I'm in the process of primary fermentation for a red ale I'm doing. I pitched the yeast Tuesday night. I started to see fermentation Weds around noon and had some good krausen on Wednesday night. Now its Saturday morning and the krausen has disappeared and fermentation has slowed significantly. I'm wondering if I have a stalled fermentation? I used Nottingham Dry Ale Yeast. I know in the data sheets for the yeast it says they are fast working, but I've never had a fermentation only take 3 days. I have a second pack and I'm wondering if I should pitch that at this point, or just let it run its course? I could also take a hydrometer reading, but haven't at this point. Should I give this a day or two to see of the fermentation picks back up? Or pitch more?