Fermentation Temp.

[violinguy]

Assuming I'm within the range of the given yeast, what are the advantages to fermenting at the low-end or high-end of that range? I know that for bottle conditioning and carbonating, the higher end is better, but what of fermenting?

Are there flavors that come through better if I ferment at 70 vs. 65? At this point in the year, I am able to ferment cooler if necessary, or at temps up to 70-72.

Thanks!

 

[Ashevillain]

The flavors will be different. Say on each extreme, too low and your yeast might not be able to even start, too high and its going to produce esters and harsh alcohol byproducts you dont want. Say low end of acceptable range is 62, this will give you a very clean flavor with minimal esters, you may way to ramp up temps a little at the very end to help it completely clean up. High end being 68-70 your going to get a higher ester profile, resulting in more fruitiness or spiciness depending on the yeast strain, you shouldn't get esters to the point of off flavors in that range. Again sometimes it helps to go higher in the end even if your going for the clean profile. Look up your strains ranges, i stuck to the lower end till i was comfortable and wanted to experiment.

 

[PADave]

Totally depends on the yeast. For example, US05 can give off peachy off flavors if too low. On the other hand, I believe Nottingham can give off flavors if too high.

 

[microbusbrewery]

Generally speaking, the lower you are in the range, the cleaner the fermentation profile will be meaning less yeast character. The higher you are in the range, the greater the flavor contribution from the yeast. In most cases, you can start a few degrees lower than the stated range, but you have to consider the yeast strain and style you're brewing. For example, if you're want a super clean almost lager-like profile in your pale ale, keep it on the cool side especially the first few days. On the other hand, if you're brewing a style like a Saison that's supposed to have a fair amount of flavor contribution from the yeast, you don't want it to be too cold. On that same note, you don't want a Saison to be overpowering on the yeast character either. I judged some Belgian categories a couple years ago at a local homebrew comp and too many of them were so over the top on esters and phenolics that they turned me off many Belgian styles for over a year.

For me, I almost always start off a few degrees lower than the lowest recommended temp, then ramp up the temps over a week's time, usually hitting the middle to upper end of the range by the end of the first week.

 

[violinguy]

Cool. Thanks for the info!

 

[eric19312]

Also be aware temperature of your fermenting beer may be different from temperature of the room it is fermenting in. Fermentation creates heat and during peak activity (maybe at high krausen) the beer can reach several degrees higher (some claim up to 10 degrees) than the room. This is why it can be a good idea to start the beer in a location where the ambient temperature is at the low end of the yeast's range. As fermenation takes off the yeast will warm the beer up to the middle of the range, maybe higher. Then as fermentation slows down good idea to move the fermenter to warmer room to finish. Anything from the middle of the range to the high end of the yeast's range is good here.

The reason to move the beer to a warmer place is to make sure the beer doesn't start to cool back to the low end of the range. This is thought to put the yeast at risk of going to sleep too soon. Some people (ok me) worry about even a small downward change in temperature.

I go with active dual stage temoerature control. Lots of threads and articles in here about converting a fridge or chest freezer to do this. I start US05 at 66-68 and then increase to about 70 as fermentation slows. Belgians I will start in middle of range, then after about 3 days start increasing temperature by 1 degree F each day for 10 degrees or so.

 

[violinguy]

Also be aware temperature of your fermenting beer may be different from temperature of the room it is fermenting in. Fermentation creates heat and during peak activity (maybe at high krausen) the beer can reach several degrees higher (some claim up to 10 degrees) than the room. This is why it can be a good idea to start the beer in a location where the ambient temperature is at the low end of the yeast's range. As fermenation takes off the yeast will warm the beer up to the middle of the range, maybe higher. Then as fermentation slows down good idea to move the fermenter to warmer room to finish. Anything from the middle of the range to the high end of the yeast's range is good here.

I go with active dual stage temoerature control. Lots of threads and articles in here about converting a fridge or chest freezer to do this.

Awesome. Thanks. This will a first for many things - 1st batch over 1 gallon (3 gal), 1st with new fermenter, and 1st with temp gauge on the fermenter so I can have better temp. control.

Also, 1st with coffee grains (steeping), and probably the last batch to use extract. Fingers crossed.

 

[petrolSpice]

Lower temp is cleaner, less flavors from the yeast. High temps yield more flavors from yeast and can help result in higher attenuation (lower FG). Some beer styles you want to ferment high because much of the flavor comes from the yeast, such as saisons and even hefeweizens.

It's generally okay to ferment below the range for ales. For example, WLP001 calls for 68-73F and I will usually ferment it around 65F.

64-68F is generally a safe range for ales.

At the very least use one of those sticky fermentation temperature gauge things because it will always ferment warmer than the room temp.

If you're curious and ambitious, you could split a batch into two fermenters and ferment one at 65F and the other at 75F. The difference in taste should be apparent.