On Labor Day I brewed a dark stout. I played with a partial mash, it was really not much more than steeping grains, but I added some stuff to my distilled water to get used to worrying about water chemistry. It was kind of silly because I had no pH meter to use, and my grainbill was very small with lots of water, so hopefully I didn't do more harm than good. It was also my first full boil, I started at 4 gallons and boiled down to 3. I also had my first boil over shortly after adding the DME (first time not using liquid extract too), but it wasn't too bad as this was also the first time I brewed in the garage with a turkey fryer type setup rather than on the kitchen stove.
All that was fine. Since I only had 3 gallons, I thought it would be better to use my 5 gallon glass carboy to ferment in instead of the larger plastic bucket. I got up to about 1.066 when all was said and done, and I tossed in some nottingham WP039 yeast around 9 PM and 70F. When I came home from work for lunch on Tuesday, I was impressed with the vigorous fermentation - temp up a little to 71. The airlock was all bubbly and there was a generous layer of trub on top. Today at lunch, it was much the same story, but it was 75F. Nice evidence of fermentation, but perhaps a little warm for this yeast. I have a blanket around the fermentor to keep light out. Tonight though, the bubbler is rather calm in comparison. All the trub appears to have dropped out of site, and temp is back down to 72.
I've never seen the fermentation before, is it normal for all the bubbles on top to drop down after just a couple of days? I suppose gunk gets pushed to the top and when it hits a certain density it just drops down. I just wanted a sanity check. This is normal, right?