Pot Still Distillation of Fermented Mash

The mash, now called “beer”, was added to a 9.5 L copper pot still. The copper pot still had a condenser filled with cool water that produced the ethanol condensation after being first evaporated by heating the “beer”. The copper pot still was placed on top of the induction burner for the distillation process to occur, and the temperature was set to 207 °C until the pot still thermometer reached 76 °C. At this point, the heat was reduced to 190 °C to avoid burning the “beer”, and the pot still reached 88 °C in 15–20 more minutes. The still thermometer should stay between 88 and 92 °C for optimal distillation to ensure the beer and grains do not burn. The distillation proceeded until the collection of 700 mL of distillate (“low wines”) was complete. The alcohol concentration by volume of the low wines was measured using an alcohol hydrometer, and the low wines were diluted by adding deionized (DI) water to the desired alcohol concentration (40% v/v) before starting the second distillation to keep uniformity and consistency from batch to batch. The pot still was cleaned first with a mild caustic solution to remove any stillage on the still wall, followed by a water rinse, then a mild citric acid solution, and another rinse, between batches to ensure no mix or contamination affected the process. For the second distillation, a 4 L stainless air still (Turbo Air Still by Still Spirits, Auckland, New Zealand) with an air fan-cooled condenser and electric heating was used. The diluted low wines (800–1000 mL) were added to the air still, and distillation commenced. The first 50 mL (“heads”) were collected in a glass jar; using a different glass jar, the following 300 mL were collected (“hearts”). The “tails” last portion of the distillate was discarded. The “hearts” distillate was stored in 750 mL glass bottles at room temperature. It may be diluted with DI water to reach a similar alcohol by volume from sample to sample before a sensory evaluation.