Effect of Mash Temp

Can someone direct me to some good reading about how low vs. high mash temps affect the final product? I'm also curious to learn more about how the various temps affect different malts. I hear people make references to these two phenomena often, but I don't understand them yet. I've read "how to brew" cover to cover, and I haven't come away with much on these two questions.

From my understanding, within the acceptable range, the higher the temp the less fermentable sugars you get.

Lower mash temps produce more fermentable sugars, which will result in a lower FG, resulting in significantly less body/mouthfeel in a brew.
Higher mash temps do the exact opposite.

The typical mash temp range is from 148-158F. So if you mash in the lower end of the range, 148-151, you'll get lighter body brews. Mash in the middle of the range, 152-154, you'll have a more medium body brew. Mash at above 154 and you'll end up getting a more full body brew. I wouldn't mash above 158F, although some have gone up to 160F. I also wouldn't mash below 148F.

Do an experiment for yourself. Mash in the three ranges, with the exact same recipe, using the exact same yeast, and ferment at the exact same temperatures. With all else being equal, you'll end up with three different FG's and body levels as a result.

BTW, the current version of BeerSmith takes mash temperature into account when it figures out the FG. It also takes the yeast strain into account so that you have a much better idea of what to expect.

Golddiggie said:

Lower mash temps produce more fermentable sugars, which will result in a lower FG, resulting in significantly less body/mouthfeel in a brew.
Higher mash temps do the exact opposite.

The typical mash temp range is from 148-158F. So if you mash in the lower end of the range, 148-151, you'll get lighter body brews. Mash in the middle of the range, 152-154, you'll have a more medium body brew. Mash at above 154 and you'll end up getting a more full body brew. I wouldn't mash above 158F, although some have gone up to 160F. I also wouldn't mash below 148F.

Do an experiment for yourself. Mash in the three ranges, with the exact same recipe, using the exact same yeast, and ferment at the exact same temperatures. With all else being equal, you'll end up with three different FG's and body levels as a result.

BTW, the current version of BeerSmith takes mash temperature into account when it figures out the FG. It also takes the yeast strain into account so that you have a much better idea of what to expect.

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That's a wonderfully useful explanation. Thank you!