I know for lagers, temperature control of fermentation is essential. I’m wondering, though, how controlling temperature would affect ales?
Controlling temp is important for any beer, to prevent the formation of fusels and unwanted yeast derived off flavors and aromas. Head retention is impacted negatively by fermenting beers too warm as well.
Edit - And welcome to the forum !
IMO, temp control is the single biggest thing you can do to improve and maintain beer quality. You can buy the best ingredients, spend hours crafting a recipe, brew meticulously on brew day. But if you can’t control the fermentation temp, all the rest will be wasted effort.
I would say it’s one of the biggest improvements you can make to your homebrew. If your house is anywhere near the high 60s, your fermentation temperature will spike into the 70s due to the heat given off by fermentation. This is bad, especially in the first 48 hours. The “homebrew” taste of unpleasant higher alcohols and phenolics is mostly caused by this, in my experience.
Yeah, this!
Thanks for the replies! I think this info pretty much determines what my next equipment purchase is going to be for my home brewery. Cheers!
+2 - proper yeast handling is close second.
I couldn’t agree more.
Controlling fermentation temps doesn’t always require a full-blown (expensive) fermentation chamber, either. I live in SE Michigan, and our home has a basement. In Winter, the ambient temp in my utility room keeps my ale pail fermenters at about 62 or so (also easy to get the wort down to that temp, as our ground water is in the 50s). In Summer, I put the fermenter in a large plastic tub of water, with a couple of frozen liter water bottles; changing out the bottles a couple of times a day keeps ferm temps in the low 60s.
I agree that #1 is temp control, and #2 being yeast health/pitchrate #3 is water pH/Alkalinity. But I am still newish to the hobby/passion/addiction/dare I say way of life.
Some ale yeasts perform best at particular temperatures, so you get the best from them if you can control temperature. Low temperatures better for clean tasting beers, higher for beers made with expressive Belgian or British yeasts.
You can also raise temp at end of fermentation to help yeast clear up fermentation by-products like diacetyl and acetaldehyde, and then chill to clear the beer.
Extremely useful all round for ales as well as lagers.
One of those questions I have hesitated to ask (“I should know this by now”) is whether I should set the the temp of the fridge a few degrees lower. In other words, if a recipe says “ferment at 68 degrees F,” is that the wort, or the ambient temperature?
It’s wort temp that matters.
If you don’t have a thermometer in the wort, is there a rule-of-thumb offset?
Get one of those stick-on liquid crystal type thermometers, they’re a great way to measure fermentation temps accurately.
And FWIW, I’ve had good results fermenting at ambient temps-but note that I typically brew British styles that benefit from fermenting a little warmer than American styles. Also, the beers this has worked with never got warmer than 66oF, as measured by a thermometer as described above.
I have used those stick-on thermometers on previous carboys, but always wondered if they were measuring the wort temp all that well. I suppose better than just guessing, but particularly with buckets, are they getting at the thermal heat created deep in the burbling depths of fermenting wort?
As turbulent as fermentation is, I’d assume things are within a degree or two of uniform.
For temp controlled fermentations, I know myself and others usually just tape the controller’s temp probe to the vessel and cover it in some sort of insulation. If measuring the temperature through the wall of the fermentation vessel wasn’t close enough, I think we’d know it.
That’s easy enough – thanks.
But while you are planning that equipment purchase, don’t discount the plastic tub of water approach for ales like leejoreilly suggested. Last summer, with daytime temps here around 90, I put a fermenter in a tub of water, put an old t-shirt on it to wick the water and aimed a fan on low at it. It kept the temp below 70 all day. Turned the fan off at night.
Nope…we discussed this on the last episode of the podcast. There’s really no way to calculate a consistent offset. Best thing to do is stick a Fermometer on the fermenter. They’re remarkably accurate.