Ask the Experts: What is a Triple-decoction Mash?

Homebrew expert Brad Smith, author of the Beersmith homebrewing software and the voice behind the Beersmith podcast, answers an important question about triple-decoction mash.

Brad Smith Mar 6, 2019 - 3 min read

Ask the Experts: What is a Triple-decoction Mash? Primary Image

A Craft Beer & Brewing Magazine reader recently asked us the following question:

What is a triple-decoction mash, and why would I need to do one?

Triple-decoction mashing is a traditional brewing technique used extensively in Europe for brewing beer. A decoction mash includes at least one step where a portion of the mash, including the grains, is removed and heated in a separate vessel to boiling temperature and then mixed back in with the main mash to raise the temperature of the mash. By “decocting” a portion of the mash and heating it to a boil, you can raise the temperature of the mash for each step, much as you would when adding water for a traditional infusion mash.

As with other mash techniques, the mash may be completed in one or more stages or steps where the grain is rested at different temperatures. Decoction mashing was developed in the period before thermometers were in wide use. Drawing the correct percentage of the mash and bringing it to a boil at each step produced a consistent temperature for each step.

A triple-decoction mash has, as the name implies, three steps, and the extra steps were used in part to aid in the conversion of under-modified malts before malting science had developed to the level we see today. Modern malts are all highly modified, so only a single conversion step is needed to convert the sugars in the malt. It is rare that brewers perform three- or even two-step mashes anymore.

One reason brewers rarely practice decoction mashing these days is the added complexity and time. It requires a separate vessel and heat source and can be somewhat messy to perform. In addition, the full triple-decoction adds several hours to your brew day. However, a unique German malty flavor and character that comes from decocting and boiling the mash can be difficult to completely replicate using an infusion mash. Some brewers have tried adding small amounts of melanoidin malt, which will partially replicate the flavor, but to capture all of the character, you do need to do a decoction. However, I personally would not do a triple-decoction but would instead do a single-decoction if you want the authentic decocted-beer character.

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