There are various ways to achieve a mash. The various methods different in steps and sometimes equipment. The three methods described here include
- Infusion Mashing
- Step Mashing
- Decoction Mashing
- Double Mashing
Infusion mashing is the most common for homebrewers due to its simplicity and is used widely on a commercial scale. A mash tun is the equipment for achieving the goal is to maintain a constant temperature over an extended time to allow for the starch modification in the ideal environment. The alpha and beta amylase perform differently at different temperatures and in this fluctuation will achieve different results. The fermentable sugars production is a curve over time Show a graph.
The range of equipment can go from a pot or kettle held at a constant temperature, to a home made mash tun built out of a cooler or keg, to professional mash tun, which is fairly sophisticated and expensive.
In essence the grains are combined with water that is above the temperature of the desired holding temperature. There grains are generally at room temperature, and the mash tun itself will effect the temperature due to heat loss. This is known as the efficiency of the equipment. The preheated water will lose temperature as its added to the grain and the tun, therefore calling for a higher initial temperature.
The temperature range and timing of holding the grains in the mash depends on the beer and style. Generally between 150 -160 degrees is where most beers will fall. And the timing can be from 1-2 hours.
Many recipes and styles will call for step mashing, which is achieved by stepping up the temperature over time to various levels. This method was originally created to deal with under modified starch for poor quality grains, however is proven at setting optimal conditions for the various enzymes which perform better at varying temperatures.
Heat can be applied to the wort to get to the next level of temperature. The number of steps vary, once again, based on the style and type of beer. These steps can range from 1 to 4 over just as many hours.
Decoction mashing is nearly the same as step mashing with the difference bing in the way it is done. It is achieved by removing a portion of the mash, heat it up to a higher temperature, and return to the mash, thus increasing the temperature. This is the technique used by most microbrewers. This technique along with step mashing helps to extract more of the sugars, provide a clearer beer due to the coagulation of protein, and adds color.
Double mashing calls for the addition of dry or liquid cereal adjuncts. In some cases this requires an additional cereal cooker which operates at different temperatures depending on the cereal. This is done to reduce the viscosity and to prepare the starch for the modifying enzymes. In other cases the cereals are added directly to the mash, and this is the most common for the home brewer.