Chapter 9

Mashing

Infusion Mashing

Infusion mashing, although not as popular, is a classical British method of brewing ales and stouts, where the brewer produces and recovers the extract at a single mash temperature, called the conversion temperature. Unlike other mashing methods, it doesn't require a series of different temperatures and rests. The conversion temperature represents a compromise between the optimal temperatures for alpha- and beta-amylase. Any deviations from the intended temperature could affect the beer since there is only one temperature determining makeup.

Mash In

The process itself begins by preheating the mash tun with steam or hot water to minimize heat loss.

Strike Temperature

The strike temperature is the temperature of mash water to be infused with grist to hit the desired mash temperature during mash-in.

Stand Time

The mash is allowed to stand, without mixing, or addition of heat, for a given time to allow starch conversion to take place. The conversion temperature is usually in the range of 60 to 65C for British malt and 63 to 70C for American two-row malt (31). The higher mash-in temperatures for American malts is due to higher levels of alpha- and beta-amylase in the malt.

Mash Off

Following mashing, the temperature of the mash is raised between 75 and 78C, the "mash-off" temperature. At this temperature, enzyme activity is deactivated and bacterial action is precluded.

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