28 Feb 2021 Anaerobic coffee: the next big thing in coffee?
The coffee industry can never rest on its gilded laurels – these days savvy players keep rocking the game with a steady stream of new flavours or preparation techniques.
Craft techniques, as well as new flavour profiles and roasting styles, can elevate even the average cup of Joe — even those made at home. This new coffee trend is catching the eye of caffeine addicts and beer lovers alike: anaerobic coffee.
What is anaerobic coffee?
“During a blind tasting, there was this one coffee that was so distinct in smell and flavour, that I thought it was a defective cup,” says Maryna Gray, director of coffee for Seattle-based coffee subscription service Bean Box. “I wasn’t even sure how to describe it — I had nothing to compare it to.”
As anaerobic coffee is processed differently to showcase its punchy flavours and the bright, fresh quality of the beans, Gray says that the flavours she tasted included super-sharp tropical, as well as an interesting sour candy notes that she says echoes that of sour beers.
“It twists around your expectations of what you can get out of a cup of coffee,” she says.
The roast tends to be lighter in style, which allows sippers to taste the bean and all of its different sugars.
How is it made?
The process of making anaerobic coffee is by no means an easy one, says John Johnson, director of coffee at City of Saints Coffee Roasters based in Brooklyn. Unlike other styles of coffee, which are made using open fermentation, in which the air interacts with the beans, anaerobic coffee is made in a sealed environment.
The the coffee is placed into hermetically-sealed, stainless steel containers. Aside from yielding new, unexpected flavours, the anaerobic process provides a high level of control of the sugars, temperature, pressure, pH and time.
The flavour of the coffee fruit is concentrated in the juice, not the seeds. Coffee cherries are the fruit of the shrub and the sugars are contained in the mucilage. The concentration of sugars and flavours depends on the variety, ripeness of the fruit, and type of soil among other factors.
“The concept is very similar to processing wine. If a wine becomes too oxidized during fermentation, acetaldehyde can convert to acetic acid – and, fun fact – that particular organic acid tastes a whole lot like vinegar. In coffee, the benefits of approaching fermentation this way aren’t all that different. The CO2 rich atmosphere created by the anaerobic environment kind of just makes anything fruity or otherwise vibrant about a given coffee ‘pop’.”US coffee roaster, Travis Spear, read more
Now let’s move on to the process. First the coffee is depulped and the seeds are placed inside the fermentation tanks. The separated mucilage is then tightly packed into a gel-like consistency and added to the fermentation tank until it covers the entire parchment.
As the fermentation begins the levels of O2 diminish and the CO2 increase, creating pressure in the fermentation tank. The process lasts between 18 to 23 hours – long enough for the mucilage to be consumed, but not so long that alcohol is produced.
After 15 hours the pH needs to be constantly controlled to determine how the fermentation is progressing.
The pressure created by the CO2 allows the flavours of the coffee juices to be injected into the parchment. Once the fermentation has concluded the tanks are opened (carefully – due to the high pressure). The coffee is then sun dried for at least four hours otherwise the fermentation might continue and the flavours would change.
Climate change, explains Gray, has shifted the means of coffee production, as the industry relies on the ecosystem really being in balance.
While Gray says this style of coffee can help keep flavours consistent, Johnson notes that it also gives those involved in the process the opportunity to evolve flavours and styles by adding different yeast strains, similar to the winemaking process.
But word to the wise: Because this style is so labour-intensive, the coffee tends to be more expensive than other types, as you can pay upwards of $20 per pound for the brew and can only find it through craft-coffee vendors. While it may not be as expensive as some Kona-style coffees, it is definitely more than a $7 mass-market roast…..