More beginner fermenting temperature questions

Which is better - a consistent but slightly high fermenting temperature, or a lower average temperature which fluctuates?

I live in a small apartment (just over 700 sq. ft) so even finding space to leave the fermenter is a little tough. I have the bucket sitting in a water bath which I add frozen water bottles to once or twice a day. If I don't, the water bath temperature averages about 72-74 degrees. If I use the ice method, the temperature tends to fluctuate between 64 -72 degrees. Does temperature fluctuation raise any problems? If so, are these problems worse than a high fermentation temperature?

Secondly - is it important to control the temperature of the secondary vessel? I know fermentation should be complete, so I'm guessing its alright to let it warm up a bit. I have a beer in my secondary and I'd like to use the primary for another batch, but space constaints only make it feasible to have one vessel in a water bath.

Thanks again for helping another newbie brewer.

Higher temps have always left me with off flavors. Colder and more consistent the better for primary and secondary.

I run into the same problem you have. I pay the most attention to temperature during the first 4 days of fermentation, after that I do what I can but don't go way out of my way to keep them cool. You should try to avoid wide temperature fluctuations, but keep in mind that 5 gallons of liquid won't fluctuate near as quickly or as much as air temperature can.

Do the best you can, use yeasts that are tolerant of the fermentation temps that you're able to provide and you'll be able to make fine beer.

I hate to say it but I believe temp really depends on the yeast. I know it's not an answer to fluctuation but I'm on a yeast knowledge kick at the moment and some yeast really like 70-75 and some like 65-68.

For instance WLP001 California Ale Yeast has no probl;ems with warmer ferments and some people go for 75. But WLP001 California Ale Yeast likes 65-68 for the best results.

A lot of times it's not "off" flavors but just different flavors. More esters at higher temps and so forth.

Yet another thing to keep notes on. Just stay in a range and do what you can.

I'm inclined to go the route of a lower average temperature with some fluctuation. Lower temps may make the yeast a little sluggish, so fermentation may take a bit longer- but it will be a cleaner ferment. You should remember as well that fermentation is an exothermic process and the temperature of the wort may well be 5-10 degrees higher than ambient.

The first several days of fermentation are the most crucial temperature-wise, so keep the carboy as cool as possible. I try to get mine around 60 to keep the fermentation temperatures within the ideal range and minimize any fruitiness that can come from higher temps.

Good luck!

Thanks all.

flyangler18 said:

I'm inclined to go the route of a lower average temperature with some fluctuation. Lower temps may make the yeast a little sluggish, so fermentation may take a bit longer- but it will be a cleaner ferment. You should remember as well that fermentation is an exothermic process and the temperature of the wort may well be 5-10 degrees higher than ambient.

The first several days of fermentation are the most crucial temperature-wise, so keep the carboy as cool as possible. I try to get mine around 60 to keep the fermentation temperatures within the ideal range and minimize any fruitiness that can come from higher temps.

Good luck!

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Thats a good point. Just to verify, when a recipe or post here refers to fermentation at a certain temperature and doesn't specify, are they referring to the ambient temperature or the temperature of the actual wort?

You could also build one of these and put it in your closet. http://home.elp.rr.com/brewbeer/chiller/chiller.PDF

I've been responding with this to most questions on the temp issue. It's small enough for an apartment... just would need to have enough room in a freezer to freeze some gallon sized containers.

Fermentation temps refer to the temperature of the wort - the medium suspending the yeast. You can use a thermowell to drop a probe into the wort or just tape a sensor to the side of the vessel and you'll get kinda close enough. If you're using your wall thermostat, remember the initial stages of fermentation create a bunch of heat and you can have 5-6 deg elevation in the wort just due to fermentation.

That said - I like to see consistent temps and avoid any more than at 4-5 deg swing in a day, if possible. But 72-74 can be pretty hot for most yeast and with the added heat from fermentation you could be 80 or over. I'd keep it as cool as possible for the first 48 hours and then try and keep it consistent. At warmer temps you'll get lots of esters, but if your temp fluctuates wildly you may get weird esters.

Gordie

Gordie said:

Fermentation temps refer to the temperature of the wort - the medium suspending the yeast. You can use a thermowell to drop a probe into the wort or just tape a sensor to the side of the vessel and you'll get kinda close enough. If you're using your wall thermostat, remember the initial stages of fermentation create a bunch of heat and you can have 5-6 deg elevation in the wort just due to fermentation.

That said - I like to see consistent temps and avoid any more than at 4-5 deg swing in a day, if possible. But 72-74 can be pretty hot for most yeast and with the added heat from fermentation you could be 80 or over. I'd keep it as cool as possible for the first 48 hours and then try and keep it consistent. At warmer temps you'll get lots of esters, but if your temp fluctuates wildly you may get weird esters.

Gordie

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I've been taking the temperature of the water around the bucket and not the room ambient temperature. I'm guessing this gives a better reading than the ambient temperature in the room.

I tasted a sample when going from primary to secondary and didn't really taste any fruitiness or any of the flavors I've heard are caused by warm fermentation. It actually tasted pretty good.

If this batch does wind up turning out I think I'm just going to maintain the water bath and ice method. With summer ending it should make it quite a bit easier to control the temperature.