Hello! So this is a kettle soured beer brewed with brettanomyces bruxellensis. It's been through primary fermentation, at which point it had some pretty big yeast rafts. now it's been in secondary fermentation for five days, and I noticed this growth on it. I don't know if it's more yeast rafts, but I'm more concerned because this is secondary, not primary, and because it covers the entire top of the beer. It does not smell bad (through airlock) though, so I'm hoping it's not mold. If it is mold, will it be salvageable?