I just brewed this up all-grain on sunday and pitched the yeast at midnight. My first home-brew.
I didn't have the DME to make a starter so I just use one vial of white labs yeast for a 2.75 Gallon batch.
The carboy is in a cold room ~15 degrees and I am insulating the carboy with towels.
For the first couple days the ambient temp outside the carboy consistently read 64 degrees F. It was a little slow to start but at 12 hours there was a thin layer of Krausen. Then there was a very thick and active Krausen and plenty of very active yeasts in suspension.
Wednesday morning we had a cold snap when I checked the carboy it was at 60 degrees and the Krausen had diminished. Today, thursday morning the thermometer is reading 59 degrees and there seems to be a lot fewer yeasts in suspension and those that are there are moving quite slowly.
Is this normal? Am I losing heat because the fermentation is slowing naturally? Or is the ferment slowing because the ambient temp is too cold and dropping? Should I raise the temperature in the room & shake the carboy to get the yeasts active again?
Here is a picture I took this morning: