There is a lot of discussion regarding keeping fermentation temps to the cool end of the yeast’s range to avoid esters, fusel alcohols, etc. from forming. I have been using yeasts with lower temp ranges to try to avoid this and so I don’t actually have to keep the fermenter warmer (I keep my house in the low 60’s in cold months of the year). However, I have noticed that peak fermentation, being quite an exothermic reaction, can push temperatures in the upper 60 degree to sometimes low 70 degree range all by itself even in an ambient temperature of low 60’s. Is this a concern? BTW, I’m brewing ales. Should I try to chill the wort to a lower temperature first? I have been making yeast starters for my ales and have found very aggressive fermentations within 6 to 8 hours. Yesterday, I just rehydrated 2 packets of Safale-05 and found fermentation to be much slower. Bubbling only just started at 8 hours and slowly picking up the pace this morning. However, fermentation temp is in the low 60’s. I’ve never seen such a slow start (despite the advice of not doing yeast starters with dry yeast, I have done it several times and found lag times to be much shorter even with 1 packet of yeast used in the starter). So, will this slower start be an advantage if the temperature stays lower?
You’ll find that opinions are all over the board on this topic. Some people say fermentation temperature doesn’t seem to matter much at all, at least for most styles. Other people say it is absolutely critical to control temperature to the exact degree for the entire process. The truth is most likely someplace in between of course.
My personal belief is that almost all of the flavor components derived from the yeast come out in the first 2-3 days for ales, and after that the temperature doesn’t matter as much and it might even be best to increase temperature a lot to help the yeast finish the job and clean up after themselves before settling out for a long nap. With lagers, you don’t really want flavors from your yeast, so you need to keep the beer cold for at least the first 7-9 days, somewhere in there to minimize esters etc., and after that you can raise temperatures for the same reasons. A lot of people hold to about the same beliefs as mine.
Don’t be afraid to play around, experiment. It’s how we all learn. Don’t take anyone’s word for anything. We’re all wrong in some way. Do things your own way. Learn what makes good beer in your own process and environment.
:cheers:
I’ll also add that the particular strain of yeast selected is a huge factor in the amount of control needed, and the amount of time for which the control is needed.
+1. Very true.
[quote=“dmtaylo2”]
My personal belief is that almost all of the flavor components derived from the yeast come out in the first 2-3 days for ales, and after that the temperature doesn’t matter as much and it might even be best to increase temperature a lot to help the yeast finish the job and clean up after themselves before settling out for a long nap.
:cheers: [/quote]
I have to say Dave kind of caught me off guard with his response. The part I agree with is above.
I do believe it’s advisable to keep fermentation temperature to the lower levels of the yeasts range, typically low to mid 60s for the first 3-4 days. Then I let it ramp up to 69-70 for clean up and D rest.
I’m a believer in pitching at the low end of the yeasts range or below because those first few days are the critical days and I want my ales clean. They still have character from the yeast but fewer esters and usually no phenols.
Whether or not it is beneficial to the beer, to let the temperature rise late in the fermentation, may depend upon the yeast used.
