Whiskey aficionados know which grains they like in their spirit. They can distinguish between the sweet softness of corn, the mellow creaminess of wheat, and the sharp grassiness of rye.
But do they know which kind of corn or rye they like best? Probably not. But this might be the direction that craft whiskey is headed.
Drinkers already understand varietal flavors. In the wine world, there’s one species of grape, Vitis vinifera, and its many varieties, from jammy merlot to steely chardonnay, are renowned for their distinctions. Michael Swanson, distiller at Far North Spirits in Hallock, Minnesota, wondered, does the same hold true for whiskeys made from different varieties of the same grain?
“Our hypothesis was that there would be a difference between the varieties [of rye] in flavor, based on how differently they act in the field,” he explains. “We were prepared for the null hypothesis to be true, that there would be no difference in flavor, and that would be a result in and of itself. What we found is that’s not true at all. There are a lot of differences.”
Most whiskeys from big distilling companies can’t advertise the variety of grain, because at that volume, they don’t have a choice. The big players simply buy up silos full of commodity grain, which likely contains different varieties, and distill and barrel it all together. After years of aging and lots of blending from thousands of barrels, they can create a consistent house style so your Maker’s Mark tastes the same year after year.
But if there’s one advantage small whiskey producers have over big companies (and to be clear, there are not many) it is the luxury to be choosy about your raw materials. Swanson, who grows all the grain for his Roknar Rye Whiskey, established 15 one-acre test plots, each with a different strain of rye. Some grew tall, while some flopped over in the fierce prairie wind. Some varieties yielded over 100 bushels per acre, while others barely hit 40.
He then milled, mashed, fermented, and distilled all the ryes under identical conditions, and presented these white distillates to a series of blind tasting panels. These young spirits tasted remarkably different (The Growler participated in one such panel two years ago) and the results will be published in Swanson’s report to the MN Department of Agriculture.
But the critical step, one that adds a lot of new variables, and one that makes whiskey a beautiful spirit, is barrel-aging. Conventional wisdom holds that a barrel mellows out a spirit—smoothing down the rough edges, covering up shoddy distillation or bad grains, and plastering over the flavor of the spirit with that of charred oak.
Swanson put his single-variety rye spirits each in the same kind of barrel, made by the same manufacturer in the same place on the same shift, and let them rest next to each other for 18 months. He expected the barrels to take over the flavor.
“My hypothesis for this part was completely the opposite—that the barrels would smooth over any of the differences that the varieties might have had,” he says. “What we’re finding here is that some of the differences between the varieties have been amplified by the aging process.”
Far North is releasing some of these various single-variety ryes in their Seed Vault Series. But more importantly, they are making their research on the flavor potential of these rye strains public, so that other distillers can access their work and build upon it.
The question is: Will Minnesota’s craft distilleries pursue varietal-specific whiskey?
To some extent, it’s already happening. RockFilter Distilling in Spring Grove is growing many different heirloom corn varieties for their various bourbons. Several distilleries partner with farmers to grow a specific grain, or to grow organically. Now, this information is making it onto labels—becoming an integral part of the whiskey’s identity. And for a product that often struggles with transparency and provenance, that is a great development.