So i just brewed my First Chocolate Oatmeal Stout and pitched 1pkg of S-04 yeast. The brew started bubbling up at 12hrs and continued for 36hrs. Is this normal for a Stout The temperature has been stable around 72F and did not see much of a head. The OG was 1.070. I was going to wait about a little over a week to take another gravity reading, but was not sure if this is how this type of yeast works. Any help.