Roughly 6 of my last 10 beers have fermented very quickly, but with no real krausen forming. These are all beers that I have brewed before and have seen more sedate fermentations with thick krausen. I have looked at my brew logs and can’t figure out what is different. The new ones are fermenting out in a day or two instead of 4 or 5. I have reduced my pitch rate so I don’t think I am over-pitching. I thought I might be over-oxygenating but a couple have used SNS starters and it is hard to imagine them being over-oxygenated. The latest brew was bubbling within 8 hours of pitching, with bubbles and some foam appearing around the edges. The next morning the foam was gone and the bubbling was furious and the liquid was swirling and circulating. According to my floating hydrometer it has gone from 1.050 to 1.020 in 28 hours and is still going strong. I have seen this behavior with OGs from 1.050 to 1.093 with a variety of yeasts. I had one Scottish ale that did this act of foaming a bit, then going to swirling with no foam, then after it was fermented most of the way it rapidly formed a 1" thick layer of krausen for a few hours, then the krausen dropped and fermentation was done.
If I had a stainless fermenter I wouldn’t know anything except that the beer was fermenting very quickly, but since I can see it I fret. The final result is good, but perhaps not as good as the previous ones with more stately fermentations. I am planning my next brew right now, an amber ale, and am rolling around lots of ideas on what to change but none of them seem convincing. Any suggestions?
All have been ales temperatures regulated, mostly to mid-60s. One brew was a kveik fermented at 75 and it did form some krausen but it came and went so fast that all I saw was the “bathtub ring” it left behind.
I will try lowering the pitch rate. I double-checked the temperature with a separate thermometer yesterday and it is right on. I am making the same size starters as I have made in the past, but I wonder if the yeast viability is higher and I end up with more yeast for the same size starter. I will cut it way back on the next brew and see what happens.
No, the foam was fine. I use one tablet of KICK carageenan, which is sized for 5 gallons. I was worried that there was some foam-inhibiting substance in the fermenter, so I cleaned absolutely everything as thoroughly as I could. Overpitching makes the most sense, but I just don’t quite see how I could be adding too much yeast.
Yes, the right balance in reproduction by the yeast brings out a more characterful flavor, I have found in my experience (entirely anecdotal, admittedly).
I am messing around with balancing yeast pitch with dry yeasts and pressure fermentation these days. I used to just pitch one sachet of lager yeast in a 5 gallon batch, then upped it to 3 sachets in a 10 gallon batch, then I tried two sachets in 5 gallons and liked the speed of fermentation under pressure, but the flavor seemed a bit too subdued.
I went to 2 sachets in a non-pressurized 5 gallon setting for the Koln yeast (it said to expect a lag and it was a bit slow to start, yet it finished within 10 days total) and am awaiting the results to be kegged this weekend for consumption starting next weekend. I probably will re-pitch just under half of the Koln slurry into a 10 gallon batch this weekend and aerate it well and see if it gives a good flavor.
All of this leads me to initial observations that allowing for a good bit of yeast growth is best in terms of flavor profile in the end. Or confirmation bias is creeping in…