It is probably a clump of yeast
- "It's all about time. You can't rush perfection. Time TIME TIME!!! You either need to pay on the front end or the rear. If the batch ferments out fast you need to secondary age or bottle age it. If it ferments out slow... months not weeks, then you don't have to age it nearly as long to get good flavors. Either way time is the key when making ciders and wines."