high mash temp.

So I overshot my mash temp by 6 degrees and myash was in the upper 150s. What can I expect this to do to the taste and mouthfeel of my beer. I'm brewing stout today.

In general, a mash temp in the upper 150s will lead to longer chain sugars resulting in a less fermentable wort. This will likely increase the beer's mouthfeel (perhaps slightly more than desired) and probably raise the FG of the beer.

Were you using a strike water calculator? If not, I'd recommend using one going forward. Personally, I use the one in the beersmith software and I've had pretty good results. Also, if you overshoot the temperature in the futuer, I'd recommend stirring the mash very well and/or adding a few ice cubes until you reach your desired temperature.

Overall, the wort will be less fermentable leading to what could be a FG that is quite high. This will also mean the beer will be quite sweet.

Good luck! Cheers!

As said, it will result in less fermentable wort and higher FG, but assuming you're not brewing dry stout this is not big issue.

I think if it ends up too sweet, I'll brew a couple quarts of strong coffee and make a coffee stout.

You could always cool it down and still hit your target. Simply stirring will cool things. It also gives you time to make sure you have broken up all the dough balls. If stirring doesn't get your temp down add some cool water or ice cubes and stir that in. no big deal

The long-chain sugars produced by high mash temps are nowhere near as sweet as table sugar. Like, less than 20% as sweet. They will make your beer thicker, which is swell in a stout. As long as your mash temps are under 160, you'll make beer. High temps are more of an issue for styles you want thin & dry, like IPA and Saison.

For a stout you'll be just fine. Next time mash at low 150's if you want a drier beer, but you'll be OK on this one.

Also, you can just extend your mash an extra 30 minutes to an hour and it will dry out as well.

daksin said:

Also, you can just extend your mash an extra 30 minutes to an hour and it will dry out as well.

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I started out with mine at around 158F. My mash temp was supposed to be 152F. I stirred about 10 minutes until it dropped to 153, then started my 60 minute mash. Is stirring that long normal?


I'm brewing a Fat Tire clone, via BIAB, if that helps.

Yesfan said:

I started out with mine at around 158F. My mash temp was supposed to be 152F. I stirred about 10 minutes until it dropped to 153, then started my 60 minute mash. Is stirring that long normal?

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You really only need to stir long enough to make sure all the grain is wet and that there are no doughballs you need to smash down. Just keep some ice cubes and boiling water on hand if you need to make any temp adjustments. Your beer will be fine, by the way.

Yesfan said:

I started out with mine at around 158F. My mash temp was supposed to be 152F. I stirred about 10 minutes until it dropped to 153, then started my 60 minute mash. Is stirring that long normal?


I'm brewing a Fat Tire clone, via BIAB, if that helps.

Click to expand...

Well, you can't really "start my 60 minute mash" after it's been mashing for 10 minutes. It doesn't really matter, but since conversion is mostly finished in 15-20 minutes, you had lots of conversion before you got to 153. There is no advantage to mashing longer, really, once conversion has occurred.

Yesfan said:

I started out with mine at around 158F. My mash temp was supposed to be 152F. I stirred about 10 minutes until it dropped to 153, then started my 60 minute mash. Is stirring that long normal?


I'm brewing a Fat Tire clone, via BIAB, if that helps.

Click to expand...

It's pretty normal in my brewery. But maybe you could go a few degrees cooler with the strike water next time.

Yooper said:

Well, you can't really "start my 60 minute mash" after it's been mashing for 10 minutes. It doesn't really matter, but since conversion is mostly finished in 15-20 minutes, you had lots of conversion before you got to 153. There is no advantage to mashing longer, really, once conversion has occurred.

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I would disagree a bit here- the starch conversion is done very quickly, but there's a lot that can happen after your starch is converted. By extending the mash you're allowing extra time for the enzymes to work on the sugar you've created- the only thing those enzymes can do is continue to chop up the longer chain sugars/dextrines. That's part of why we mash out when fly sparging (and why some pro brewers mash for only 15-20 minutes)- to preserve the mash profile. Longer mashes = thinner beers, in general.

Sure, some of your beta amylase is going to be denatured or working poorly, but even the alpha amylase is going to continue to work happily chopping up whatever it can get its hands on. I would think that if you mashed too high for 15 minutes, you could let the mash go on a lot longer to help cut down on the mouthfeel you might otherwise get. I'm not sure if cooling it down would help or not, though, considering some beta amylase may be partially or totally denatured. That sounds like a complicated biophysics problem I don't feel like doing.