Beer Forum

I don't think it matters, but . . .

I oxygenate with an aquarium pump and airstone. Every once in a while, I'll get distracted and leave and come back to find that some of the foam from the aerated wort is coming out of the carboy.

Am I losing any essential contributors to flavor or aroma from this?

Possibly some head-forming proteins, but I really wouldn't worry about it unless you're noticing a problem in the finished product.

drop some fermcap-S in there, "poof," no more foam.