I'm assuming an infection

So, I've spent the past two months on my most complex beer-brewing journey ever. I did a cereal mash for the first time and used a my first sour mashing technique in the same beer. Add to that same brew, one month on some fruit, and I've got a ton of time and excitement tied up in this one sweet/sour peach beer. I'd hate to think of it all going to crap.

After having it in secondary on fruit for a month, I transferred it to tertiary yesterday. Actually, I transferred it to a sanitized holding bucket, cleaned out the carboy, sanitized the carboy, and returned the beer to the original carboy. This evening, I checked in on my project only to notice two things 1) my airlock had had a "suck back" and almost all of the sanitized water inside of it was gone and 2) I had a smooth, thin, off-white film on the surface of the beer. What's odd is that I used the exact same equipment on the sister brew (only sitting on berries for the same time period) and there is no film there.

So A) do I have an infection or is this yet another odd at first but normal occurances in beer making?

B) Since this is supposed to be a sour beer to begin with, I'm assuming I'll be OK to bottle. Should I increase my tertiary time to let this "infection" run it's course before then?

C) Why, oh why did this have to happen to THIS batch? The batch I've been planning for the better part of a year (had to wait until fresh Georgia peach season!)

PS My digital camera is on the fritz, btw and can't take pics or else I would post a look-see.

You know, I had almost exactly the same thing just happen to me on a recent batch of strawberry blonde a week or two ago, only I went from secondary straight to bottle. Mine looked like a lactobacillus infection.

For what it's worth, I tasted mine and it was absolutely phenomenal. No sourness; just a really crisp, clean flavor. By far the best batch I've made of that beer.

EDIT: I had also added gelatin and then cold crashed, but I seriously doubt that was a layer of gelatin on my beer.

Those plastic S curve airlocks are little more than a dollar at my LHBS. When filled to or below the line they give a plenty adequate air seal, and don't have enough fluid volume in them to allow the fluid to suck back past the widened areas (the "bubbles" on the S). If the fluid is a sanitizer like StarSan or even cheap vodka the likelihood of pulling live bacteria through the S is very low. These sanitizers don't last indefinitely (StarSan shouldn't get direct sun exposure for long, alcohol evaporates, etc) and would require the occasional change--if you anticipate more negative pressure in the carboy. That should only be an issue if you are cooling the carboy with the airlock in place. I suspect your carboy was warm from the cleaning, and cooled with reintroducing the beer, causing the negative pressure.

It would really help us help you if you took a picture.

Revvy - I know it would. I'm working on it.

Weirdboy - It's very ironic you bring up the gelatin. I too used gelatin (brought water to a boil for 5 minutes, let cool to 150, added gelatin, added mixture to beer while racking to tertiary) on this batch. I hadn't even thought about it, but it could be a thin layer of gelatin on top I suppose. I've never had that happen before, but it is a thought.

Any ideas on this possibilty folks?

dont worry. its fine. drink more and you'll forget.

I wouldnt worry, its just beer.

Worry might be a bit strong for my feelings towards this. But I am very disappointed. I've been waiting and preparing the better part of a year for this one batch and I've never had an infection before. What a crappy time to have it happen.

But as you say, it's only beer.