Fermentation vs. Carbonation

[jbambuti]

I follow the temperature guidelines for fermentation and bottle carbonation. I ferment my beers at the lower range of the yeast I'm using, and I bottle condition for at least 3 weeks around 70 degrees.

My question is, why do we ferment lower, but carb higher? Logic tells me that my yeast will always ferment in its optimum temperature range. Therefore, why should I have to raise the temperature to carb?

I'm cool with chemistry and technical reasoning, so no need to dumb it down. It works, but seems counterintuitive.

 

[menschmaschine]

Yeast will ferment below and above their optimal range, to a point. Many homebrewers bottle condition at higher temps simply to speed up carbonation. The little bit of fermentation that goes on during bottle conditioning typically doesn't produce enough esters, higher alcohols, etc. to be noticeable in the beer. Primary fermentation is the most important for temperature control because you're trying to capture a certain flavor profile from the yeast.

You certainly don't have to raise the temperature for bottle conditioning. However, in general, the lower the temp., the longer it will take to carb.

 

[david_42]

Just speed. Since the amount of sugars involved are small you don't have to worry about ester production.

 

[Revvy]

Just speed. Since the amount of sugars involved are small you don't have to worry about ester production.

Yep...Unless you are maybe carbing in 90-100 degree temps, but noone does that. Then I would wonder about ester production.

The 3 weeks at 70 degrees we mention is just a rule of thumb, and usually just for mid gravity beers. You can bottle carb a beer at any temp above your yeast's flocullation temp...but it will just take much longer.

I live in a loft with high ceilings, and in the winter I tend to keep the temps in the low to mid 60's because my heating bill is extremely high otherwise, and my beer takes forever to carb.....My 1.090 Belgian strong that I brewed in late winter took 3 months to carb, and really didn't take off till spring when the temps ramped up. That was a combination of the beer's gravity and the carb temp...

Most of the "regular" beers I made took iirc, 4-6 weeks to carb up during that time.

So you can do what you want in terms of carbing temps..BUT just don't expect them to be ready in 3 weeks...and don't start a "my beer is flat" thread about it either. Becasue we'll just tell you to be patient. Or warm the beer up a bit.

 

[malkore]

i'd also add that the yeast will be a little 'hesitant' at this stage since they've been without sugar for a couple weeks (or more), and most of the original yeast has settled out. 70F to carb is on the 'warm side of the safe temp range' just to give them a boost.

 

[Revvy]

i'd also add that the yeast will be a little 'hesitant' at this stage since they've been without sugar for a couple weeks (or more), and most of the original yeast has settled out. 70F to carb is on the 'warm side of the safe temp range' just to give them a boost.

Good point!