Temperature control

[FreshZ]

I Finally got an external thermometer. It's one of those stick ons from Midwest. I brewed a stout 2 nights ago and put it in my new fermenter pail with the thermometer. When I got home yesterday, I checked the temp and it said 77!! I ferment in my computer room and keep my house between 68 and 70. I immediately cleaned out a space in the unfinished part of my basement and put both of my fermenters down there on concrete. When I checked this morning, the temp was 72. A few questions.

1. Is that cheap thermometer reliable?
2. If house is at 68, basement is cooler (say 63-65), and the bucket is directly on concrete, what temp do you imagine the fermenter is actually at? Is the temp still dropping from being warm yesterday or is that my temp?
3. What else can I do to lower the temp? How does the used fridge option work? I know I don't want to ferment at 40*

 

[kapbrew13]

Search swamp cooler and fermentation chambers. Many examples.

The brew will be warmer then your room temp because the yeast are doing the nasty and creating heat.

 

[ludomonster]

You can put the bucket in a tub of water and add ice.

 

[Fennis]

I usually ferment in my basement which hangs around 58-63 depending on the time of year. I have an old basement which is mostly granite and crushed stone on the floor, so I put my bucket on a pallet to keep it off the ground.

The cheap thermometer is reliable enough, but I wouldn't say its going to give you the most accurate temperatures--more like a ballpark. Its hard to say what the temperature is inside. Its rather common to have the fermenting beer be warmer than the ambient temperature of the room as the yeast are doing their job. Once they settle down, the temperature will be pretty close to the ambient temperature in your basement. Ale yeast is very forgiving with temperatures, but 77 is way too high, so you did the right thing by moving it. If you are really concerned about keeping a lower temperature, you could get an old fridge and get a temperature controller, or do a search on this forum, there are lots of examples of DIY insulated boxes that people have made to control temperature.

In the meantime, you might want to find a way to get the fermenter off the concrete floor. The temperature of your concrete is going to be a lot cooler than the room temperature and that might cause an issue. Maybe I am way off base on that, but I don't know if I would set it directly on the concrete.

 

[FreshZ]

I usually ferment in my basement which hangs around 58-63 depending on the time of year. I have an old basement which is mostly granite and crushed stone on the floor, so I put my bucket on a pallet to keep it off the ground.

The cheap thermometer is reliable enough, but I wouldn't say its going to give you the most accurate temperatures--more like a ballpark. Its hard to say what the temperature is inside. Its rather common to have the fermenting beer be warmer than the ambient temperature of the room as the yeast are doing their job. Once they settle down, the temperature will be pretty close to the ambient temperature in your basement. Ale yeast is very forgiving with temperatures, but 77 is way too high, so you did the right thing by moving it. If you are really concerned about keeping a lower temperature, you could get an old fridge and get a temperature controller, or do a search on this forum, there are lots of examples of DIY insulated boxes that people have made to control temperature.

In the meantime, you might want to find a way to get the fermenter off the concrete floor. The temperature of your concrete is going to be a lot cooler than the room temperature and that might cause an issue. Maybe I am way off base on that, but I don't know if I would set it directly on the concrete.

That's fine and I can do this, but my temp is still at 72 with it being on the concrete about 12 hours.

I'm trying to research a swamp cooler that fits 2 buckets but isn't big money. Any suggestions?

 

[LiquidFlame]

Here's an example of a fermentation chamber that I built. https://www.homebrewtalk.com/f51/dual-fermentation-chamber-build-318098/

 

[FreshZ]

Here's an example of a fermentation chamber that I built. https://www.homebrewtalk.com/f51/dual-fermentation-chamber-build-318098/

That looks amazing but a little more money and space than I have right now. I guess I'm just gonna use the plastic bin and water/ice method.

Lid on or off the bin?
What temp should my cooling water be at?

 

[tom9d]

I live in an apartment where I don't have control of the heat, and it's always very warm. I don't yet have the money or space for a fermentation chamber, so right now I'm using a round rubber tub with some water in it and soda bottles with frozen water in them. Easier than having actual ice in there. Also have two tshirts soaked with cold water draped over the bucket, with a fan blowing on them. It's holding pretty steady between 64-66 degrees, down from 70 on its own.

 

[NordeastBrewer77]

I'm trying to research a swamp cooler that fits 2 buckets but isn't big money. Any suggestions?

