My power went out and I guess the house cooled enough during that time to suck about 1/4 gallon of sanitizer from the blowoff into my 1 gallon batch mead. It completely filled the headspace and started to climb up the tubes on my 5 gallon batches of beer.

There seems to be no more yeast activity in the batch, so I'm thinking it must have all died off from the sanitizer. The gravity is still high so I want to ferment this further, but is it pointless to repitch some new yeast?

If I repitch the yeast and it takes off again, will it be safe to drink? Will it even taste good?

The sanitizer is Star San.

1 Answer 1


Starsan is safe to consume once diluted to the recommended concentration (1 fl.oz/30ml to 5 gallons/20 liters.)

A quart of starsan in 5 gallons would not kill the yeast - made up starsan has a pH around 2.6-3.0 depending upon your water hardness. Once diluted in 5 gallons of beer, the starsan is diluted a further 20 times. (1 quart in 5 gallons.) That would raise the pH of the starsan to 3.9-4.3, giving a overall pH around 4.6, assuming a beer pH of 5.0. (These are just back of the envelope calculations and the pH may well be even higher.) While 4.6 is on the low side for a beer, and it may taste a little sour, the yeast will happily continue to function down to pH 2, so they'll continue if they haven't already finished. (Wine and mead regularly have pH in this region.)

The title says mead, but the question talks about beer. If it is mead were talking about then this may even help provide a little "bite" to the flavor of the mead, if you've not already added acidifiers to the batch.

If you find the batch to be too sour, you can add some glycerine to balance out the tartness with some sweetness.

  • I did taste it, and it was still pretty sweet as it hasn't completely fermented out yet. I will let time tell the tale of this mead. I took a few gravity readings and it has been very slowly dropping, so it looks like the yeast is still working.
    – jsmith
    Jan 28, 2013 at 13:21
  • If I'm reading the question correctly, the sanitizer was sucked up into a 1 gal batch of mead, not a 5 gal batch of beer (there were multiple tubes going into the same sanitizer). 1 quart into 1 gal will probably be noticeable...
    – Bob
    Feb 16, 2013 at 17:58
  • I did misunderstand that part, and I agree, it will be noticable! However, I don't think even at that concentration it will kill the yeast, since it is still relatively diluted (1 quart starsan in a total of 1-1/4 gallon liquid, so 5x diluted), so fifth of the usual sanitizing strength. I think the impact on taste will be the bigger issue.
    – mdma
    Feb 16, 2013 at 19:54

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