Fermenting temperature -- how important?

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

billpaustin

Supporting Member
HBT Supporter
Joined
Mar 6, 2013
Messages
286
Reaction score
11
I just started, my first batch is great!

I live in the SW mountains, and I normally don't run the heat at night. I heat the house up to 68 during the day, but it can drop to 58 at night (typically 60). If I build a good fire, it could rise to 72 for the whole night. Is this variation a problem?

How important is a constant temperature to fermenting?
 
Too much variation will stall your fermentation. So yes, it is important.

Also, going to warm will cause flavor changes and sometimes produce fusel alcohols, which produce pounding headaches.
 
Thanks for the replies, this will complicate things for me.

In the summer, we can get up to 80, or even 85 for a short time in the day, while dropping back to the 50's-60's at night. The air is very dry here (8% is common), and at 8,000 feet, there are few bacteria. I do not have air conditioning, but sometimes run a simple humidifier (wet pad with a fan). So in the summer I'll have to ferment in a fridge.

In the winter, I could run central heat and keep the house at 68, but I normally turn it off at night; the house temp can drop to below 60 if it gets cold outside. So I'll need a heating system, since a fridge can't warm it above room temp, can it?

edit: also, this is air temp. I have a 5 gal-carboy inside a box, so the beer temp will not fluctuate nearly as much. I'll need to get a thermometer to attach to the side.
 
A tub of water will help even out the temperature changes. Set the fermenter right in it and insulate around it. An aquarium heater can keep the water temperature pretty even but you need to find one that controls it at 60 to 64 F. Warmer will not make as good of beer.
 
So I'll need a heating system, since a fridge can't warm it above room temp, can it?

You can use a fridge for both with a few extra pieces of equipment. You'll need an external temperature controller that will allow you to control both heat and cooling. You can plug your refrigerator into the cooling half of the controller when you need cooling. You can also install a heater of some kind into the refrigerator to keep your fermentation warm, too. In this case, the controller keeps the refrigerator off, and the heater on. The refrigerator then acts like a big insulated box, keeping the heat in. It's not too difficult of a project. Do some searches here on temperature control and you'll see some other brewer's projects. Those will give you some ideas you can use.
 
Warmer will not make as good of beer.

Not always true. I've used plenty of yeasts that like the 65 - 68 range and I've brewed both belgian dubbels and saisons that want to be up to 80 for the right flavor profile. I built a box out of 2" building foam and used a reptile ceramic heater to push the fermentation to 80 for my saison. Tasted great and is right for the style.
 
Well your temps aren't crazy-out-of-range so it might as simple as putting your carboy/bucket in a box (hell it could be made out of cardboard, but preferably an insulate plywood or old fridge sorta deal) with a spaceheater hooked to a thermostat. At night it would (if necessary) warm your fermentation space back up to the mid 60s or wherever you wanted.
 
+1 on the swamp cooler. I got a big plastic tub with rope handles from wal mart for 5 bucks and a $20 aquarium heater. Perfect for winter and in the summer dropping in some frozen water bottles keeps it cool. The water bath really helps keep the wort temp stable even if the air fluctuates.
 
With a 58-68*F temp range, if you can figure out a way to insulate the fermenter from the outside air, that will help you a bunch. For the first 5-7 days, the batch will be generating a bit of its own heat, so you can make use of that some.

If you're doing a typical ale, keeping it in the mid-60's and as steady as possible will serve you well.
 
I think there are some great ideas here and just want to reiterate that proper fermentation temps is at the very least one of the top 3 most important aspects of making good beer.

Also, and maybe however, if you can pitch your yeast at the low end of its temp guidelines you may be fairly well set- the fermenting beer will create a lot of its own heat and will warm itself during fermentation unless there is a large temp differential with the outside air.

Hey at least you don't live in Miami!
 

Latest posts

Back
Top