1

I re-hydrated my US-05 at 40C ( 105F ) going by this video https://www.youtube.com/watch?v=SL92Bd4kfbQ. However afterwards I read the on the Fermentis site that it should have been at 27C (+/-3). Apparently it's different depending on the yeast and I should have gone by Fermentis' instructions but would I have done any harm.

1 Answer 1

1

It's close, but I think you'll be OK. The commonly cited temp to kill yeast is about 114F. That's a generalization, but hopefully the yeast will survive. FWIW, despite manufacturer's recommendations, I find no difference between rehydrating and not rehydrating. A very experienced friend who runs a homebrew shop advises his customers not to rehydrate due to situations like yours. This experiment adds data to the point that it doesn't matter....http://brulosophy.com/2014/09/15/sprinkled-vs-rehydrated-dry-yeast-exbeeriment-results/

4
  • thanks for your vote of confidence. That video is very strange - the're actually using us-04 in the video which is supposed to be re-hydrated at 27 too. I was re-hydrating because it was a fairly high gravity beer. I heard that pitching dry ends up killing a higher percentage of cells and I only had one packet. If I had checked the fermentis site I probably wouldn't have had a problem. Wont happen the next time LOL Oct 27, 2016 at 16:55
  • FWIW, I have often pitched a single pack of US05 unrehydrated in to 1.075 wort and had no problems at all.
    – Denny Conn
    Oct 28, 2016 at 15:41
  • I've seen people report similar experiences; and other people say you're better off re-hydrate - it's funny with homebrewing talk on the web - everybody has such different experiences. I was reading a thread on us05 and half the people on the thread swore by it and the other half swore they'd never use it again. LOL. In the end with re-hydration I sort of thought it would be safer to re-hydrate - and I suppose I had little to loose if I had gone with manufactures instructions but that article suggests its a waste of time though - btw fermentis says wort needs to be above 20/68 for dry pitching Oct 28, 2016 at 18:49
  • As often happens, experience disagrees with "book learning". I have often pitched unrehydrated US05 as low as 58F and had absolutely no problems. Don't believe everything your read-even from me-try things that make sense and see what happens.
    – Denny Conn
    Oct 29, 2016 at 16:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.