Mash Schmutzdecke

Some brewers have problems lautering their mash and a common practice is to slice the top of the mash bed with a knife or similar instrument to get better flow. This article will show you a better way to improve flow through your mash.

The German word: Schmutzdecke (pronounced: shmootz deka) , is a great word for what's happening. It means 'dirty layer' and that is what forms on the top of your mash bed as you recirculate or vorlauf the wort. That layer is a collection of all the fine matter from your wort that is filtered and collected on the upper grain surface. It clogs the pores of the mash bed surface and forms a dense layer. Because wort can’t flow as readily through that layer as the rest of the grain bed, that layer is the limiting factor in getting good flow through the mash bed.

Slicing the mash bed in several places doesn't provide much flow improvement. Those slices represent a tiny percentage of the overall surface area of the bed. A better method for breaking up the schmutzdecke is to break it up and mix it into the upper couple of inches of the mash bed. That way, the layers of schmutzdecke are broken into chunks and get mixed with the coarser mash grist. Wort flows easily around that jumble of chunks and grist. No knife needed. Just take a brewing spoon, paddle, or rake and lightly mix the upper few inches of the bed. No need to mix it thoroughly either, just a few strokes to break up that top layer and mix it into the upper part of the mash. Wort will flow much better through that mash bed.