The "point" of temperature control

Post #1 made 4 years ago
First, a preface as this is my first proper post. From reading these boards it seems this place is very up for challenging received wisdom and superstition when it comes to brewing. Hence I have posted this here rather than other forums as I am aware the thread title may come across as slightly inflammatory but I am trying to understand the parameters and real goal behind temperature control of fermentation as it relates to fermentation activity.

Most information I have seen is of the "you must control fermentation temperature or you will not get good beer". Clearly this is not true - you may still get good beer. You are unlikely to consistently produce good beer and this is fair enough and likely true.

My case in point - I am currently fermenting an pale English style ale with S-04 and it is the dead of winter here. This is my Sixth brew total (fifth AG) and first time making even the most cursort attempt at temperature control, wrapping the fermenter in a sleeping bag. The brew started out around 15C and peaked at just over 17C two or three days into fermentation. We had a cold snap Monday into Tuesday (outside ambient temps dropped to -5C) so when I got home from work on Tuesday evening the temperature of the beer had dropped to 14C. However, I do understand that it is better to be on the low end of a yeasts recommended temperature range and also that S-04 is quite a forgiving yeast so I am in no way panicking.

So the meat of the issue - is the point of temperature control to maintain as close to a precise, constant temperature as possible or to keep within the yeasts recommended operating temperatures, whether manufacturer advertised or established through experience? I am unlikely to be getting any more sophisticated in the near term when it comes to temperature control so this will probably affect the degree to which I am fussing over the fermentation (eg. last night I had it beside a radiator to bring temp back up to 15.5C before tucking it up again).
Last edited by DaveGillespie on 15 Jan 2014, 20:47, edited 2 times in total.

Post #2 made 4 years ago
There's no simple to answer to that one... This is a decent read I think: ... m-the-pros

You can do easy things like putting your fermenter in a warmer spot, or a spot with a more consistent temp ie. not in a windy hallway. A heating belt or similar would be pretty cheap, and easier than mucking around with a radiator. Insulation helps a lot.

Your big issue might be in summer, as high temps can produce off flavours... In Queensland, we pretty much always need a fridge to ferment in.
    • SVA Brewer With Over 50 Brews From Australia

Post #3 made 4 years ago
Well, I had intended to brew a Hefeweizen (first attempt at this a couple of brews ago did not go well at all) next but having thought about this I will probably leave that until the summer when the ambient temperatures will be more suited. I'm in Northern Ireland and we would rarely see temps above 22-23C but ambient temperatures in the summer should be good (as far as I understand) for a Hefe in the upper "Banana" type range.

Brewbelt and temperature controller might be doable.

Post #4 made 4 years ago
Well I see you won't have to worry about a fridge!

Sounds like a decent plan to brew styles according to the seasons.

Things like stone/brick walls or floors with a good thermal mass can help regulate your brew temps as well.

Other than that, heating for brewing is not my forte!
    • SVA Brewer With Over 50 Brews From Australia

Post #5 made 4 years ago
Everything I have researched seems to indicate that the first 24-48 hours of fermentation is when temp control is critical. I have a dedicated upright freezer that has been converted to a fermentation chamber with a digital temp controller allowing me to control fermentation temps to with 1-2 degrees. That being said, I have played around a bit with known recipes at different fermentation temps and can state that (anecdotally at least) there is a marked flavor difference between fermenting on the low end of a yeast's range vs the high end....especially with a Hefe yeast (clove vs banana).

    • SVA Brewer With Over 100 Brews From United States of America
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