Building A Brewery, Chapter 4: For the Love of Microbes

Practical considerations

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Oakhold’s SysTech 3.5 BBL brewing system being moved into their brewery // Photo via Oakhold’s Facebook page

There are a number of practical considerations that also must define our recipes and the beers we produce, many of which are exacerbated when brewing irregularly on a small scale.

Homebrewers are notorious for developing recipes with all of the malts. A quarter pound of this, a half ounce of that—more malt varieties means more complexity, right? While that can be true in certain instances, a “kitchen sink” malt bill on the scale of a production brewery can be a logistical nightmare. It doesn’t make sense to buy a whole bag of specialty malt at wholesale prices if it takes a long while to use it, but it also doesn’t make sense to buy 10 pounds of that specialty malt from the homebrew store due to markups and economies of scale.

My experience at Fair State has put me firmly on the side of focusing on process to drive succinct and elegant beers that do not rely on excessive ingredient complexity. Many of the beers we will produce at Oakhold already adhered to that philosophy, but these practical considerations have forced us to make minor tweaks to recipes in order to simplify potential problems arising from inventory and storage and to help ensure that we are using the highest quality raw materials available to us.

Another difficult aspect of professional brewing that I have come to grips with is the need to streamline yeast handling in the brewery. When brewing five gallons or a half-barrel at a time it is trivial to purchase a new pitch for each brew day, and while the cost will add up it is not prohibitive. As a result, many of the beers I made as a homebrewer involved multiple commercial strains and oftentimes each pitch was used only once.

As a business, these expenses cut into the bottom line and using many different yeast strains becomes difficult when considering brewing schedule and the need to have viable yeast for each brew day. Fortunately, some of these problems are lessened with the non-Saccharomyces organisms used at Oakhold. Fairly low cell counts for organisms such as Brettanomyces result in the desired characteristics, and lactic acid bacteria such as Lactobacillus and Pediococcus are relatively easy to grow to high cell densities in a short period of time.

But simply growing up these organisms to mix with Saccharomyces isn’t enough; it is important to understand the organisms used and the role they play in the development of desired characteristics in the final product. Brewers would find it unacceptable if a strain billed as a flocculent lager yeast instead resulted in a phenolic beer with significant yeast in suspension. Yet all too often the organisms used in mixed-culture beers are viewed as a black box somehow resisting our efforts to understand their roles in the products we make. Because of these unknowns, mixed-culture beers are often viewed as “magical” or as a more pure expression of a brewer’s art.

As a result, some of the worst beer to ever pass my lips has been proudly presented to me as worthy of appreciation due to this propensity to elevate mixed culture beers into a category somehow removed from the established norms of industrial brewing. As a brewer, this concerns me. As a microbiologist, I am appalled. Such experiences will ultimately discourage beer drinkers from exploring the world of mixed-fermentation, and they are entirely avoidable.

Levi and I have spent a significant amount of time characterizing the strains and cultures we use. We know their approximate alcohol tolerance and IBU tolerance. We know which cultures are dominated by Brettanomyces, and which contain more aggressive lactic acid producers. We’ve learned that the our favorite Lactobacillus I isolated produces only lactic acid, that it can ferment trehalose (good for barrel-fermented and -aged sours), and that it is IBU tolerant but sensitive to late kettle additions and dry hopping. And while we recognize that there are many, many things we do not yet know about these organisms and their roles in our beers, we are determined to approach our fermentation practices with a focus on microbiology rather than relegating mixed-culture fermentation to the realm of “magic.”

Building terroir

Oakhold

Oakhold Farmhouse Brewery // Photo courtesy of Oakhold

Though my time at Fair State has reinforced the need to simplify yeast handling and malt inventory practices, there is one area where those lessons of streamlining will be happily disregarded. We take our claim of being a “farmhouse brewery” very seriously, and will incorporate that ethos into our beer over the years. We now have 25 acres on which to plant fruit trees and cultivate grain and hops. We have a deep well carrying water from over 300 feet underground into our brewhouse. We will have the ability to compost a significant amount of our spent grain to nourish the fruit trees we have planted. We will recycle water for irrigation of our hop bines and eventual grain crops.

In addition, we look forward to incorporating the local microbes found on our property into our mixed cultures and the resulting beers. One way to accomplish this is through the use of “spontaneous” inoculation via coolship. In the fall of 2013 our first two-barrel batch of truly “spontaneous” beer was brewed using a traditional lambic grist and aged hops, with inoculation via coolship occurring in the middle of a field on my uncle’s Christmas tree farm. After 18 months in a 59-gallon oak barrel, the beer resembled something similar to the lambic brewed in Belgium. And while that field in Anoka isn’t the same as our brewery in Northern Minnesota any more than it is the same as a brewery in Belgium, we are confident that we will be able to produce outstanding lambic-style beer at Oakhold.

I’m particularly enamored with the Baas-Becking Hypothesis, which states that “Everything is everywhere, but the environment selects,” a sentiment applicable to the fermentation of these types of beers. While the specific strains will differ, we already know that similar organisms exist in geographically distinct areas of the world where these types of beers are being made (e.g., The Zenne Valley in Belgium and Portland, Maine), and there is no reason to believe these similarities would not extend to Northern Minnesota as well.

We look forward to inviting these microbes into our brewery for the creation of beers that are brewed in the tradition of historical styles but are unique to our area and processes. Combined with the other local ingredients we are able to incorporate into our beers, we hope to capture the “terroir” of our rural setting and create beers that are distinctly “Oakhold.”

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