StarSan becomes yeast food?

[8rnw8]

Hello all. I've heard from a few different sources that starsan breaks down into yeast food. My question is How does the starsan differentiate between "good" yeast and "bad" yeast, as well as other wort gobbling nasties? It seems like something that breaks down into yeast food so quickly would not be the greatest sanitizer. For the record, starsan is all I use. I just want to understand how it can be sanitizer, and yeast food.

Thanks! If this has already been answered, please feel free to post a link. Found bits and pieces, but nothing that directly answered this question.

 

[MalFet]

It's not exactly that StarSan breaks down. Properly kept, StarSan will stay good for long periods of time. StarSan is an effective sanitizer because it is a strong acid. Once the concentration drops past a certain point (i.e., when it gets mixed up with 5 gal of wort) it ceases to have the same active properties. That's what makes it a great food-safe sanitizer.

I'm not sure what people mean by" yeast food" exactly, but I suspect they are referring to the fact that dilute StarSan is a source of free phosphorus, which is an essential macronutrient.

 

[Airborneguy]

I believe this was mentioned in a Basic Brewing podcast by the creator of Starsan. From what I remember, it was brought up more as a reason to not worry about getting it all out of your fermentor than anything else.

 

[Starderup]

No yeast food could differentiate between good and bad yeast. That's our job to make sure the right ones are in there.

 

[8rnw8]

Thanks everyone, that makes a lot more sense. I'd heard "don't fear the foam", but didn't understand the in's and out's.