somedudefromguam

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Will lactobacillus denature at standard mash temperatures?

GuldTuborg

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Well, lacto is an organism, so it will not denature, but it can die. At what temp it does begin to die off is very strain dependent, but I would not expect it to die off at standard mash temps. Even if you sparge hot, I wouldn't bet on 100% death rate. Does that help? Why do you ask?

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blizzard

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Leaving your mash for a day or two is a good way to get a sour beer (look up sour mash), primarily from lacto. So no, the mash won't kill it.

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Calder

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You will kill it with boiling. Probably 170 will do it, maybe even lower.

Would like to know why you are asking so we can tell you if you have a problem. If you want to mash overnight, you might be OK. Lacto has a lag period before it starts working where it acclimatizes itself to it's environment. Seems to be somewhere between 10 and 60 hours ...... however, as soon as someone takes my advice they will find the perfect environment for Lacto, and it will take off immediately.

There are other bacteria in the mash, which might start working quicker and produce undesirable results.

somedudefromguam

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Very interesting responses, thank you.
I am actually doing a sour mash right now, and I usually use about a half pound of uncrushed malt to get the lacto started around 120F. I was short on pale malt, but I am going to boil a half pound of sugar to make up for the lost gravity points.

ReverseApacheMaster

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It will start to die off around 130F but definition dead by pasteurization temperatures.

somedudefromguam

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Good to know. I wondered why the recipe called for an extra half pound of grains pitched back into the mash after it cooled...

smokinghole

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The reason for the additional grain was to give the mash a source of fresh undead bacteria on the extra half pound. I've never done a sour mash but I think you do a normal mash conversion rest then you cool it down to about 110F or so and add the unmashed grain. This gives you full conversion in the correct pH range and then souring before boiling.

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