight Coffee Co are drawn to beautiful coffee things. On any given day, our slow bar could feature the barista's steady choreographed hand pouring water in a circular spiral pattern over a bed of grounds or maybe you will get to see a Vacuum Pot's unique orange orb giving birth to mahogany bubbling coffee glowing in a neon light. Smells, sounds, touch and taste are all mastered in the slow bar.
]]>The raw coffee bean—not actually a legume but the pit of a small, red fruit—contains roughly 300 volatile compounds, making it chemically well equipped to be turned into a very flavorful beverage. These aromatics, however, are locked away in the bean’s extremely dense cellular structure. Roasting the tiny, rock-hard pits transforms them in two major ways. The first change is to the aromatic compounds. Heating the beans to temperatures of around 400 degrees leads to an increase in kinetic energy—or movement—on the molecular level. As the molecules bump and collide, they rearrange themselves into new formations—some into longer and more complex chains made up of multiple molecules and others into smaller fragments.
Roasted coffee has roughly three times more aromatic compounds than raw beans, which are already relatively rich in them. The bell pepper smell of green raw beans breaks down and recedes while new aromas, perhaps of savory butter or tomato soup, come to the fore. Those varying flavor notes are determined by the raw bean, how and where it’s grown and processed, and how the roaster manages the chemical reactions. Often when a coffee tastes like, say, blueberries, it’s because the very same compounds found in the berry have been formed in the bean.
The other change is to the cellular structure, which becomes porous and brittle when previously almost impenetrably dense. You can imagine the roasted bean as a microscopic honeycomb with tiny pockets of coffee oil instead of honey. The oil contains the bulk of the coffee’s aromatic compounds, and accessing it becomes as simple as breaking open the bean. The consequence, however, is that the volatile compounds begin to oxidize and degrade. While raw coffee can be stored for months without ill effect, the roasted beans are at their peak freshness for only a matter of days, which brings us back to the original question. Remember to imbibe coffee made from fresh beans with their entire array of aromatic compounds—from dried flowers to blueberries to tomato soup—undiminished by oxidation.
]]>Bourbon: -Complex acidity, caramel like sweetness, balance- Coffee produced from the Bourbon cultivar of the Coffea Arabica tree, was named after Bourbon Island where it was first cultivated. Bourbon Island was later renamed Reunion and is located east of Madagascar in the Indian ocean. France introduced the Bourbon cultivar to Africa and Latin America, that is why it also known as French Mission. Bourbon became the second most commercialized Arabica variety after Typica. Both the Typica and Bourbon varieties of Arabica are produced in large quantities throughout the world, but are slowly being replaced by more productive and disease resistant varieties such as Caturra. Although yielding more coffee cherry than Typica, Bourbon is still considered to be very low yielding. The bean size of Bourbon is on the smaller end of the scale while its leaves are broad and verdantly green. Bourbon cherry can mature into red, yellow and orange colors depending on the particular varietal. This coffee seed is known for its complex acidity and tremendous balance.
Caturra: -citric and mild sweetness- Caturra is an Arabica cultivar discovered as a natural mutation of Bourbon. The main differences are Caturra is high yielding and the size of the Caturra trees does not reach the same heights making it a dwarf varietal. Because the Caturra tree is not ideal for Brazil growing conditions, it is now more common to Colombia, Nicaragua, and Costa Rica. Cup quality typically includes bright citric acidity, and less body and sweetness than Bourbon.
Ethiopian Heirloom: - Fruity floral, wine like- Ethiopian coffee varietals are arguably the most distinctive and best tasting coffees in the world. Over 1000 heirloom varietals are currently in production. The trees most resemble the Typica varietals that are indigenous to Yemen. The trees were eventually brought to Latin America and are believed to be the first varietal grown in the Americas. Ethiopia Heirloom varietals produce some of the most coveted flavors in the world that, depending on process. Dry process coffee are usually medium-bodied with acidic, fruity/ winy tones. Wet process coffee is light-bodied but has complex floral and citrus tones.
Gesha: - Sweet, citrus, fruit tones -Gesha is an extremely rare coffee that originated in Ethiopia. The trees grow in a very high elevation, tend to be very tall (up to 15 ft) and have beautiful, elongated seeds and leaves. In 1998, there were extreme rains that brought a plague of fungus across the coffee farms in Panama. One of the coffee farmers in the region, named Peterson was able to salvage a few varietals, one of which being the Gesha tree. The reason that the coffee is so rare is because the character of the flavor changes drastically when planted in a different area, therefore to maintain its original brilliance it is grown on the original hillside. Gesha is a buoyant coffee and has a clean sweet, fruity flavor. A very distinct bergamot-like finish is also typical in the cup profile.
