Scaling Quality: Sample Roasting

Tasting coffee is the foundation of any high-quality coffee sourcing company, and you can’t taste coffee unless you roast it. Different companies take different approaches to sample roasting, but the key to any approach is being able to execute it consistently. It’s impossible to build accuracy and objectivity into your cupping process if you don’t start with the right roast, so our goal is to make sure that our roasting process is as repeatable as possible.

To ensure maximum consistency, we start with the right tool for us: Ikawa roasters, which run consistent roast profiles off a digital console with precise temperature controls. The dilemma that underpins this is whether or not one size fits all: can you learn the most about coffees by tasting them all on the same profile, or do custom profiles reveal the most about a coffee’s true nature? 

For us, the answer is somewhere in between and relies on the water activity (aW) of a coffee, or the rate at which moisture moves in and out of the raw coffee seed. We believe that when tracked consistently over time, water activity readings can yield a ton of information—not just about a coffee’s shelf-life, but also about how it’ll behave when you, our customers, production-roast it. Since we have pretty tight ranges for water activity in coffees we buy, we have 3 custom profiles that we choose from based on a coffee’s water activity and moisture. 

Across roasters, we’ve noticed that a higher water activity will crack harder, carry more momentum, and generally take less energy to get to its end temperature. On the other side of that, coffees with lower water activity can tend to exotherm less when compared to coffees with higher water activity when they crack and require more energy to develop properly and get out of the roaster. So, our 3 custom profiles compensate for that range, allowing us to get the same level of development out of each coffee with consistent, slight tweaks to profile. 

With a lot of our sample roasting done at elevation, we also tweak profiles to compensate for that factor. Although Ikawa’s heating element is PID-controlled and will digitally attempt to follow the profile curve, we’ve noticed that if we use the exact same profiles at elevation, the coffees will overdevelop on the same line. To compensate, we increase the airflow during roasts and drop the final end temperature a little. Over time, we’ve gotten to a point of consistency where the roast is rarely a factor on the cupping table unless we want it to be.

These profiles aren’t and never will be set in stone. On the thankfully rare occasions where we feel like a sample roast is noticeable on the cupping table—meaning that the coffee might taste dark, light, overdeveloped, or underdeveloped, to the point of making it more difficult to assess the sample itself—we make a note to take a look at what factors might have influenced the roast and experiment with our process from there. 

For instance, water activity and moisture are usually tied closely together, but in rare instances, they differ. One time, we noticed that a coffee tasted underdeveloped, and it turned out that while it had a slightly higher water activity within our narrow acceptable range, it had a very low moisture content, which had affected the roast. From there, we made sure to adjust our protocols to swap roast profiles based on moisture within a certain range rather than basing them on water activity alone. This is just one of many examples. 

We do our best to represent the coffees that producers work hard to bring to our table and the onus is on us to guarantee that our assessments are based on the best data available. Our roasting process should never be a variable, and we work hard to make sure it isn’t. That helps us not only to bring in great coffee, but also to ensure that our producing partners get to showcase their work and put their best foot forward, even though they aren’t physically present while we’re tasting their coffee.

If you ever have any questions for us about the way your coffee is roasting, shoot us an email and we’ll be happy to share our thoughts. To see our Ikawa profiles, get in touch with your trader or hit us at info@redfoxcoffeemerchants.com.

To read a truly excellent primer by resident roastmaster Joel Edwards, click here.

Posted in Lab

Sample Roasting

 

This piece was originally published here in 2016 and shares some general principles, specifics, and best practices. To learn more about our current sample roasting program, click here

Hi folks, Joel here! I often get questions from customers about sample roasting, so I wanted to share some thoughts on our approach and the protocols we use at Red Fox.

An important part of what we do here at the lab everyday is evaluate samples, and it’s necessary for us to have protocols in place to help us accurately assess quality. Our protocols for sample roasting are designed with the goal of achieving consistent results, so that we can compare many, many samples, as accurately as possible, across days and weeks and months.

When a sample arrives here at Red Fox, we first measure its moisture content and water activity (aW). Moisture content is literally how much water is left in the coffee after it is dried. A coffee seed has a moisture content of around 60% when it’s first put out on the drying table or patio. As the coffee dries, the moisture content is brought down to 9-12%, usually over 7-21 days.

