The Agrarian warm room is a deceptively simple place. It is kept at a precise 74 degrees Fahrenheit year-round, without exception. Circumventing the entire room is a 12 inch wide ribbon of radiant heat banding that does just that - it radiates a warm, consistent heat evenly and without fail. This well insulated space houses billions upon billions of single celled wonders that we carefully keep comfortable. All of these beautiful tiny friends reside in “rooms” within this warm room, made of either glass, stainless or wood. Each of these vessels are host to a vast array of microbes, all at different stages of a great party!...
An Elegant Party
Some vessels have just arrived, likely having pre-partied elsewhere, awkwardly discovering all the other guests within and checking out what there is to eat. Some vessels are deeper into the party, everyone is best friends within and they’re all on the dance floor having an amazing time. Some vessels have been raging for a while now, and things are starting to get a little weird in there… And for certain vessels, having partied in the warm room long enough, the party is over - it's time to mellow out, settle down and leave.
A Classic Approach
Many classic Belgian breweries have warm rooms set at unique temperatures designed around their particular preferences for re-fermenting in the bottle. Orval prefers to keep their warm room at a cool 59 degrees Fahrenheit - favoring the regular ale yeast in their mixed strain bottle conditioning culture.
Warmth & Diversity
At Agrarian, we like what the party provides when it’s kept at 74 degrees Fahrenheit. Since we are not simply conditioning bottles in our warm room, but also encouraging active and evolving biological activity in wild vessels and barrels, this temperature successfully accommodates it all. At any single point in time our warm room may be inhabited with: mixed cultures, spontaneous fermentations, Belgian and French ale yeasts, lactobacillus focused blends, auto-fermented farm fruit fauna, etc. We are always delighted with the results our warm room produces.
The Path Forward
Tasting, blending, further inoculation and topping-up occurs at regular intervals for upkeep and to map where on the path certain creations reside. For some of these projects, incredible transformations take place within a few months, whereas others may take a few years. Each barrel has its own personality, learning how they all behave is part of the journey.
Oak & Angels
Oak is porous and naturally breaths over time. Flavors concentrate and barrel fluid levels drop gradually. The "Angels' share" (a term for the portion of volume lost to evaporation during barrel aging) is topped-up regularly to prevent the prevalence of oxygen. The "Devil's cut" (a term for the portion of volume that is absorbed into the wood) tends to be minimal since we always keep our barrels full and fully hydrated.
Acetobacter is a ubiquitous bacteria in the world, and keeping the oxygen levels at a minimum in barrels keeps the development of acetic acid (vinegar) at bay. Oddly enough, we do take exception to this practice when we are looking for a slight bit of acetic acid zing to compliment certain old-world styles...
Pressure & Character
In addition to barrels and bottles, we have several other special vessels that often live in our warm room as well. One of these is a full-batch sized tank that has a beautiful mixed culture of regular and wild yeast. We have the ability to keep this vessel under pressure during warm conditioning/fermentation at upwards of 30 psi (equivalent to being 70 feet under water!). This allows us to delve into the fascinating biological expressions of fermentation under pressure! Yeast and bacteria behave quite differently under significant pressure, and their resulting flavor and aroma contributions can be pleasantly unique. The current mixed culture we have in this tank yields lovely tropical notes of pineapple and guava when kept warm and under pressure.
Join The Grand Farmhand Society
Nearly all of the special projects going through our warm room program are destined to go into bottles for our Root Cellar line and/or directly to our Grand Farmhand Society beer club. If you are interested in exploring this journey with us, join our beer club for advanced and/or exclusive access to all of our finest creations. We have launched our club in Kickstarter for 2018. AGRARIAN KICKSTARTER