Tech Notes: Our Ground Control Batch Brewer

Posted by Ryan O'Rourke on February 7, 2019 in Uncategorized

We do a lot of things differently at Ironclad Coffee Roasters. Part of the joy we experience, every day at our flagship café, is simply witnessing what some of our staff have taken to calling the “Willy Wonka effect”: the look of sheer child-like wonderment that appears on our customers’ faces when they see something in our shop that they’ve never encountered anywhere else in the coffee-drinking world.

One of the sure-fire sources of our patrons’ astonishment is our Ground Control batch brewer’s multi-part brew cycle. A product of Voga Coffee, a coffee technology company based in Marin County, CA, the Ground Control turned heads at SCA Expo in 2018, winning Best New Coffee Product for its single-group Cyclops brewer, and has received glowing accolades in specialty coffee trade publications such as Sprudge, Daily Coffee News and Barista Magazine.

The dual-group model our shop uses, the Ground Control II, allows us to brew two batches at once –
sometimes a necessity on a busy morning!

Aesthetically speaking, it’s easy to see what the fuss is about: about halfway through each step in the three-part brew cycle, a vacuum pump siphons the infused brew up from the grounds bed, which sits in an immersion-method brew basket at the base of the machine, into one of the glass bulbs that sits above each group. With an instantly recognizable whirring and buzzing, the machine aerates and mixes the brewed coffee before your very eyes; layers of lighter and heavier volatile aromatic compounds in the liquid naturally stratify, and a heady foam forms on top. Then all that liquid dispenses into the airpot – and repeats, now that it’s got your attention, for two more rounds.

Visual spectacle aside, there are a number of quality-impacting factors that led us to take the Ground Control’s patented brew method over that of a traditional batch brewer. Voga Coffee co-founders Dr. Josh Avins, Eli Salomon and Jason Sarley designed the prototype in the kitchen of Salomon’s San Francisco apartment, drawing on Avins’ background in chemistry to pioneer a multi-step brewing cycle for coffee – standard practice in a laboratory setting, where extraction theory favors multiple smaller extractions over a single large one. Each phase of the extraction sequence has different characteristics, and targets a different set of the coffee’s qualities to bring out. The first “pass,” extracting the lightest molecular compounds from the coffee grounds, isolates the coffee’s natural sweetness and acidity; the second pass extracts the heavier compounds responsible for complexity and aromatics. Then a third, final pass absorbs the heaviest volatiles that produce the body, viscosity and mouthfeel of the coffee.

The SCA Flavor Wheel organizes a broad spectrum of naturally occurring flavors in specialty coffees. It is incumbent upon the brewer to choose a method that brings out the coffee qualities he or she desires in the cup. Source: CoffeeAttendant.com

Each of these separate brewing passes dispenses into the airpot in turn, creating a layered quality to the resulting batch brew that isn’t found among regular top-down, spray-head drip brewers; preserving more of the lighter, brighter, fruity and floral flavors that make each of our carefully-sourced single origins and blends so distinctive; finally, producing greater consistency across batches of the same coffee over time. Furthermore, with an Android-based user interface, giving us access to brew temperature, duration and volume, our staff can program and tweak unique brewing “recipes” for each coffee, adjusting the parameters until we get exactly the flavor profile we’re looking for.

The best part is, the Ground Control brews at drinking temperature, meaning – unlike with drip coffee at some places – you don’t have to wait twenty minutes for it to cool! If you take your coffee with cream, we recommend not using too much – or better yet, ask our staff to steam some for you! Honestly, it tastes good enough black that we prefer it that way. The choice is yours, of course.

We like cream in coffee too sometimes – but with ours, a little goes a long way.

Stay tuned for next week, as we roll out the third of a total of seven single origins at our café and online store! Till then, enjoy this fine milder weather – we’ve been keeping the garage door at our shop open, while it lasts!

For the Ironclad crew,
Ryan


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