We see the proliferation in quality decaf options as similar to the low- or no-ABV movement happening in the alcoholic beverage industry, or even the now ubiquitous presence of superb plant-based alternatives. The idea here is not to create the best imitation, but the best product overall – which can sometimes be better or beyond the thing that inspired it, or even combines with it in interesting ways.
At Square Mile HQ, there’s a pot of decaf filter floating around most afternoons. While sipping, we ask: what do we want from our decaf line? A few answers: Reliably decaffeinated (we’ve started using a caffeine metre to check). Delicious, balanced, sweet–and not just “for a decaf.” And most challenging of all, full of identity and intentionality. We want to see the same breadth and specificity we offer in our full-caff coffee. Not long ago, full-caff coffee was also a nameless commodity considered interchangeable, no matter the care put into it. Our approach to decaf is tailor-made, and we continue to question and tinker with it daily.
Roasting and Brewing
We follow the same QC and profiling process with all of our decaf products as anything else we serve, which should come as no surprise. But decaf’s reputation as a compromise makes us take a little extra pride in exceeding expectations.
Any roaster will tell you that roasting decaf well takes extra care. Decaffeination tends to a) raise the moisture content and b) lower the density in comparison to the original beans. We can apply our methodology from roasting other high-moisture coffees (e.g. naturals, honeys), including a soft application of heat at the beginning. The idea here is that going too hard up front will create a big build-up of energy as the extra water absorbs the heat, making the roast difficult to control at the end. This is critical for decaf especially because that lower density makes the end of the roast even more important. After the drying phase (when water has evaporated), the remaining bean is a fragile shell, prone to burning if heated too aggressively. Though we record the Agtron Gourmet measurement of every roast to check for consistency, decaf behaves differently because of its darker starting colour, so the roasting team relies even more heavily on cupping and brewed QC.
Our Half-Caff Blend presents its own challenges as these qualities make decaf extract slower than other coffees. With any blend, we aim to match the solubility of the components so that they brew together consistently. Square Mile production roaster Gabriel Martín applied this thinking to Version 1 of Half Caff (50% Decaf Brazil Aequitas and 50% Tanzania Itumpi). Opting for a slightly lighter profile of Itumpi than what he would choose for a single origin filter helped it pair better with the slow-extracting Decaf Aequitas, creating a cohesive blend with caffeine levels measured reliably near 50%. He also compared the grind distribution of the components to ensure they behaved the same–at their final profile, they produced the same amount of fines.
Identity and Intentionality
We are actively involved with the supply chain behind our decaf–in fact, it often strengthens our existing relationships, allowing us to buy more from the same vetted partners We’ve used toll-decaffeination since 2013, allowing us to choose the green coffee lot serving as the base as well as the decaf plant and process. This requires a significant scale commitment as most decaffeination plants have a minimum run quantity of 4000 kg. The decaf process also puts a lot of pressure on the molecular structure of the beans, shortening their shelf life. For this reason, we aim to use it decaf within 3-4 months of being decaffeinated for peak flavour.
With all of this in mind, a key factor for us was finding a decaffeination plant in Europe, so that we didn’t have to limit ourselves only to coffees from specific origins, but could minimise the footprint and lead time. Our main partners are CR3 (using their CO2 process) and Coffein Compagnie (using their EA Process) . Just as we roast specifically for espresso and filter, with time we have learned how to select green lots and pair them with a decaf plant and method. One odd example: an astringent – nutty note, which may be abrasive as a single origin filter or on the cupping table, seems to pair really well with the Ethyl Acetate decaffeination process from Coffein Compagnie. Post-decaffeination, they seem to us more balanced, complementing the process in a way that feels round and sweet and less “painted” with signature EA flavours of strawberry jam or barbecue sauce.
CASE STUDY: DECAF AEQUITAS
Decaf Aequitas was years in the making. In 2022, Volcafé’s Andrew Tucker impressed us with a new project: a regional Cerrado blend with ethyl-acetate (EA) decaffeination done by Germany’s Coffein Compagnie. Its clarity and winey acidity subverted all of our expectations of decafs, naturals, and Brazilian coffees. The decaffeination had added value to the balanced but two-dimensional full caff version coffee.
This spurred a thought: could we intentionally source coffees to taste best as decaf, like we purpose-roast for filter and espresso? For 2023, we worked with Andrew to approve a regional Cerrado green lot specifically for Square Mile’s decaf purchase, involving ourselves in the process from the very beginning.
After setting the stage, in 2024 we partnered with Yuki Minami, Cerrado farmer and founder of Brazilian exporter Aequitas. Together, we selected a Catuai lot from her family farm specifically for decaffeination at Coffein, prioritising texture to complement the EA process’s subtle added acidity. Yuki typifies a new generation of Brazilian producers who meld the equity of thoughtful mechanical picking with soil restoration and cup quality. The success of this decaf purchase gave us the opportunity to work with her on a meaningful volume.
The Future of Decaf at Square Mile
Our fascination with decaf is unwavering. Over the coming year, we plan to introduce new decaf products from some of our favourite partners in Ethiopia, Mexico, and Honduras. As the demand for decaf continues to grow, we remain focused on pushing the boundaries of what it can be. This means continually refining our processes, experimenting with new methods, and collaborating with partners who share our interest. Our goal is to create lower-caff coffees that need no equivocation. They’re not an ersatz version of their caffeinated counterparts, but unique, flavorful experiences in their own right. Whether you’re a decaf drinker by choice or necessity, we aim to turn your head with a tasty and thoughtful selection.
