FYI on Fermentation Temperature

I am a long time brewer just getting into wine making. While I understand from brewing that fermentation is a exothermic process producing heat it seems that even more heat is produced during active wine fermentation. My beer wort will sometimes get 5-6F above ambient temperatures but I have seen my wines at 10F higher than ambient. Just something to keep in mind that the room temp may not be a very good indicator at all as far as must temp is concerned during those first few days. Still not sure how critical it is for wine but for beer 10F is a huge difference!

Temp is important and I agree, room temp is no indicator. Get a floating thermometer and watch-and record those temperatures. Besides helping a happy fermentation, it is nice to know what to repeat when things go well, and more important, what not to do when they go wrong.

I ferment beer in a chest freezer with a digital thermostat sitting inside a dip tube that takes the temp at the center of the beer. I set it and forget it knowing that my fermentation temp will not vary by more that 1F. The problem is that this is for a carboy aerated with pure 02 sitting inside a closed freezer whereas for wine I have a bucket that needs to be exposed to air so I was trying to look for an ideal place.

Having discovered this I may need to rethink about how I can ferment wine in there without starving it of O2. Life would be so much easier if I could just treat the wine with O2 and add an airlock.

We've been cooling our fermentations the last few years and it has made a HUGE difference. We live in S. Florida and realized we were blowing off all kinds of esters and volatile compounds, as well as probably stressing the yeast a little. Now we control the temp by having our fermenter in a big plastic tub filled with water, and we put frozen water bottles in periodically. We keep our whites in mid 60's low 70's and reds below 80. Our wines have improved tremendously.

jsbeckton said:

I ferment beer in a chest freezer with a digital thermostat sitting inside a dip tube that takes the temp at the center of the beer. I set it and forget it knowing that my fermentation temp will not vary by more that 1F. The problem is that this is for a carboy aerated with pure 02 sitting inside a closed freezer whereas for wine I have a bucket that needs to be exposed to air so I was trying to look for an ideal place.

Having discovered this I may need to rethink about how I can ferment wine in there without starving it of O2. Life would be so much easier if I could just treat the wine with O2 and add an airlock.

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Ditto for beer. I plan to use the same method with my next wine. Just open the chest and give it a stir once a day....it's not going to effect the temps that much. If you have O2, stir and give it a snort! I figure keeping the wine yeast in the happy zone can only be a good thing.

Still new to this temp controlling...first beer is now cold crashing at 36 degrees....love it, punch a few buttons and went from 63 to 36 and holding steady.

A few months ago when I was looking for advise on my first batch I was basically told that you can't just treat wine with O2 at the beginning and add the airlock like you do with beer. I really am not sure I believe that but am afraid to try it since everyone seemed to be so against it. I guess now that I have been leaning towards only making wines with skins maybe the 1-2x stirs a day make it ok to close the chest freezer. Anyone else do it this way?

I would think the chest freezer would limit oxygen too much.

What most folks who cool the fermentation do is get a large tub, fill it with water/ice, and leave the lid off the primary fermenter. They put a cloth over the top, so the fermenter is open to the air.

I don't cool my fermentations because they are within the yeast's tolerance range. I put the lid to my fermenter on loosely at the beginning.

I just put a cloth over the chest freezer rather than close the lid. This is just a game you don't have to play with beer as you limit air as soon as fermentation begins.

Noontime said:

We've been cooling our fermentations the last few years and it has made a HUGE difference. We live in S. Florida and realized we were blowing off all kinds of esters and volatile compounds, as well as probably stressing the yeast a little. Now we control the temp by having our fermenter in a big plastic tub filled with water, and we put frozen water bottles in periodically. We keep our whites in mid 60's low 70's and reds below 80. Our wines have improved tremendously.

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David,

I live in South Florida also, but hadn't thought about using a large water tub to cool the wine. How often do you replace the frozen water bottles; and, do you use the tub only for the primary fermenter or do keep the chill bath going through out the wine making process?

Thanks for the tip.

So you are cooling the must down, this will mean the yeast are going to consume O2 slower, every time you open the chest up you are stirring up the air adding some new in and pushing some old air out, I think you will be fine - depending, are you making a white or red wine? Why would you be able to give your carboy a shot of O2 and stick on an airlock if you have some surface area during the vigorous stages? I think you are making this to hard on your brain, you already know how to grow beer yeasts are wine yeasts some other kind of creature?

So soon I should have the oppurtunity to get one of these chest freezers and a digital gizmo to keep it cold and maybe some kind of probe thing to that goes in the musst to see how hot its getting, using it for cider, so once it gets going no more O2 and run a long cool ferment. What kinds of controllers are you guys using? WVMJ

WVM, beer wort is boiled so it has less O2 to start. Not sure what else about the process or the yeast prohibit me from aerating with pure O2 so the yeast have all that they need. Trust me, this is great as I can walk away for a month and know it will ferment perfectly. With the wine I will just have to let the chest freezer work harder to maintain temp as I can't seal it.


I use a Ranko digital controller that is pre wired. Just plug my freezer into the controller, plug the controller into the wall and set the desired temp. Done.

Also, if I need to warm it up I just put a small shop light in the freezer and toggle the controller to hear mode and let the small bulb heat the freezer (with carboy wrapped in towel to block light).

