This is added back into the mash in order to raise the mash to the next step, saccharification at 148F. While resting once any remaining mash from the first decoction reaches 122F it can be added back into the mash.Īfter the protein rest, a thick decoction is again pulled and again it is brought to saccharification temp and held for 30 minutes before boiling for15 minutes. In this case, a protein rest of 122F is held for 60 minutes. Stirring and checking the temperature to make sure the next step is not overshot. The it is slowly added back into the the mash. The decoction is then brought to a boil and allowed to boil for 15 minutes. This allows and enzymes in the decoction to do their job and convert as many of the starches as possible. I heat the decoction to saccharification temperature and let it rest for 30 minutes. I pull 1 quart of thick mash for every pound of grain (or as close to it as possible). Now the method I use may be different than most accepted methods but that’s OK. After 45 minutes I would pull a decoction. During this time the PH of the mash has a chance to stabilize and the enzymes are released into the mash liquid. My normal procedure for a triple decoction mash would be to dough in at the acid rest temperature of 95F and let it rest for 45 minutes. A decoction can use a large portion of the mash, up to 1/3 is not uncommon. If the enzymes are boiled, they will be denatured and thus no longer able to convert start to fermentable sugar.
The reason for this is the enzymes needed to convert the starches will primarily be in the thin portion of the mash. The portion boiled to move from the acid rest to protein rest and to saccharification rest is done with a thick portion of the grist.
There are some that feel that a decoction mash also contributes to the head retention common on a lot of German beers.Ī decoction mash is accomplished by extracting a portion of the grist and boiling it.
These flavors are created during the maillard reactions that happen when the grain is exposed to the high temperatures during the boil. Or is it? There are a number of German breweries in Southern Germany that still do decoction mashing as they feel that there are flavor compounds developed during the decoction that cannot truly be repeated any other way. With the fully modified over over modified malts we have today, a decoction mash really isn’t needed. Repeatable quality is the goal of every brewer. Now the Germans probably didn’t understand each of the rests like we do today, but they knew it produced a superior beer and allowed them to repeat the quality.
The repeated boiling of the grains during the decoction allowed full access to the starches and accomplished the needed increase of the temperature to move from acid rest, to protein rest to saccharification rest to mash out. With under modified malts the cell walls were not broken down well enough to allow the enzymes responsible for converting the starches to fermentable sugars to convert everything. This was developed by the Germans during a time when malt quality was not consistent and temperatures could not be measured.
What is it? Why was it done? Is it still done? How is it done?ĭecoction mashing is an age old technique for stepping the mash through the various temperature ranges without direct heating.