Cold Crash sucked all of my star san solution into the fermenter...

I forgot to switch out my blow off tube with an S lock and, while cold crashing, 1/2 gallon of star san solution (which comes out to .1oz of star san) got sucked into 13 gallons of beer.  Is that enough to ruin the batch?

Probably.  But I’ve also had some that were just fine.  Did you change the solution for cold crash or use the same solution that was used for fermentation blow-off? If the former you have a chance if the latter you are probably screwed…sorry.

Dave

Bummer.  There is no reason to use more than just enough to cover the very tip of the blowoff hose.  Some would drink it.  I would dump it.
Edit: if you’re going to keep it, please be ethical and let people know it is 4% sanitizer solution before serving it to them.  Having to state that would be enough for me to dump it.

I think that your beer is probably okay. If you do the math, .1 oz. of Starsan in 5 1/2 gallons of beer is a negligible amount. RDWHAHB!

This has come up before so you’re not the only one.

I’d be more concerned about the nasty blow off water than the star San. Especially after a week or so sitting in a blow off bucket.

When it happened to me, there was a layer of the starsan on top and the beer below. I carefully racked the lower beer to a keg. It won a medal at a competition.
So just wait and see. It might be fine.

This is what I was trying to say.  The StarSan is inactive at this point and week old blow off water will have some bacteria for sure.

+1
This also is my experience. I racked from underneath the StarSan and it was delicious.

I use vodka or whisky in my airlocks…booze does not go inactive…and suck back, while undesirable is not gonna kill you…