Triple decoction mash schedules with a large percentage of lager malt can include an acid rest, but the acidulation of the mash can easily take upwards of two hours. Other more precise, controllable and efficient methods of mash pH control are available to the modern day masher, and only fanatical triple decoction traditionalists need attempt such a rest. Protein Rest is a confusing term as it can have several different meanings. These enzymes degrade globulins and albumins to peptones and polypeptides. Let's back up a little and take a closer look at proteins.
All proteins are nothing more than groups of amino acids.
Amino acids are essential compounds for growth which are composed of nitrogen, hydrogen, oxygen and carbon. That's enough chemistry. Proteins fit into the brewing process in three essential ways. One, when decomposed to amino acids they provide yeast with essential nutrients for growth and metabolism. Two, they significantly affect the body, mouthfeel and head forming and retaining properties of beer.