High temp during partial mash

I'm doing my first partial mash which calls for a beta rest at 140 F for 30 min and an alpha rest at 158 F for 30 min. The beta rest went fine, but when I turned on the heat a bit to do the alpha rest, is seemed to heat up a little slow. I let it sit for a while and checked it again, temperature was around 145, I moved the thermometer a bit, and it suddenly skyrocketed up to about 170 before I could cool it with some more water. Will this damage my grain in any way, or should I just RDWHAHB?

"Relax, have a homebrew"

You should be fine. You might wind up with a dab more tannins, but probably won't notice the difference.

I hope you cooled it down as quick as you can. Not too much damage will be done especially if its a partial mash. And yes RDWHAHB, not much you can do now.

barroomhero1234 said:

I hope you cooled it down as quick as you can. Not too much damage will be done especially if its a partial mash. And yes RDWHAHB, not much you can do now.

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I cooled it within a couple of minutes, now I'll just see how it turns out.

Thanks for your reassurance, both of you.

It can be really tricky to change the temperature of your mash on a stove top. Relax, you probably moved your thermometer from a cool spot to a hot spot. If your whole mash was that high you may have denatured some of the enzymes, but you should be OK if you cooled quickly. Next time use an online calculator and you will be able to figure out how much boiling water to add to your mash to reach the desired temperature, much more accurate and less stressful.

beerkrump said:

It can be really tricky to change the temperature of your mash on a stove top. Relax, you probably moved your thermometer from a cool spot to a hot spot. If your whole mash was that high you may have denatured some of the enzymes, but you should be OK if you cooled quickly. Next time use an online calculator and you will be able to figure out how much boiling water to add to your mash to reach the desired temperature, much more accurate and less stressful.

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Aye, that seems like a much better method. Will do for the next brew!

I tried a stovetop partial mash once and had similar results as you mentioned. My temps got to 170 before I noticed. The beer was drinkable, but definately had a rather harsh astringent off-taste. Hopefully yours turns out OK.