The 'swamp cooler' being referred to here is simply a large bucket filled with water that you place the fermenter in. Costs around $7 at Home Cheapo. Something like this setup that I use. Really cheap and easy to get set up.

 

[Pie_Man]

I commonly have a 5-10 degree difference between the ambient air and the fermentation temperature. The temperature of the beer will get closer to the room's ambient temperature as fermentation subsides. Your basement seems to have a better ambient temperature than the computer room. You may want to start fermenting in the basement and then warm up in the computer room after 2-3 days, depending on your yeast strain of course.

As others mentioned, a swamp cooler is an effective way to maintain a desired temp. range. You can also you a fridge or freezer with a temperature controller for a more hands-off approach.

 

[zeg]

My stick-on strip thermometer seems to be quite accurate. I have that attached to my fermenter and the probe of a high quality digital thermometer taped to the side with the whole thing in a fridge. When it's been sitting long enough to be equilibrated, the strip always seems to agree with the digital thermometer.

The precision is another issue. My strip goes in 2-3°F steps. You can interpolate a bit because it seems that when the temperature is between steps, both of the bracketing segments "light up." So, e.g., if it's 65°F, the 64 and 66 will both be colored.

 

[FreshZ]

So I got myself set up with a couple swamp coolers. Now how do I monitor the temp of the fermentor? Isn't the stick on thermometer taking the temperature of the water/ice bath now?

 

[Pie_Man]

Using the fermometer assuming it's above the water level of the swamp cooler.

 

[jvp1]

You could use the stick-on, as long as it's above the water level, or you could use a floating beer and wine thermometer. The floater helps throughout the process, from steeping grains to chilling the wort, so I find it pretty indispensable.

 

[FreshZ]

Ok, what temp am I looking for in the water? My stick on us below the water line. I'm going to get another when I can and put it up higher on the pail.

Also, how long should it stay in the water? I read that the wort/beer needs to warm up slightly towards the end to allow the yeast to finish? Any idea on a timeline for when it comes out?

 

[RM-MN]

Your yeast is a biological agent that works slower at cooler temperatures and is exothermic. The cooler you get it (within the range that it works at all) the slower it works and the less heat it generates. As you let it warm up, it works faster and generates more heat which warms it up so it works faster and generates more heat. If you start it cool (like in your basement) it won't generate enough heat to offset the cooling of the air. Put it in a tub of water and it will be held even closer to the desired temperature. You only need to keep it cool while it is in the active phase, 2 to 4 days. I let mine set in the cool location for a week, then bring it where it is warmer so the yeast are encouraged to complete all the ferment activity.

 

[FreshZ]

Your yeast is a biological agent that works slower at cooler temperatures and is exothermic. The cooler you get it (within the range that it works at all) the slower it works and the less heat it generates. As you let it warm up, it works faster and generates more heat which warms it up so it works faster and generates more heat. If you start it cool (like in your basement) it won't generate enough heat to offset the cooling of the air. Put it in a tub of water and it will be held even closer to the desired temperature. You only need to keep it cool while it is in the active phase, 2 to 4 days. I let mine set in the cool location for a week, then bring it where it is warmer so the yeast are encouraged to complete all the ferment activity.

Gotcha. How much warmer? I can go to 68-70 in the basement or 70-76 upstairs?

 

[kmos]

Gotcha. How much warmer? I can go to 68-70 in the basement or 70-76 upstairs?

Depends on the yeast... Usually a couple degrees will be enough to invigorate them. If it is a strain that floccs out quickly, you may need to gently rouse them as well.

 

[oakbarn]

We have a room where we can control the temperature. We normally keep it about 65 for ales and 50 degrees for a lager. We use Stout Conicals that have a temp guage in them. We have calibrated all of our thermometers. We calibrated the fermenter ones at 65 degrees. We calibrate the MLT ones at 150 and the BK one at 170. All of them have a calibration screw on the back. Before we discovered calibration, some were off as much as 5 degrees. We do check the calibration occasionally but they are holding correct. We do have a calibration thermometer that we got from the LHBS.

We notice that there may be a 3 degree difference between ambient and fermenter for the first few days then they are the same.

 

[RM-MN]

Gotcha. How much warmer? I can go to 68-70 in the basement or 70-76 upstairs?

By the end of the first week your flavor profile is set and you don't really have to keep it cool from then on. I'd move it upstairs and let it complete the ferment at the 70 to 76.

