Understanding Malt Enzymes and Color in Beer Brewing

This week I take a look at malt enzymes vs malt color and how enzymes affect conversion of the malt during the beer brewing process.

Malt Enzymes and Mashing

In all grain brewing, enzymes are very important during the mash as they are needed to convert the longer starch chains in the malt into shorter sugar chains, primarily maltose, that is easily consumed by yeast. The two main enzymes are alpha amylase and beta amylase, and each are active in a slightly different temperature range.

The overall level of enzymes is measured and published by the malt supplier as a single number called diastatic power. The term “diastatic” refers to “diastase” enzymes, of which the two major ones are the alpha and beta amylase mentioned above. The range of diastatic power varies from zero to approximately 300, with an average Pale malt in the roughly 150-200 range.

Malt Enzymes vs Malt Color

Malt enzymes are developed during the malting process. However, malt enzymes are broken down as malts are kilned at higher temperatures, so not surprisingly most of the diastatic enzymes in your beer come from the base malts such as pale malt, pilsner malt, vienna and munich malts. Also non-barley malts don’t add much in terms of enzymes in most cases, except for malted wheat and rye.

The chart above from Briess Malting shows the enzymes in diastatic power vs malt color for lighter colored malts in the Briess product line. As you can see the highly enzymatic malts are their Pale 2-Row Brewers malt, vienna, Pale Ale, Rad and White Wheat and Rye. Mild malt, and Munich have substantially lower levels of diastatic power. The darker kilned malts, crystal/caramel malts and roast malts provide almost zero enzymes to the mash.

The reality of modern malts is that most beers made with an all malt base (barley or wheat) have little to worry about as all modern base malts are highly modified. Highly modified means that the malts have a very high level of enzymes.

Concerns over low enzyme levels generally kick in when working with a grain bill that has a high percentage of non-barley grains, unmalted ingredients or dark specialty malts, or you are doing a partial mash. Partial mash is a particular concern as you need to make sure you add enough base malt to provide the enzymes needed to convert your reduced size mash.

There is a custom field added in BeerSmith 3.1 (and higher) that displays the diastatic power for an entire batch. It does this by averaging the diastatic powers from the grains over the batch. You can display this by going to My Recipes view and then using View->Customize Columns or open a recipe and click on the “Select fields” to select the custom field from the recipe design tab. A value above 30 is for this field is generally considered good enough to self-convert.

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