What is a decoction mash?

A decoction mash is a specific multi-step mashing process that involves removing a portion of the mash, boiling it, and then returning it to the main mash. This technique is traditionally used to enhance the extraction of fermentable sugars and contribute to the flavor and body of the beer. The key aspect of a decoction mash is that it does not require additional water during the boiling phase; instead, the removed portion is boiled and then mixed back into the rest of the mash, thus raising the overall temperature and allowing for different enzymatic activities at higher temperatures.

In the context of brewing, the benefit of this method is that it can help in achieving higher efficiency in sugar extraction and can develop more complex flavors and aromas in the final beer. This stands in contrast to a single-step mashing method, which does not involve separate boiling of a portion of the mash, and other methods that might involve added water or focus on fermentation rather than mashing processes.