Water activity, simply stated, is a measurement of how bound that moisture is inside the coffee seed. There seems to be a relationship between how quickly a coffee has been dried and its aW. That is, coffee dried very quickly will often have a higher aW, while coffee dried more slowly will have a lower one. We pay attention to moisture content and aW because they tell us something about how a coffee was prepared and how the quality might change over time, but also because they give us clues as to how that coffee will behave in the roaster.

Higher-moisture coffees need more energy to get going and I will often introduce them at a higher temperature. (Density plays a role in this as well, but I am focusing on higher-grown, relatively dense coffees here.)

A coffee with a higher aW needs less energy during the latter part of the roast (especially going into and out of crack), while coffees with a lower aW need more energy to achieve the same line.

At Red Fox HQ, we have a two-barrel Probat sample roaster and we use a 90g charge to achieve the roast times we are looking for. For a coffee at 10% moisture content, I’ll introduce the sample at 350F on the analog temperature display, with the air fully to tray and a high flame. (For the broadest audience appeal, I’m assuming we’re all old school and don’t have any fancy thermocouples or data-loggers on our sample roasters). Once the coffee has turned yellow (lost all green shades), I’ll increase the air to drum to about three-quarters open. This happens between 3:15-3:45. At first crack (shooting for between 7:00-8:00), I will open up the air even more. If I’m working with a coffee with a higher aW, I’ll also lower the flame setting at crack. The idea is that during crack a coffee with a higher aW will really want to race once it goes from endothermic to exothermic. By increasing the air flow and lowering the flame, I’m trying to mitigate that. The opposite is true for a coffee with a low aW, where it almost acts like a heat sink and needs more energy to finish (in my case, less air to drum). I’m sure we’ve all roasted a coffee that seemingly takes no effort at all and easily follows the ‘standard line’ without abnormally big air/gas changes — that coffee was probably well-dried with solid moisture content and aW. Depending on the coffee, I’m looking for a “development time” after crack of anywhere from 1:15-1:45.

The metric we use to measure roast degree is percent weight loss or:

1 – (end weight/starting weight)

For example, a 90g charge with an end weight of 79.8g is:

1 – (79.8/90) = 0.113 or 11.3% loss

We are finding that we generally like samples to fall between 11-13% loss. Lower than this range and we start to taste grainy, cereal-like flavors (underdeveloped). Higher loss will begin to take on roasty/bitter flavors (overdeveloped). That being said, lower-moisture coffees can take a lower % loss and will take on roasty flavors faster (e.g. a coffee with 9.2% moisture could taste fine at 10.75% loss, but might start to develop roasty flavors at 13% loss). Similarly, higher-moisture coffees can take somewhat higher weight loss before showing roasty flavors and will taste underdeveloped at 10.75% loss. If you want an easy answer in the struggle between under- and overdevelopment (in sample roasting), then 11.5%-12.5% loss is almost always just right.

Note that these are standards we’ve developed at our lab on our equipment. The specific times and temperatures may not work for you, but the principles will. Even more important is creating a standard protocol, so that you can properly evaluate each sample you receive. If every sample is roasted to different standards, it will be difficult to accurately assess the quality. How many offers have been passed up because the roast was off?

Lastly, I want to mention our intentions when we sample roast. We are not necessarily looking for what the coffee will ultimately taste like as a production roast, but rather we are evaluating each coffee for sweetness, brightness, and body with clarity of flavors and whether any defects are present. This roast style is meant for cupping specifically and will not extract fully in most other brew methods.

I would love to hear your thoughts on any of this and welcome a continued discussion.

Best,
Joel
These protocols have been informed by Scott Rao’s “The Coffee Roaster’s Companion” and by roasting and cupping thousands of sample roasts. That being said, everything is impermanent and they will likely change as we refine our technique and understanding.

We’re Opening a Year-Round Lab in Oaxaca, Mexico

 

Why Mexico?

