[jim atlas]

What's the lowest temp that will kill yeast?  160°? 

[HoosierBrew]

More like 120F-ish.

[denny]

114 is what I usually hear quoted.

[yso191]

It depends on whether the yeast is from Phoenix or the Pacific Northwest.

[tommymorris]

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.

[jim atlas]

Code: [Select]

Wondering when it starts dying as temp raises.

[RuthanneAzia]

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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[reverseapachemaster]

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.

[denny]

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.