 

[FreshZ]

By the end of the first week your flavor profile is set and you don't really have to keep it cool from then on. I'd move it upstairs and let it complete the ferment at the 70 to 76.

If my first couple brews were fermented too high, is that what is producing the chemically off taste?

 

[Jayhem]

If my first couple brews were fermented too high, is that what is producing the chemically off taste?

Fermenting too warm for the first week of fermentation is the biggest cause of off tastes. The swamp cooler route works but you can find a decent used fridge on Craigslist for $50 and a digital temp control is $60....best investment I have made yet for homebrewing!

 

[1KD1]

You could use the stick-on, as long as it's above the water level, or you could use a floating beer and wine thermometer. The floater helps throughout the process, from steeping grains to chilling the wort, so I find it pretty indispensable.

A warning about floaters:

Do not leave a floating thermometer in your mash tun during the "rest". Apparently they don't like that and explode. Luckily the inner glass tube (that holds the "mercury" red stuff) didn't break, just the outer glass that holds the little balls of Chinese lead (or steel?)

 

[FreshZ]

Fermenting too warm for the first week of fermentation is the biggest cause of off tastes. The swamp cooler route works but you can find a decent used fridge on Craigslist for $50 and a digital temp control is $60....best investment I have made yet for homebrewing!

Ok, assuming I go overboard with the cooling, what's the risk? Longer fermentation times or more off flavors? I think I can hit 60-66 but I'd like to know anyway.

Also, will the off flavors or esthers dissipate over time, or am I stuck with it. It's been in bottles almost a month.

The money for the fridge isn't as much an issue as space is. I have 3 fridges already in use plus a deep freeze.

 

[Jayhem]

Ok, assuming I go overboard with the cooling, what's the risk? Longer fermentation times or more off flavors? I think I can hit 60-66 but I'd like to know anyway.

Also, will the off flavors or esthers dissipate over time, or am I stuck with it. It's been in bottles almost a month.

The money for the fridge isn't as much an issue as space is. I have 3 fridges already in use plus a deep freeze.

You won't get off flavors from fermenting too cool, the worst that can happen is the yeast go to sleep until you warm them up a bit.

with 3 fridges can't you just borrow one of them for a week to use as a fermentation chamber and transfer it's contents to the other fridges for a few days? that's what I do.

 

[FreshZ]

You won't get off flavors from fermenting too cool, the worst that can happen is the yeast go to sleep until you warm them up a bit.

with 3 fridges can't you just borrow one of them for a week to use as a fermentation chamber and transfer it's contents to the other fridges for a few days? that's what I do.

Well one is pretty damn full of beer, the main one is for the family, the other one is a wine fridge and I'm not sure my fermentor will fit in there. I may try the wine fridge though, not a bad idea.

 

[FreshZ]

Ok, so I've got the Tub full if water and some ice. I have pulled my other fermentir out because it's been in 8 days. I just put another fermenter in there 2 nights ago. When I pulled the other fermentor out, the thermometer seems to be broken from the water. I've got 2 new ones to stick on but it seems like catch 22. If I put it lower on the ale pail, it gets wet and ruined, if I put it higher, it won't be touching the beer. Where do you put it?

I would really like to know my internal temp. I'm just guessing right now and reading the cooling water. Any solutions?

 

[FreshZ]

So is this question just too stupid to answer? Is my water level just too high in the swamp cooler? I have it up to the level of the beer in the pail.

 

[1KD1]

I would try another thermometer and lowering the water level. I don't use a swamp cooler but have read many threads about people using wet t-shirts and a fan along with the swamp cooler, so I am guessing their water level isn't that high.

 

[Jayhem]

Ok, so I've got the Tub full if water and some ice. I have pulled my other fermentir out because it's been in 8 days. I just put another fermenter in there 2 nights ago. When I pulled the other fermentor out, the thermometer seems to be broken from the water. I've got 2 new ones to stick on but it seems like catch 22. If I put it lower on the ale pail, it gets wet and ruined, if I put it higher, it won't be touching the beer. Where do you put it?

I would really like to know my internal temp. I'm just guessing right now and reading the cooling water. Any solutions?

Because water transfers heat much faster than air you can be sure that the beer temp is no more than 2 degrees warmer than the water in your swamp cooler even at high krausen fermentation stage.