As I rode in the back of a car, looking out at the green, rolling, coffee-laden hills of Veracruz a few weeks ago during early harvest meetings, one of my hosts and new partners in the area asked me, “why do you like Mexico so much?” referring to me sourcing coffee, and now living, in Mexico. It really made me stop to think about it, especially as Red Fox is now on the cusp of opening our second origin office and cupping lab, here in Oaxaca.  

I could have easily given my stock pitch that I’ve been using the past six years working here, going on about “potential” and “opportunity,” talking about providing links and access for smallholders to a higher paying market, which is all certainly true, but it didn’t feel like the full, honest answer in that moment. So, why Mexico? 

The truth is, Mexico has something extra going on that’s just, rad. The creativity is overflowing and inspiring. There is a buzz around coffee culture here that is unique in the producing world. People love coffee here, and they consume a LOT of it. The sheer volume and year-over-year growth of specialty roasting companies and high end coffee bars across the country is staggering. Beyond coffee, Mexico has one of the most exciting culinary traditions and innovative scenes going on right now anywhere in the world. The food and drink has that special “sazón” and spice.  Coffee is part of that now more than ever. We want to be a part of that.  

Maybe one of the most key aspects of this question though, is that, being from the US, we share the same land, we are neighbors, and in this current toxic, divisive socio-political “climate” it feels right and important to build these bridges with our neighbors, and do business the right way, respecting people. Fuck walls. We want to help tear it down. That’s the truth.

It’s also true that the coffees are really, really good here. There is a lot of work happening in the field to improve quality and revive the incredible bank of genetic material that they still have in Mexico and maybe not anywhere else. But there is still so much work to do in improving lot separation and traceability, quality at farm and processing level, and making sure price premiums for quality reach the farmers. And, Mexican coffees are still largely under-represented in the high end specialty coffee marketplace. Building and investing in our office and field team here will continue to work to fill that gap.

As with anywhere that Red Fox is sourcing, we only want to be in and invest in origins where we truly add value, and where we are able to have exclusive and first-pick access to coffee from communities that can produce at the highest level. As with our sourcing work anywhere, we want to be out in front to bring those to market.

The diversity of flavors is truly astounding here. The three main producing states in the south of the country—Chiapas, Veracruz, and Oaxaca, in order of volume—are each incredibly distinct from both a cultural and supply chain perspective. We are actively working and sourcing in all three regions and will have a large range of offerings from each come May and June. Where Veracruz has higher yields and larger average farm size, it also has a culture of “cerezeros” or farmers and processors selling/buying cherry (rather than dried parchment) and centrally processing in larger volumes at wet mills. Chiapas, with its vibrant revolutionary spirit, has a strong culture of organic production and “cooperativismo” but also more recently of incorporating new processes, planting new varieties, and making efforts to combine environmentally sound, yet profitable, coffee production with protection of important biosphere reserves.  

Oaxaca is an enigma in many ways but also can produce some of the very best cups in the country. Production here is still overwhelmingly driven by original lines of Bourbon and Typica, including the unique Pluma variety in the southern coastal mountains. With 16 distinct indigenous groups/cultures alone, many of which grow coffee, the region is incredibly diverse from an environmental, climatic, and social perspective. There are so many logistical and cost-of-production challenges here but that’s what excites and drives us to get better and bring these lots to more of our roasting clients and their end consumers. These are vibrant, delicious, sweet, sessionable coffees that seem to disappear from your cup because they go down so easily.  

Our relationships are the deepest here in Oaxaca. We’ve been building up our supply chain from the farm level (producers here average 1-2 hectares) in terms of quality improvement and separations as well as price negotiations and premiums, rather than working from the exporter or co-op level down. Financing is a big challenge farmers face here and we are committed to working creatively to solve this in both the short and long term. 

Motivated by the success and growth of the past two years since opening a year-round lab and team in Peru, setting up shop here in Oaxaca gives us more access to more coffee and a bigger chance to influence production and profitability for farmers in Mexico. 

We are so excited to be a part of this unique culture. After testing the waters for the first two years, last years’ harvest volume, quality, and our ability to deliver on time showed us that this is real. Now we are fully immersed. Jump on in with us, it feels great. 

 

— Adam McClellan, Mexico Sourcing and Sales Lead