Cold crashing=back flow?

So I cold crashed for the first time this week and noticed my blowoff hose was full of beer and my blowoff container was lower today than last night. The container had star San and beer from the fermentation. Should I be concerned and if so what should be looking for?

 

Yes... The cooling of the warm liquid in the fermenter creates a vacuum and sucks up the blow off liquid.

Don't cold crash with a blowoff attached.

 

Yep, lesson learned. Now will it ruin the batch?

 

If I had to guess maybe a cup or two. But it was diluted going back in from the earlier overflow.

 

I won a silver medal on an Apricot Cream Ale that sucked back 2 cups of StarSan. RDWHAHB.

 

I also had a beer that sucked up a couple of cups of Star San into a 3 gallon batch. It turned out fine and was probably one of my better beers at that point.

I still use a blowoff during cold crash but I switch my bottle to a White Labs vial with just enough Star San to submerge the end of the tube. If it's a small enough amount of Star San, it will break the vacuum before it gets sucked into the fermenter and return to the vial.

 

Thanks for the reassurances and feedback!