What is the primary disadvantage of using a single-step infusion mash compared to a decoction mash for high-gravity beers destined for distillation?

The primary disadvantage of using a single-step infusion mash compared to a decoction mash for high-gravity beers destined for distillation is reduced starch conversion and extract efficiency. A single-step infusion mash involves holding the mash at a single temperature range optimized for enzyme activity. High-gravity beers, which are beers with a high concentration of fermentable sugars, require a significant amount of starch conversion to produce a wort rich in sugars. A decoction mash, on the other hand, involves removing a portion of the mash, boiling it, and then returning it to the main mash. This process, repeated several times, gelatinizes starches more effectively and promotes better enzyme activity. Gelatinization is the process where starch granules swell and burst open, making them more accessible to enzymes. The boiling also helps to break down cell walls and release more starches and sugars. For high-gravity beers, this is especially important because of the high concentration of starches present. A single-step infusion mash may not fully gelatinize all the starches or optimize enzyme activity sufficiently to achieve the desired high sugar content, resulting in lower alcohol yield after fermentation and distillation. In essence, decoction provides more energy and better conditions for maximum starch breakdown, a critical factor for high-gravity mashes where every bit of potential extract matters. If starch conversion is incomplete, the distiller will lose potential alcohol yield, and the final spirit may lack the desired flavor compounds extracted during a more thorough mashing process.