Barley Starch for Brewers (II: Amylose)

Today is the first day of starch week on Beer and Wine Journal. (It’s like Shark Week on Animal Planet, but instead of ridiculous made-up crap about sharks, it’s facts about starch.) See the introduction to the series for an overview of the topics to be covered. Today’s post deals with amylose, one of the two main components of starch.


Glucose molecules joined in alpha 1 –> 4 linkages. In barley, amylose molecules typically range from 500 to 5,000 glucose residues.

The articles that compose this series on starch will have a few common themes. The most important is that the word starch refers to a variety of things, not a single, defined entity. For example, starch is composed of amylose and amylopectin. Any combination of these two molecules — from 1% amylose to 99% amylose — would be considered a starch, even though differing mixtures would have different properties.

Additionally, in real life situations, starches maybe complexed with proteins and other molecules. These other molecules can change the properties of the starch. Starch is also packed into different sized granules, which affects its solubility. Even heating and cooling starch can change its structure and its properties.

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