After mashing and gelatinization, distillers add a thermostable multi-enzyme blend to the cooker. α-amylases in the blend hydrolyze amylose and amylopectin, yielding short-chain dextrins. Glucoamylases break these dextrins down further, yielding glucose. This glucose enables higher conversion (DE) in cook for higher fermentation throughput. The thermostable protease aids in liberating some of the starch that is bound to protein , as well as adding a bit of nutrient for the yeast. 

Making beverage alcohol involves converting starch into fermentable sugars. Yeast then transforms these sugars into alcohol. Liquefaction of starch is the first enzymatic step in this process. Liquefaction prepares starch for further breakdown to produce fermentable sugars. The liquefaction step is critical to the overall efficiency of a distiller's process. Effective liquefaction ensures complete starch conversion to fermentable sugars. 

A heat-stable blend of alpha-amylase, glucoamylase and protease delivers highly effective liquefaction.
In water below 50°C, unmodified starch granules are generally insoluble. To make them soluble, distillers use a process known as gelatinization. They heat the raw material - whether potatoes or grain - usually under pressure. That makes the starch granules absorb a large amount of water and swell to many times their original size. Then the pressure is suddenly released. That makes the starch granules explode. The granules lose their individual crystalline structure to become a viscous liquid gel.

Expanding and opening compact starch granules in this way prepares them for liquefaction. This step converts starch in the mash into a free-flowing liquid. The enzymes in a thermostable blend can go directly into the cooker. Non heat-stable enzymes must go into the mash tun after cooking. 

Starch is a mixture of two carbohydrate polymers; amylose and amylopectin. Both are made up of glucose monomers linked together by glucosidic bonds. The α-amylases in a multi-enzyme blend hydrolyze the 1,4-α-glucosidic linkages in amylose and amylopectin. That breaks the long-chain starch molecules into short-chain dextrins. The short-chain dextrins are more suitable for later saccharification to fermentable glucose.