Author Topic: Accidental temp jump in mash  (Read 1599 times)

Offline jbnola

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Accidental temp jump in mash
« on: September 05, 2019, 03:05:41 PM »
My friend and I recently brewed a NEIPA. Our grain bill consisted of 9 lbs Rahr 2-row, 3 lbs flaked oats, and 2 lbs flaked wheat. We were targeting a mash temp of 154-156. We stayed in that range for the first 15-20 minutes. Then we had some issues with the natural gas burner we were using to heat the mash tun. Very quickly the temp jumped up to almost 190. We killed the heat, stirred like crazy, and added handful after handful of ice until we brought it back down to the desired temp (this took about another 15-20 minutes). From there we continued to mash at the proper temp for another 30 minutes. Using the iodine test, it seemed that conversion was completed, so we continued with the brewing process and in the end we got it in the fermenter and pitched the yeast (the OG was around 1.058 or so when we were targeting 1.068). There was quickly bubbling action in the airlock, but after only a day, no more bubbles. Do you have any thoughts about how this beer may turn out? Will it be overly sweet? Will it be low ABV? Most importantly, will it be drinkable???

Offline Oginme

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Re: Accidental temp jump in mash
« Reply #1 on: September 05, 2019, 05:16:39 PM »
The good news is that the majority of the conversion takes place in the first 15 to 20 minutes.  Once you hit 190 F, the conversion was essentially stopped as at that temperature the enzymes denature very quickly.  Since you did an Iodine test which came out negative, your conversion was complete.

So you may end up with a much higher FG than you had planned and that may end up being a little sweeter than you had anticipated, but if you have enough bitterness from the hops you should end up OK.  Different from what you wanted, but OK all the same.  Finish it out, bottle or keg it and give it a try.  Either way, it will be beer!

As far as your airlock activity, following bubbles in your airlock one of the most misleading indicators of fermentation progress.  Give it a few days, check your gravity and then give it a few more.  If the gravity measures the same over the course of a few days, then the fermentation is most likely done.
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Offline BOB357

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Re: Accidental temp jump in mash
« Reply #2 on: September 05, 2019, 05:26:14 PM »
About 170 degrees denatures the alpha enzymes in 10 minutes or so. In the 190 range I would expect they were long gone by the time you got the temperature down. Without that amount of flaked grains I would expect conversion to be close to complete in 15 minutes, but the flaked grains would have diluted the enzymes quite a bit and thus slowed conversion. I'd expect a fair amount of unconverted starches and a fair amount of non fermentable sugars to be present in the wort. It wouldn't surprise me at all if the yeast consumed the fermentables in a day or so.

 You might get lucky, but in a style like NEIPA, I doubt it.
Bob

Offline dtapke

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Re: Accidental temp jump in mash
« Reply #3 on: September 06, 2019, 09:18:51 AM »
I say F-it, dump some gluconase enyzemes in there and let it overattenuate to produce a "Brut NEIPA"

boom, new style is born. :P

but seriously, more than likely you'll be fine, give it a taste test, if it's too sweet, add some enzymes and see what happens.
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Offline Oginme

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Re: Accidental temp jump in mash
« Reply #4 on: September 06, 2019, 09:31:11 AM »
There are a couple of things working in your favor.  First, you have a lower gravity than predicted, which means that your isomerization of alpha acids from the hops will be just a bit more efficient.  Next, with the lower starting gravity, even if you end up with a higher final gravity, it would not be as sweet as it would be had you hit your intended target.  Overall, I am guessing that it will balance back out and not be coyingly sweet.  Like I said before, not what was intended but most likely drinkable.
Recycle your grains, feed them to a goat!