Malting and mashing complement each other.  What wasn’t achieved during the malting is to be fabricated during the mashing.  How proteins are handled is of great importance when making a great brew.

Soluble proteins have a very positive influence on the foam and give the beer body and mouthfeel.  As these proteins are dissolved by proteolytic enzymes, amino acids are created.  These amino acids are important nourishments to the yeast and the aim of the protease rest should be to solely satisfy this requirement.  Any reduction beyond this point will only lead to unnecessary loss of body and mouthfeel.  Bavarian beers have a good body and plenty of mouthfeel, so it’s important to get this right.

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Hubert Hanghofer wrote how the malt quality should influence the mash schedule.  He produced the following table with recommendations for the protein rests needed according to the Kolbach Index in the malt’s specification.  Note that EBC spec-sheets may give the same value as SNR (Soluble Nitrogen Ratio).

Kolbach Temperature Minutes
< 35% 50C 30
35-38% 54C 20
38-41% 57C 10

A modification higher than 41% won’t require a protein rest at all. Which explains why certain recipes using the Hochkurz schedule start immediately at 62C whereas others at 50-55C.

Whatever the recipe, it seems to me that it is wise to adapt one’s mash schedule according to the malt available and schedule a protease rest whenever necessary.

Anything to keep the yeast happy!