Stupid mistake... is the batch lost???

What kind of sanitizer? I would keg, taste, and evaluate. Don't dump it without tasting it first, it's not like you're investing alot of time into bottling.

 

Honestly, I have made the same mistake. Cold crashed before swapping from blowoff tube to airlock, and roughly 16 oz. of Star San was pulled back into the carboy. I used gelatin in the keg afterwards to promote clearing just in case. I was fearful that it would be ruined, but it was not detectable at all.

 

Keg it and taste it. It'll probably be fine.

 

If the starsan was still at a sufficiently low ph nothing should get in and you shouldn't even notice the difference. If you had a lot of krausen dump out into the blowoff container it might have been enough to raise the ph to where unwanted stuff could occupy the blowoff container and when sucked back into the beer been brought in to the fermentor.

 

How did the jug look? Anything strange (other than blowoff yeast) growing in it? If not, you're probably okay, although a half galllon of solution into a 5 gallon batch is going to change your flavor/aroma/bitterness/mouthfeel/etc. a bit.

How far below your fermenter was the blowoff jug?

 

One of my highest rated beers was about 1/6th star san when I racked on top of some left in the carboy by accident. I'd guess you'll be fine!

 

I always put the blowoff container much lower than the fermenter, to discourage suck-back from being able to create a reverse siphon.

 

Yeah that sucks, but I'd taste and smell it. Star San is supposed to be pretty safe even in decent amounts. There have been several tests done where guys have racked their beers right on top of layers of star san and the beers have been fine. I doubt you'll have to dump the batch.

 

I'd be interested in reading about those if you have links. I know that what's-his-name from Five Star has said that you could 'probably' ferment a batch with half of the water actually being starsan solution, but did not know there were tests.

 

Sure, let me see if I can pull up some actual articles or quotes. Probably a lot of my recollection on this topic is other brewers trying the same sort of thing, but I thought I remembered some research being done on the subject as well.

 

That being said, I've never tasted that high of concentrations of Star San. While I have no doubt your beer could ferment and finish fine on Star San, I don't know how that would affect the flavor and smell.

 

Star san is soap solution with a low pH via Phosphoric Acid. I would say the batch is safe from a chemical point of view, but perhaps not from infection depending on what was growing in there.

I have never used starsan btw.

Since you are kegging I would proceed as normal, kegging and keeping cold immediately to keep any infection at bay. Or use some preservative to kill off the organisms. If it tastes like soap then it is up to you if you like that or not.

 

The first beer event I went to a long time ago had a 5 Star rep touting the benefits of star san. He asked for volunteers, and got 3 or 4 on stage. One of the event organizers was sent to the hotel bar to bring back beer samples. Each glass (can't remember the size, at least 10 oz.) had straight star san added, maybe a teaspoon. The only one the volunteers could say some thing was off in was a glass of Guiness, and they agreed that it look like a lot of the star san was caught in the dense head. I now one of the guys on stage, he is a BJCP National judge, and knows the taste of beer.

You will be fine as far as the star san goes.

 

To drive this point home further, a MSDS for dodecylbenzenesulfonic acid. Keep in mind this is for a 100% solution, no idea what star san % is but after putting 1oz in 5 gallons I bet it alot lower than 100%, which is 100 grams in 100 ml total of solution.

The dose that will kill half of you is 650mg/kg. Given a 200lb human you need 58 grams. So even if you had the 100% concentrate you would need to drink 58ml. Good luck choking that down.

Specific gravity of the 100% dodecylbenzenesulfonic acid is 1.060 and starsan is listed at 1.320 which makes absolutely no sense to me. Maybe star san is a 500% solution but that is unlikely since Sigma sells a 70% solution in Isopropanol. Since they use Isopropanol that is an indication it is not as water soluble at higher concentrations as one may like.

/geeky ramble

 

If it is getting worse, that is not the amount of star san increasing. Just saying.