You can let the probe just hang in the freezer but like i have been saying, best is actual fluid temp so I use a dip tube that is attached to the stopper. They sell them pre made but I just drilled a solid stopper and added a metal tube with one end sealed with silicone. Perfect seal and perfect temp readings!

I also live in south Florida. But I Ferment in my wine room which is 66-67* year round. I first thought it would slow my ferments too much, but realized quickly how much better that temp is. Roy

I have found that simply placing a fan blowing on the primary can bring the temps down fast! I was amazed how high the must temps were getting in the first few days of ferment so I moved my operation into the basement (wifey was happy about that ), and record SG and temp twice daily. If the temp gets too high I set a 20" fan about 3' from the primary and within 12 hours the must temp will come down as much as 8*. I live in northern MN however and our temps rarely get much above 90 up here. The basement stays around 70-75 in summer. You brewers in FL have a bit more of a challenge.

WVMountaineerJack said:

So you are cooling the must down, this will mean the yeast are going to consume O2 slower, every time you open the chest up you are stirring up the air adding some new in and pushing some old air out, I think you will be fine - depending, are you making a white or red wine? Why would you be able to give your carboy a shot of O2 and stick on an airlock if you have some surface area during the vigorous stages? I think you are making this to hard on your brain, you already know how to grow beer yeasts are wine yeasts some other kind of creature?

So soon I should have the oppurtunity to get one of these chest freezers and a digital gizmo to keep it cold and maybe some kind of probe thing to that goes in the musst to see how hot its getting, using it for cider, so once it gets going no more O2 and run a long cool ferment. What kinds of controllers are you guys using? WVMJ

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Jack...I use the InkBird 308...kinda of the mid priced range...not difficult to use and I hate punching buttons. It has both a Cooling and a Heating setting....so come South Texas winter, I can use a small heater in the freezer and control the temp swings within 2 degrees. Being too cool is not a problem right now.

https://www.amazon.com/s/ref=nb_sb_ss_i_1_7?url=search-alias%3Dindustrial&field-keywords=inkbird&sprefix=inkBird%2Cindustrial%2C495

In my limited use thus far, it has worked great. I fermented a SMASH beer at 63 degrees for 3 weeks and then simply turned the temp down to 36 for a cold crash to really settle the yeast and trub. BTW, the freezer turns on very seldom and only has to run a short period of time.....and it is out in my 100 degree shop!

Now that have one, I wonder why all freezer aren't set up this way? It just gives you so many more operating uses....freezer, fridge, beer cooler, produce cooler...just set the temp where you need it.

Mismost said:

Jack...I use the InkBird 308...kinda of the mid priced range...not difficult to use and I hate punching buttons. It has both a Cooling and a Heating setting....so come South Texas winter, I can use a small heater in the freezer and control the temp swings within 2 degrees. Being too cool is not a problem right now.



https://www.amazon.com/s/ref=nb_sb_...ywords=inkbird&sprefix=inkBird,industrial,495



In my limited use thus far, it has worked great. I fermented a SMASH beer at 63 degrees for 3 weeks and then simply turned the temp down to 36 for a cold crash to really settle the yeast and trub. BTW, the freezer turns on very seldom and only has to run a short period of time.....and it is out in my 100 degree shop!



Now that have one, I wonder why all freezer aren't set up this way? It just gives you so many more operating uses....freezer, fridge, beer cooler, produce cooler...just set the temp where you need it.

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I couldn't get that link to open for some reason but it sounds like an analog controller. I have 2 freezers, one is the serving freezer holding my kegs at a steady 42F and I never adjust it. The other is on the digital thermostat that I use for my fermentation a and I adjust it constantly up/down or heat/cool.

I think that the analog is great for a serving cooler because you set it and forget it. For the fermentation cooler I like the digital for a few reasons. For one, the probe fits in a dip tube where my analog one would be way too big. This is a must for me because I think a dip tube is absolutely necessary as the cooler temp may be way different than wort/must temp. Secondly I can see two temps actual/desired and third I can adjust it from heat mode to cool mode with the touch of a button. There may be workarounds for analog controllers but this is just my opinion after having both for several years. YMMV.

jsbeckton said:

I couldn't get that link to open for some reason but it sounds like an analog controller. I have 2 freezers, one is the serving freezer holding my kegs at a steady 42F and I never adjust it. The other is on the digital thermostat that I use for my fermentation a and I adjust it constantly up/down or heat/cool.

I think that the analog is great for a serving cooler because you set it and forget it. For the fermentation cooler I like the digital for a few reasons. For one, the probe fits in a dip tube where my analog one would be way too big. This is a must for me because I think a dip tube is absolutely necessary as the cooler temp may be way different than wort/must temp. Secondly I can see two temps actual/desired and third I can adjust it from heat mode to cool mode with the touch of a button. There may be workarounds for analog controllers but this is just my opinion after having both for several years. YMMV.

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The InkBird is digital JSB..."I hate punching buttons" comment threw you off...I just meant it was easy to program by punching buttons! I agree with all your reasons for using a digital controller and it was 40-50 bucks cheaper than an old Johnson analog...AND it can do heating and cooling with it's dual power outputs.