Pacamara: - Citric, floral - Pacamara is a hybrid seed varietal of the Pacas and Maragogype seed strains originated in El Salvador and primarily grows there. Bean size of this varietal is very large, like its Maragogype predecessor. When grown at higher elevations, Pacamara tends to exhibit better cup quality. The flavor profile can demonstrate sweet citric notes, chocolate and floral attributes.
SL28: -intesnsely citric and fruity, very complex- A very treaured cup! A hybrid of Bourbon and heirloom Ethiopian varietals developed by the Scottish Labs (during colonial years) which did lots work on varietals in the 1930′s. Very typical of Kenya where it was introduced although there have been lots of experimental plantings in central South Amercia, by those wanting to experiment.
Typica: - clean, full body, sweet flavor- Typica is the base from which many coffee varietals are developed. The coffee trees have a conical shape with a main vertical trunk and secondary verticals that grow at a slight slant, copper colored leaves, and an extended, oval-shaped bean size. Typica coffee has a very low production, but has an excellent cup quality. Coffee Arabica Typica was the first varietal of the species discovered in the Kaffa Rainforest in Ethiopia centuries ago. A French Naval officer brought Typica tree seeds to the Americas in the 1700's.
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STORIED COFFEES
A really amazing cup of coffee tells a story of connection. At CQ COFFEE, we love a good back story. Sure brewed coffee is a sensual experience in and of itself but before it reaches the mug, that coffee traveled an intricate and exacting path. We like to call it the great coffee chain of custody. Every step is important, from the ripeness of coffee cherries when picked, to the way the beans are milled and dried, to the way it is shipped to our roasting plant, to the way we lovingly roast it and yes right down to the way it is brewed by you, our knowledgable customers. Because of the delicate balance of specifics, we must be vigilant - we must seek out direct and transparent relationships with coffee growing professionals throughout the world. Instead of simply labeling our coffee as “sustainable,” we have chosen to tell the whole story. We love talking about the uniqueness of each coffee. This way, we promise that each bag of CQ Coffee purchased was hand crafted with excellence at all stages, from cherry to cup. Directness and transparency are important to us. Since opening in February of 2012, we have been committed to buying coffee that is as closely aligned with our values as possible. We are pretty excited to have you, our customer, be part of our storied, celebrated coffees. Cheers!
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On Processing:
We sure do spend a lot of time talking about processing but it impacts the cup in a big, big way so in a coffee husk, here is what it all means...processing encompasses every step that is done at origin from hand picking the cherries at harvest time to when it when it is dried milled and readied for shipment. The seed from the coffee cherry must be removed from the fruit that surrounds it. Three common methods are commonly used: washed, semi-washed and natural.
Washed Process or wet method:
WET METHOD
The wet method makes a really clean cup of coffee that is crisp, delicate and showcases sparkling acidity.
The wet method (also called the washed method) requires the use of specific equipment and substantial quantities of water. When properly done, it ensures that the intrinsic qualities of the coffee beans are better preserved, producing a green coffee which is homogeneous and has few defective beans.
Even after careful harvesting, a certain number of partially dried and unripe cherries, as well as some stones and dirt, will be present among the ripe cherries. Usually what happens is cherries are floated in water and the ripe cherries will sink to the bottom for processing and the unripe cherries will float. (Hence the bean defect Floater) Cleaning can be done by washing the cherries in tanks filled with flowing water. Screens may also be used to improve the separation between the ripe and unripe, large and small, cherries.
After sorting and cleaning, the pulp is removed from the cherry. This operation is the key difference between the dry and the wet methods, since in the wet method the pulp of the fruit is separated from the beans before the drying stage. The pulping is done by a machine which squeezes the cherries between fixed and moving surfaces. The flesh and the skin of the fruit are left on one side and the beans, enclosed in their mucilaginous parchment covering, on the other. The clearance between the surfaces is adjusted to avoid damage to the beans. The pulping operation should also be done as soon as possible after harvesting to avoid any deterioration of the fruit which might affect the quality of the beans.
The pulped beans go on to vibrating screens which separate them from any unpulped or imperfectly pulped cherries, as well as from any large pieces of pulp that might remain. From the screens, the separated pulped beans then pass through water-washing channels where a further flotation separation takes place before they are sent to the next stage.
Because the pulping is done by mechanical means it normally leaves some residual flesh as well as the sticky mucilage adhering to the parchment surrounding the beans. This has to be completely removed to avoid contamination of the coffee beans by products resulting from the degradation of the mucilage. The newly pulped beans are placed in large fermentation tanks in which the mucilage is broken down by natural enzymes until it is dispersible, when it can be washed away. Unless the fermentation is carefully monitored, the coffee can acquire undesirable, sour flavours. For most coffees mucilage removal takes between 24 and 36 hours, depending on the temperature, thickness of the mucilage layer and concentration of the enzymes. The end of the fermentation is assessed by feel, as the parchment surrounding the beans loses its slimy texture and acquires a rougher "pebbly" feel.
