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General Category => Yeast and Fermentation => Topic started by: jim atlas on September 24, 2016, 02:32:38 pm

Title: Kill temp for yeast
Post by: jim atlas on September 24, 2016, 02:32:38 pm
What's the lowest temp that will kill yeast?  160°? 
Title: Re: Kill temp for yeast
Post by: HoosierBrew on September 24, 2016, 02:34:40 pm
More like 120F-ish.
Title: Re: Kill temp for yeast
Post by: denny on September 25, 2016, 09:41:53 am
114 is what I usually hear quoted.
Title: Re: Kill temp for yeast
Post by: yso191 on September 25, 2016, 09:57:24 am
It depends on whether the yeast is from Phoenix or the Pacific Northwest.
Title: Re: Kill temp for yeast
Post by: tommymorris on September 25, 2016, 12:38:21 pm
Is your goal to pasteurize or are you wondering when yeast starts dying as temp increases?

Pasteurization kills all the yeast rather than some. So their is a recommended temp and time at that temp to achieve pasteurization.
Title: Re: Kill temp for yeast
Post by: jim atlas on September 25, 2016, 07:05:28 pm
Code: [Select]

Wondering when it starts dying as temp raises.
Title: Re: Kill temp for yeast
Post by: RuthanneAzia on September 26, 2016, 03:18:52 am
So what is the recommended temp and time for pasteurisation to kill all yeast? I'm aware of temps needed to kill spoilage microbes, but is the required temp lower for just brewing yeasts?


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Title: Re: Kill temp for yeast
Post by: reverseapachemaster on September 26, 2016, 09:05:26 am
Saccharomyces cerevisiae is more heat tolerant than many other yeast. Around the mid-100s they will stop reproducing but live cells will survive much higher temperatures. Most bacteria will die off with relatively short contact times with temperatures in the 120s to 130s.

Heat alone isn't enough to kill off yeast (or bacteria). It is a combination of heat plus contact time. Normal pasteurization techniques for food is in the 160s for 10-15 minutes because that is a sufficient level of heat for the requisite time to kill off most food spoilage organisms (including yeast). Mashes are typically hot enough for long enough to kill off most organisms although you aren't getting into the 160s during the mash. A simple flash of heat isn't going to be enough unless the heat is so hot that the necessary contact time is minuscule.
Title: Re: Kill temp for yeast
Post by: denny on September 26, 2016, 10:46:36 am
So what is the recommended temp and time for pasteurisation to kill all yeast? I'm aware of temps needed to kill spoilage microbes, but is the required temp lower for just brewing yeasts?


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Pasteurization temp is 160-165 for at least 10 min. IIRC.