Beer Body Through Mash Temperature Control

Many of us have tried a commercial or homebrewed beer that seems to be lacking in body.  Sometimes this is on purpose for the style or the “drink-ability”.  Other times with home brewers it is just a lack of understanding the beer you are brewing and how the mash temperature comes into play

Mash Temperature:  As many of us know the conversion of the grain starches into sugars happens during the mashing.  This is when you combine the hot water with crushed grain and let it sit for an hour or so as the grain’s enzymes convert starch to sugar.  Many home brewers stick to the standard 154 degrees Fahrenheit mash temp for conversion.  This is a great place to start and many styles will turn out great using this temp, but there is more to the range than 154.  Also on a side know I am only going to talk about beta conversion temps and not go into such things as protein rest.  So back to it…Let’s talk about two very different beers and the mash temp that suits them the best. 

First off a Blonde Ale, or as many of you call it a lawnmower beer.  This beer is best in the range of 154-156.  Since the ABV on this beer is relatively low you do not want to complete ferment out all of the sugars, and then end up with a thin dry beer.  By keeping the range at 154-156 you are allowing some of the long sugar chains to remain and by doing so the yeast will have a hard time converting them into alcohol thus leaving you some sugars for the body of the beer.

Now let’s look at the other end of the spectrum a nice big Imperial Stout.  We are talking about a beer that will end up with an ABV of 8%+.  So you know this is going to take a lot of grain to make and the first runnings of the wort are going to be extra sugary, but what temp should the mash be at.  For this style of beer you want a lot of the sugars to be converted into simple sugars that the yeast will not have a hard time processing into CO2 and booze.  A range of 147-150 should be the sweet spot for this.  Because of the large about of sugar in the wort the yeast will be working overtime just to get the simple sugars converted.  So even though there are more of them you will still expect some to remain to leave you with a nice body to the beer.   If you were to mash this out at 156 degrees you would end up with a beer that was overly sweet and thick as there would be too many complex sugar chains remaining that the yeast could not process.

So in summary think of mash temperature this way.  The lower the ABV on the beer the higher the mash temperature (with 156-158 being the highest you would want to go).  So the opposite end of the spectrum is the higher the ABV the lower the mash temperature (with 147 being the lowest you would want to go).