When the fermentation is complete, the coffee is thoroughly washed with clean water in tanks or in special washing machines. The wet parchment coffee at this stage consists of approximately 57% moisture. To reduce the moisture to a maximum 12.5% the parchment coffee is dried either in the sun, in a mechanical dryer, or by a combination of the two. The sun-drying is done on extensive flat concrete or brick areas, known as patios, or on drying tables made of fine-mesh wire netting. The beans are laid out in a layer of 2 to 10 cm, and turned frequently to ensure even drying. Sun-drying should take from 8 to 10 days, depending upon ambient temperature and humidity. Coffee dries more quickly if raised on tables because of the upward draught of warm air. The use of hot-air drying machines becomes necessary to speed up the process in large plantations where, at the peak of the harvesting period, there might be much more coffee than can be effectively dried on the terraces. However, the process must be carefully controlled to achieve satisfactory and economical drying without any damage to quality.
After drying, the wet-processed coffee, or parchment coffee as it is commonly known, is stored and remains in this form until shortly before export.
The final stages of preparation of the coffee, known as 'curing', usually take place at a special plant just before the coffee is sold for export. The coffee is hulled, to remove the parchment, then passes through a number of cleaning, screening, sorting and grading operations which are common to both wet- and dry-processed coffee. Electronic sorting machines may be used to remove defective beans that cannot be distinguished by eye.
DRY METHOD
The dry method makes for a wild and rustic cup! Heavy body, subdued brightness and lots of jammy fruits!
The dry method (also called the natural method) is the oldest, simplest and requires little machinery.
The method involves drying the whole cherry. There are variations on how the process may be carried out, depending on the size of the plantation, the facilities available and the final quality desired. The three basic steps, cleaning, drying and hulling, are described below.
Firstly, the harvested cherries are usually sorted and cleaned, to separate the unripe, overripe and damaged cherries and to remove dirt, soil, twigs and leaves. This can be done by winnowing, which is commonly done by hand, using a large sieve. Any unwanted cherries or other material not winnowed away can be picked out from the top of the sieve. The ripe cherries can also be separated by flotation in washing channels close to the drying areas.
The coffee cherries are spread out in the sun, either on large concrete or brick patios or on matting raised to waist height on trestles. As the cherries dry, they are raked or turned by hand to ensure even drying. It may take up to 4 weeks before the cherries are dried to the 12.5% maximum moisture content, depending on the weather conditions. On larger plantations, machine-drying is sometimes used to speed up the process after the coffee has been pre-dried in the sun for a few days.
The drying operation is the most important stage of the process, since it affects the final quality of the green coffee. Coffee that has been overdried will become brittle and produce too many broken beans during hulling (broken beans are considered defective beans). Coffee that has not been dried sufficiently will be too moist and prone to rapid deterioration caused by the attack of fungi and bacteria.
The dried cherries are stored in bulk in special silos until they are sent to the mill where hulling, sorting, grading and bagging take place. All the outer layers of the dried cherry are removed in one step by the hulling machine.
The dry method is used for about 90 percent of the Arabica coffee produced in Brazil, most of the coffees produced in Ethiopia, Haiti and Paraguay, as well as for some Arabicas produced in India and Ecuador. Almost all Robustas are processed by this method. It is not practical in very rainy regions, where the humidity of the atmosphere is too high or where it rains frequently during harvesting.
Pulped Natural/Honeyed/Miel:
Pulped natural coffee can have more body and lower acidity than the washed process, and a cleaner, more uniform cup than the natural process. They are sweet and balanced.
Honey coffee is a process where some of the mucilage that covers the bean is left in it by less washing. Semi-washed coffees are dried with the mucilage clinging to the outside of the parchment. When it is well done the process generates an amazing, sweeter taste that intensifies the chocolate nutty aroma/taste of our Dota/Tarrazu. The mucilage that covers the bean is packed with sugars and that is what generates the different taste. During the drying, specially if you do it under the sun like us, the parchment will take on a slight orange color. The perfect stage of the harvest to do the honey coffee is the center of the harvest, where the coffee cherry is naturally packed with more sugars, it oozes the honey.
Like any process, leaving the honey on can spoil the taste of coffee. in traditional milling, the coffee beans have the mucilage taken off by a process of fermentation, usually about 10 hours. this process makes or breaks the quality bec can excessively ferment. In my process, we wash the mucilage off the bean with a centrifuge, as part of the milling. So we only need to set up the amount of water on the washer and voila, an amazing coffee taste comes out.
WET HULLED/SEMI WASHED:
Rustic and earthy the semi washed/wet hulled method compliments many of the unique characteristics of the prized coffees of Asia and the Pacific.