Heirloom corn has taken the craft whisky scene by storm. It’s often too costly for large-scale producers to use anything but Yellow Dent corn, but smaller craft producers are seeing it as a way to differentiate their products from the standard. Heirloom corn is open-pollinated, which means not only that each kernel on a cob will produce a plant, but also that the offspring of those seeds will be identical to the parent plant. Heirloom varietals of corn as we know them have typically been saved through generations, yielding a plant that has remained virtually unchanged for generations. But there are also ‘beyond heirloom’ varietals made by crossing two heirloom varietals to create an open-pollinated hybrid, often producing greater diversity in flavours and colours.
“Heirloom corn mostly fell out of favour due to the introduction of chemical controls for fertiliser and the introduction of F1 hybrids which took two or more open pollinated inbred lines and bred them together to increase production when coupled with chemical controls,” says Alan Bishop, head distiller of Spirits of French Lick. “This was during the so called green revolution. While these new varieties yielded better and grew far more uniformly, meaning they could be planted in closer spacing than in past varieties, they also led to lower protein and starch content in the corn and a massive loss in both diversity and flavour in corn. The back to the land movement of the 70s initially brought old open pollinated corns back to the small holder and gardeners who realised their inherent nutrition and perhaps as importantly or more so their intense flavours.”
Lisa Wicker, president and head distiller of Widow Jane in New York, likens heirloom corn to heirloom tomatoes, noting that you can have a beautiful and perfect-looking tomato in a grocery store that doesn’t taste like much, while often strange looking and sometimes ugly tomatoes that come in all shapes, sizes and colours can be the most flavourful.
In Texas, distilleries like Balcones and Ironroot Republic are also differentiating themselves through the use of heirloom corn.
“We are definitely continuing down the path of experimentation with new varietals,” says Jonathan Likarish, owner and head distiller at Ironroot Republic Distilling. “In fact this week we are doing some experiments with a corn called ‘Glass Gem’ Flint and I have a few more that we will be using in the next few months. As our stocks are getting older, we are beginning to be able to answer an important question that we had early on: As with grain flavours or peat flavours in Scotch, will the influence of the heirlooms diminish as the whiskeys mature and take on more barrel character, and if so, will it eventually negate the influence of heirlooms all together? In short, as expected some of the grain characters give way to barrel notes, but interestingly enough, all of our heirlooms are still uniquely distinguishable from one another and maintain their complex nature.”
“The colour variations in corn come from the expression of different amino acids in the pericarp or aleurone layer of the kernel,” Bishop says. “Each colour is associated with particular amino acids such as zeacyanin (yellow, orange), anthocyanin (red, blue, purple), and carotenoids (orange). These colours all carry unique flavours. Blue/red can contain black cherry, spicy pepper notes, and sometimes blackberry/blueberry notes. Carotenoids are responsible for Safflower aromas and tastes and also give very creamy notes. These amino acids are either water soluble or fat soluble so they carry over very easily during distillation, particularly in a pot still, in either the water that is distilled or along with the long chain fatty acids that we are breaking down into esters. The fatty acid soluble types will be more or less apparent depending upon how long they are in contact with heat and catalysed by chemical reactions in the still.”
Bishop points out the heirloom corn revolution in the distilling industry is still in its infancy, and it’s now moving toward distilling grains such as wheat, rye and barley as well.