Last night, I put my 1.130+ (it wasn't until midnight when I finished that I noticed that it was higher than my hydrometer and refractometer could go) wort in the carboy to ferment. I wake up this morning, and as to be expected, it's going absolutely nuts, near filling up what was already a half full gallon jug of water + star-san for my blow-off.

It's hard to tell as there's so much blow-off in it that it nearly matches to the color of the carboy itself, but it looks like there's somewhere between a 1/4 - 1/3 gallon of yeast at the bottom of the jug. I was wondering if it were possible to wash and can off that yeast? Is it not worth it given what's going to be at the bottom of the carboy in a week after primary has finished? As stated above, it was about 1/2 - 2/3 full of tap water and star-san before fermentation began.

  • I expect that the high acidity level of the Star-san probably isn't good for the yeast, but I'm interested in a generic answer to this question. What gets in the blowoff is similar to the krausen, and thus this would be similar to top-cropping, no? Commented May 19, 2013 at 20:35
  • At this point, I've already had to replace 2 gallon jugs used for blow off, and since I only have two available, I've opted to just dump the yeast. Plus, I don't have the need for all that yeast, so I'll gladly settle for what remains in the bottom of the carboy after fermentation completes. Despite all that, I am still interested to hear if star-san has any adverse effect on yeast and whether or not this is a safe practice.
    – Scott
    Commented May 19, 2013 at 20:49
  • related: Does starsan kill yeast
    – mdma
    Commented May 20, 2013 at 13:59

1 Answer 1


I think that dumping the yeast is best.

However, the yeast collected from blowoff is the best yeast for repitching as it has not been stressed by high alcohol levels. It's very much like top cropping in that regard.

With your setup I'd worry about two things: the effect of StarSan on yeast viability, and contaminants that may be in your tap water. If you want to reuse yeast from blowoff, you could built e homebrew equivalent of a Burton Union System. BYO has a good writeup on a DIY version. This collects blowoff in a sanitary manner making it safe for reuse.

  • Awesome link! I'm definitely going to have to try that for some of my future brews.
    – Scott
    Commented May 21, 2013 at 14:38

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