This is not what I had in mind for a white Christmas… I had a 5 gal batch of NB Dawson’s Kriek in a secondary carboy for several months and just never could get around to bottling or kegging. So today my daughter and I went to keg the batch and we discovered that the airlock had dried out and there was a white film of mold on top of the beer. Last time I checked the beer looked fairly clear and light brown in color with nothing on the surface, now it’s dark brown with a white moldy film on top. I was set to dump the batch, but then I opened the carboy and took a whiff. Actually smells OK, and we took a sample just before going ahead and kegging anyway. SG had dropped from 1.012 to 1.007, it tastes sour with a hint of the cherries, kinda like a lambic should, I guess? (This is my first one, I mostly brew lagers and wheat beers). I had a few sips a while ago and I ain’t dead yet, so I’m guessing this batch might be OK and actually drinkable with further aging in the keg. Or am I missing something? How sour should the Dawson’s Kriek turn out, and is a dark brown color typical? Should I just dump the batch and start over?
This isn’t an answer, but if I may, I’d like to follow up and ask what are the general signs of a batch gone south? It’s tough to tell when the whole process is new.
What you see on the top may be a pellicle, not a bad thing at all in a lambic. You lambic blend has bugs in it besides just yeast. Even if it is mold, that doesn’t always signal the kiss of death for a batch.
My recommendation - carefully rack underneath the layer on top, stopping the transfer before you suck up any of that stuff. If the resulting beer smells and tastes okay (bearing in mind that sourness and a certain degree of funk is normal in a lambic) you can either keg it immediately, or give it some time to verify if the stuff is not going to grow back. Cold and the lack of oxygen should inhibit further growth, so putting it in a purged keg is a good idea.
That white film is likely a pellicle from the Brett in the lambic “bugs” for the kriek. This is perfectly normal, and even desirable. In fact, the pellicle is probably keeping acetobacter from taking over since the airlock dried out. If it is a pellicle, I’d just top off the airlock and wait until the pellicle falls in on its own.
Thanks for the replies. I did rack to a 5 gal keg being careful to not get any of the white stuff and still ended up with close to a full keg. I put in the refrigerator and will keep cold for a while and see how it turns out. If I remember I will post a follow up in a few months. Thanks again…
