How does a commercial mash tun work?

Answered by Ricardo McCardle

A commercial mash tun is a key component in the beer brewing process, responsible for converting the starches in crushed grains into sugars that can be fermented. It is typically designed with a false bottom and a sparge arm, allowing for the sparging or lautering process to take place within the same vessel.

To understand how a commercial mash tun works, let’s break down the process step by step:

1. Grain Milling: Before the grains can be used in the mash tun, they need to be crushed or milled to expose the starches inside. This can be done using a roller mill or a hammer mill, ensuring that the grains are broken down into smaller particles without turning them into flour.

2. Mashing: The milled grains, commonly referred to as grist, are mixed with hot water in the mash tun. The temperature and water-to-grain ratio are carefully controlled to create an ideal environment for enzymatic activity. Enzymes naturally present in the grains, specifically amylase, break down the starches into simpler sugars such as glucose and maltose.

3. Conversion: During the mashing process, the enzymes in the grains work to convert the starches into sugars. The mash tun provides an insulated environment where the mixture of grains and hot water can be held at specific temperatures for a certain period of time, allowing the enzymes to do their work. This conversion process typically involves multiple steps, with different temperature rests to activate different enzymes responsible for specific sugar conversions.

4. Vorlauf: Once the conversion process is complete, the sweet liquid known as wort needs to be separated from the grain husks. This is done through a process called vorlauf, where the wort is recirculated over the grain bed multiple times until it runs clear. The false bottom in the mash tun helps prevent the grain particles from being transferred into the wort.

5. Sparging/Lautering: After the vorlauf, the sparging or lautering process begins. This involves rinsing the grain bed with hot water to extract as much of the remaining sugars as possible. The sparge arm, typically located above the false bottom, evenly distributes the hot water over the grain bed, ensuring efficient extraction. The liquid collected during sparging is combined with the wort from the vorlauf.

6. Wort Collection: Once the sparging process is complete, the wort is collected in the bottom of the mash tun. It is then transferred to the brew kettle for boiling and further processing. The spent grain, which has had most of its sugars extracted, is typically removed from the mash tun and can be used for various purposes such as animal feed or composting.

The commercial mash tun provides a controlled environment for the mashing process, allowing for the conversion of starches into sugars and the extraction of the sweet liquid called wort. The false bottom helps separate the wort from the spent grain, while the sparge arm assists in achieving efficient sparging and maximum sugar extraction. This crucial step in the brewing process sets the foundation for the fermentation and ultimately the flavor and quality of the beer produced.