Clarification on Fermentation Temps

Hey Beer People--

My ferments are coming in a little high, have had no issues w/ bottle bombs but would like the beers a bit drier. The stick-on thermometer on my plastic bucket fermenter tends to read around 60-62F, but fluctuates due to changes in ambient temp from the climate. I So I am very pleased to have picked up a used adjustable aquarium heater that will keep water in my basement utility sink at 68-70F, which I was planning to use as a water bath to try to get stronger ferments (I am also trying some other things like switching to DME that I expect will ferment dry, and adding my extract late in the boil to combat caramelization of the beer in a partial boil, mashing is not an option).

Here are my two questions (I am basically trying to figure out what temp to set my water bath at):

-How warm should I ferment my ales if I am hoping to get complete fermentations?

-When people or books say "I fermented at 62-64F" or whatever temp, are they talking about the temp of the room (for me, the water bath) or the internal temp of the fermentation? I will do some experimenting and adjust my thermostat to hit whichever target, but I need to know what to aim at.

Thanks!

Different yeast strains work at different temperatures. Fermentations at the high end of the spectrum can lead to off or unwanted flavors. Fermentations towards the low end can sometimes stall out prematurely. I usually try to shoot somewhere in the middle of the reccomended temperature range of any given yeast. When measuring temperatures, you are looking to measure the temperature of the liquid inside the vessel, not the ambient air temperature. In a waterbath situation such as yours, measuring the water should be quite accurate. Remember, that active fermentation can increase the temperature of your beer considerably, so adjust accordingly.

The exact fermentation temp will depend on what style of beer you are brewing, type of yeast you using and if you are looking for more or less esters from your yeast. From the information I have gathered over the last few years 68 F appears to be a good middle of the road temp.

Jamil Z and John Palmer have a new podcast Brew Strong and they did an episode on attenuation. It would be a good episode to listen to in this situation.

It sound to me like your fluctuating temps are causing your yeast to floculate early and not finish up.

Unless I'm doing a Belgian, I like to ferment at the lower end of the range, usually 60-62 degrees (wort temperature, not ambient temperature). It makes cleaner tasting beer with less fruitiness, and bring out the hops better.

It really does depend on your yeast, so let that be your guide. Of course, if you're using liquid yeast, make sure you use a starter to pitch enough yeast. For dry yeast, a yeast like Nottingham or s-05 are pretty high attenuating yeast (and nottingham works done to 57 degrees) and will give a nice clean ferment.

+1 for the aquarium heater.
I've found that the temp inside the fermenter can be serveral degrees higher than room temp.
But with a water bath, the temp inside is within a degree of the bath temp.

BTW, other brewers have reported that the stick on thermometers are not waterproof.

+1 on Yoopers comments. I too will shoot for the 62* mark when using S05 and Notty, as they attenuate so well. Right now I've got BM's Octoberfast fermenting with S05 at 59* to insure minimal ester production.

I need some help on this one too. I keep my house at 80 or so. I have started to use a water bath and ice to control the temps. I am keeping the temps lower now but I have a 5-7 degree fluctuation from the time I leave in the morning to the time I get home. Will this fluctuation have any affect on the fermentation? My temps are still staying within the yeast range.

The more you can steady the temp the better. Get some foam insulation from a home supply. The thicker the better and build a box. Just use tape to hold it together for a temporary box. Cut a door and make a tape hinge for it to add ice to the bath. This works really good if sealed up well.

egolla said:

+1 for the aquarium heater.
I've found that the temp inside the fermenter can be serveral degrees higher than room temp.
But with a water bath, the temp inside is within a degree of the bath temp.

BTW, other brewers have reported that the stick on thermometers are not waterproof.

Click to expand...

Have used the water bath method for quite some time and had no problem with my stick thermometer. I was worried about it because I read this somewhere too, but hasn't happened to me yet.

Sounds good. So I will need to get my water bath dialed in ahead of time for the planned temp and then just put the bucket in there after the yeast is pitched. I use a floating thermometer from the LHBS to measure the temp of the water bath (I just leave it in there unless I am brewing with it).

So for example if I am fermenting w/ US-05 (advertised 59F to 75F) and I want a cleaner tasting beer, I want my ferment to occur at around 65 so I set my water bath at 65? The only question is should I try to compensate for the warming effect of active fermentation by setting my water bath lower (like around 60) for the first and then turning up the heat to try to hold the 65 as fermentation slows? I think the yeast is really pooping out below about 63 but maybe it's my recipe or process that are causing my sweet flavors...

Thanks guys!

So for example if I am fermenting w/ US-05 (advertised 59F to 75F) and I want a cleaner tasting beer, I want my ferment to occur at around 65 so I set my water bath at 65? The only question is should I try to compensate for the warming effect of active fermentation by setting my water bath lower (like around 60) for the first and then turning up the heat to try to hold the 65 as fermentation slows? I think the yeast is really pooping out below about 63 but maybe it's my recipe or process that are causing my sweet flavors...

Click to expand...

That's right and so that is why I always write about using a refrigerator and a temperature controller. It takes care of this problem. Sometimes people just give away a refrigerator for free.

ScoutMan said:

+1 on Yoopers comments. I too will shoot for the 62* mark when using S05 and Notty, as they attenuate so well. Right now I've got BM's Octoberfast fermenting with S05 at 59* to insure minimal ester production.

Click to expand...

+2. Notty and US-05 work GREAT at 62*F. If you pitch 2 pkgs you will get a beer that is lager clean. S-04 I ferment at 64*F, and Belgians I pitch at 66*F and slowly ramp up into the mid 70's.

If you aren't getting the attenuation you want follow the recommendations of the Mr Malty pitching calculator; you may not be using enough yeast for the job, so they are going on strike.

What are the chances that my issue is oxygenation of the wort?

I try to do a lot of sloshing in the bucket, mix extremely vigorously w/ a sanitized stainless spoon so it foams up, pour from up high through my strainer, etc, but don't use an oxygenation stone or anything. When I put a new wort on an old yeast cake I do my oxygenation in my bottling bucket then put it on the yeast cake and swirl it around a bunch and then close it up. That should be doing the trick... right?