Where there’s sugar, there can be fermentation and distillation, and there are many sources of sugar in the world. Grains, fruits, sugarcane, and agave provide the stuff for many of the world’s most popular spirits, but vegetables—including tubers and roots—also have a long history of being distilled into alcohol.
That shouldn’t be a surprise. Fermentation is an ancient form of preserving produce, and—while we’re not saying that kimchi spirits are the next big thing—distillation often follows in fermentation’s footsteps.
Wherever cassava is a staple food, for example, people also tend to make beer with it. Also known as manioc or yuca, the starchy root is highly perishable once pulled from the ground, but there are many ways to process it—such as by making flour, which can then be used to make bread, pasta, or beer. It should be no surprise, then, that there are cassava spirits in places as disparate as Brazil, Cambodia, Cameroon, Rwanda, and Texas.
People sometimes refer to fermented drinks made from certain fruits, flowers, and vegetables as “country wines” because they’re typically a by-product of whatever’s grown locally. Not many country wines have a wide following, but rhubarb wine is an interesting exception. It starts with fresh rhubarb juice, often with sugar added and typically fermented with commercial yeast to reach up to 11 to 15 percent ABV—an acceptable base for distillation. You shouldn’t expect rhubarb “brandy” to taste like the vegetable—though you shouldn’t expect Scotch to taste like a handful of barley, either—but an infusion after distillation can add flavor as well as color.
Perhaps the most famous example of a spirit made from vegetables is vodka made from potatoes. However, there are many less orthodox yet more flavorful directions for distillers to consider.
The Search for Sugar
Yeast prefers sugar as an energy source when it creates alcohol as a by-product. Because yield is top-of-mind for any cost-conscious distiller, the relative lack of sugar in many vegetables can be a deal-breaker (unless you plan to fortify your country wine with sugar, as in the rhubarb example above).
To work with veggies, it’s worthwhile to consider those with the highest concentrations of sugar—or of carbohydrates that can be converted into sugar through the addition of enzymes. Vegetables with high sugar content include:
- sweet potato (13.9 g per cup)
- beet (13.5 g)
- pumpkin (8.1 g)
- winter squash (6.8 g)
- rutabaga (6.7 g)
- tomato (6 g)
- red bell pepper (5.9 g)
- carrot (3.4 g)
Compare those veggies with a few fruits commonly used in distillation, and their average sugar content: apple (19 g), pear (17 g), and peach (13 g).
If you’re prepared to add exogenous enzymes to convert starches into fermentable sugars, you can also consider vegetables with high starch content, such as cassava (averaging 38 g of carbs per 100 grams), plantains (32 g), yams (28 g), taro (27 g), and potatoes (17 g).
As I mentioned above, adding simpler sugars such as sucrose or honey can help ensure you get a high enough yield to make the run worthwhile. You can also co-ferment with a more fermentable base material, such as corn, apple, or molasses.
Carrots & Satsuma
Carrot is an unlikely base material for a spirit, yet the Reisetbauer distillery in Axberg, Austria, has garnered acclaim for its Karrotenbrand—an eau de vie with a sweet, earthy aroma of carrots, fruit, and savory vegetables.
Reisetbauer starts with 100 percent organic carrots sourced from Christian Schaddler, a biodynamic carrot grower not far from the distillery. Harvested in September and October, the carrots are chopped and liquified before fermenting eight to 10 days at 60 to 63°F (16 to17°C). Reisetbauer double-distills the fermented mash in its Christian Carl copper pot still, then rests it for three years in stainless steel. Reisetbauer bottles the spirit at 41.5 percent ABV.
Shochu made from sweet potatoes has become so traditional that you could be forgiven for thinking tubers are native to Japan. They’re not—Portuguese traders brought sweet potatoes over in the early 17th century—but they grow successfully there and have become a staple ingredient for the national spirit, which has a wide range of price and quality.
Japan now cultivates more than 500 varieties of sweet potato, known there as satsuma-imo. Distillers use more than 50 of those varieties to make shochu—especially in the south, where rice doesn’t grow as well. The most common variety used for shochu is kogane sengan, cultivated specifically for that purpose—it has a high yield per acre, high starch content, and flavors and aromas that shochu distillers value.
The koji mold used for the fermentation step may be cultivated on rice or barley—or on the sweet potato itself. Producers wash and trim the potatoes before steaming or roasting, retaining the skins, which provide a lot of flavor.
Courtesy Delta Dirt Distillery
From the Delta Dirt
Sweet potatoes are also popular in the United States, especially in the South, and they’ve found their way into a variety of spirits—such as the Sweet Blend Vodka from Delta Dirt Distillery in Helena, Arkansas. The Williams family grows their own produce for their Delta Dirt spirits, including the corn that also goes into the Sweet Blend base.
Head distiller Thomas Williams says it took a while to find the right proportions. “Honestly, the first batches during development were created using 100 percent sweet potatoes,” he says. “It had a wonderful aroma and [was] very flavorful on the palate. However, the taste profile was not exactly to our liking. So, we began blending with grains, including wheat, barley, and corn. We found that corn gave such a smooth balance to the sweet potatoes. From there, it was a matter of perfecting the sweet potato and corn ratio for the richest, most refined taste possible.”
Delta Dirt is an outgrowth of the Williams family’s fourth-generation farm and a way to add value to its crops. From the outset, it was a challenge to grow enough sweet potatoes to make the Sweet Blend Vodka. Now that it’s won double gold at the San Francisco Spirits Competition for three years running—earning it a rare platinum medal—the family says it will need to convert more of its other crops to sweet potatoes to meet the growing demand. Storage is another consideration: They harvest their sweet potatoes in the fall, then they need to store them at ideal temperatures and humidities to extend their shelf life through the production year.
When the Williams family started the distillery in late 2020, they were washing and dicing the sweet potatoes by hand to cook the mash. Since then, they’ve invested in a machine washer and cook their sweet potatoes whole. “The biggest challenge of all was developing a process that extracted the maximum amount of fermentable sugars from these sweet potatoes,” Williams says. That challenge “truly required us to experiment and innovate.”
Those experiments continue despite their run of success, as the Williams family works to meet demand for a homegrown product that’s found a place in the market alongside spirits made from more commonplace fruits, sugars, and grains.