Amylases (what is sugar #07)

Sugar, saccharides, are essential to fermentation. Some sugars like corn syrup defy this rule but on average adding some sort of carbohydrate to your brew will result in some sort of fermentation.

Despite this general rule some sugars simply can not be fermented even if they are made from fermentable sub units like glucose. This is where the effect of an isomer applies.

A simple sugar like glucose is readily fermented by yeast. As part of a larger unit like maltose, 2 glucose units, this is still fermented by yeast. Longer chains are where yeast struggles. This is where starch and cellulose sit.

Starch is made of glucose; cellulose is also made from glucose but only one can be fermented. The reason for this is because each is an isomer and this changes the way each molecule is laid out. In this case cellulose is inaccessible for fermenting species like yeast. Starch however can be fermented.

This is where amylases come in. Amylases are an enzyme group that breaks down starch chains. In this case the 2 parts are called amylose and amylopectin. Amylose is a linear chain of glucose. Amylopectin is like a spiderweb of glucose chains that occasionally branch into new chains.

Each amylase enzyme works on one or the other of these 2 starch chains. This directly effects how much you can ferment when brewing beer. A brew highly dependent on the complex ingredients you add like starch rich barley, wheat and similar.