I will be purchasing a Fermometer before I brew my next batch. However, for this first batch, too late. Question, if the ambient temperature is 60 degrees, what do you think the fermentation temperature is? Does this vary with different strains of yeast and/or different styles of beer? Thanks in advance!!
Yes, it will vary with yeast strain. Also with the original gravity of the beer (higher = warmer). Also with batch size and fermenter geometry. At peak fermentation, the difference could be anywhere from a couple of degrees to more than 10 degrees. I've seen 12 degrees (maybe more one time, but my notes aren't handy) in a big imperial stout.
I think 5 degrees is a good, safe number to assume during fermentation. And honestly, unless you are looking to get super specific about flavor profile, a couple of degrees here and there doesn't make a difference.
That is a fairly moderate OG value and based upon my brewing history I would expect the temperature of the fermenting beer to be a few (e.g., less than 5) degrees warmer than ambient. So if my ambient temperature in my basement was 60 degrees F I would expect that the reading on my fermometer would not exceed 64 degrees F. I should caveat that I place my primary fermentor (plastic bucket) on a concrete floor and that concrete floor somewhat acts like a heat sink. Maybe if the bucket was on carpeting the fermentation temperature might be a degree or two higher? Anyhow for a typical ale fermentation you likely should not be concerned about the fermetation temperature being too high. Unless I am fermenting Belgian Trappist/Abbey Ales or Saisons I typically target something like 68 degrees F for ale fermentations. Cheers! P.S. I do ferment hybrid styles (e.g., Kolsch, Altbier) on the cool side (60-62 degrees F).
For a given fermentation setup the temperature difference will primarily depend upon the rate that the yeast produce alcohol (and thus CO2). A bigger beer will likely have a bigger rise owing to the increased sugar concentration, which leads to faster metabolic activity by the yeast. It could be that different sugar composition has some effect, but that is outside my domain of expertise, and so just speculation on my part. Cheers!
FWIW that has been my consistent experience. When I have brewed beers with higher OG values (e.g., Quad, Tripel, Robust Porter,...) the rise in fermentation was larger (e.g., > 5 degrees F). There may be other factors which yield large deltas in temperature but for me OG value was the significant variable. Cheers!
I think generally fermenting at 60 ambient as safe. I routinely set my fermentation chamber to 60 with the probe attached to the side of the fermenter with a piece of bubble wrap for insulation.
I’ve fermented many types of beers both high and low og. I now typically make wild ales. Fermented in 10-20 gallon barrels. Ive always fermented at ambient temperature in my basement which is around 65-70 depending on season. Most types of beer / yeast haven't raised the temp of the beer more than 5-6 degrees. All with great results. Lagers i have found “create” more temperature so I ferment cooler around 50 to try and keep the fermentation temp down
