I brewed a black rye IPA, all grain, on 12-1 with a SG of 1.077. I used pacman yeast and kept the temps around 65 degrees for the time that is was in the primary fermenter (until 12-20). Which was 19 days. Transferred to a carboy and the gravity at racking was 1.009. Now today, on January 11, (three weeks in the secondary) I noticed foam in the carboy. The temp has risen to 68 degrees over the past two days where it had been around 60-62 for the past three weeks. This is my 10th ag batch and I have brewed about 50 total. I have never seen this happen. There was no foam at the first of the week. What could be the problem? I am very careful with sanitation but I realize that anything can happen.