First Infected Batch

Question

I have been brewing in 5gals for years and have had no problems making this ESB. I have been using 5gal glass carboy's up until this point, and the Grainfather system.

We have never had an infected batch, however we just tried to make our first 10gal batch using a 14gal stainless steel Chapman fermenter and the batch is infected. We did add some extra non-boiled water at the end, but other than that, everything was properly sanitized as normal and the recipe was followed as normal (except we doubled the recipe for 10gal).

Did it get infected because of the 4gals of headspace in the new fermenter? Or did we do something else wrong?

Note, there was some extra lag time to start seeing action on the airlock (about 12hrs), which was longer than I normally see action. It also appeared to last about 4 days hard instead of the normal 2. Also, I think I pitched the yeast a little hot (like 88deg).

Answer 1

That really sucks but sometimes it happens. I've dumped a couple batches over the years because they just didn't come out right. No idea what went wrong. I do regularly brew 4 gallon batches in 6.5 gallon fermenters and haven't had any problems yet. I too have a chapman fermenter and love it (glad to hear you ditched the glass carboys. Those things are widow makers).

I would guess the high temp pitch is likely the culprit and the un-boiled water may have introduced some extra unwanted microbes. 88F is pretty warm unless you're pitching Kviek. The yeast likely got knackered and couldn't get a decent ferment going. Something else got started munching on it first.

We don't brew in sterile environments so despite our best efforts there's still stuff getting into our wort. Healthy yeast will usually out-compete these things though if we can keep the additional microbes to a minimum and maintain an ideal environment.

Hope the next batch turns out better!