How do YOU measure ferment temp?

Some of us use bathtubs; others coolers, closets, or kegerators to maintain temp. These are all great methods, but HOW DO YOU MEASURE THE FERMENTATION TEMP?
A simple Fermometer on the side of a carboy?
A thermowell?
Temp probe taped to the side?

Or....something else?

I wonder, because I want to KNOW that I'm fermenting at the temp I THINK I am...

CHEERS

Fermometer stickers on carboys... for the square plastic containers i got for lagering, the fridge or setting it beside an already filled carboy and using that temp.

SWAG...
Scientific Wild A$$ Guess
JJ

I jam a thermometer or RTD in the longer rubber nipple of the carboy caps.

Fermometer stickers on carboys

mr x said:

I jam a thermometer or RTD in the longer rubber nipple of the carboy caps.

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RTD? What's that? Do you leave said thermometer in, or just take temps periodically?

An RTD is a resistance temperature detector. The ones I use are 100 ohm platinum, encased in 1/4 SS tubing. They connect to a controller (Watlow, Omega, etc.). If I want I can control the ferment temp to +/- .1 degrees f.

Sometimes, I just use a glass thermometer. I leave them in, no need to take it out.

The temperature probe off the thermostat, dangling into the chest freezer that serves as my fermentation chamber. I don't measure the beer temperature directly, although I've thought about it. I figure the fermenting beer is a little higher than what my thermometer reads. Over time, I've figured out what works.


TL

Fermometer, no doubt. Doesn't get any easier---or cheaper.

When I use the water in the cooler method, I float a thermometer in the water. The water would be roughly the same temperature as the beer inside the carboy. I use a fermometer strip on the carboy if I'm not using the water bath. (Water ruins the fermometer strip).

What is the general consensus on the difference between the temp measured in a water bath and the actual temp in the fermenter during active fermentation? 2, 3, 4 degrees?

I tape the temperature probe from a min/max thermometer to the side about half way up the fermenter. I used to put a piece of sponge over the probe to insulate it from the environment, but determined it didn't matter.

Don't know about water baths, but last year several people (including me) ran tests comparing the wort temperature and the outside of the fermenter and found no difference within the accuracy of the thermometers. The amount of heat generated by a 5 gallon batch is small relative to the thermal conductivity of a bucket or carboy.

david_42 said:

I tape the temperature probe from a min/max thermometer to the side about half way up the fermenter. I used to put a piece of sponge over the probe to insulate it from the environment, but determined it didn't matter.

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I did the same thing and had the same results. A thermometer probe taped to the carbuoy exactly matched the reading on the fermometer. For a non-fermenting beer, air temp should be beer temp after 12-24 hours.

have analog temp controller (with a bulb) that I bought at my LHBS, but I'll probably use it for the kegerator and make a DIY remote probe thermostat controller for the fermentation temp controller. That way I can set it to the desired brew temp and not worry about the diff between air temp and brew temp.

I've got an analog temp controller that I just dangle in my brew fridge...

I should get some fermometors...next AHB order i will

i use an in/out thermometer in my fermentation chiller and tape it directly to the carboy. i find it shows the same temperature as the fermometer on the carboy.

i would like to actually set this up so the carboy temp links directly to the thermostat. that way it would turn the fan on based on the wort temperature and not the air temp...i find i always have to set it a bit lower than what i want. that's a project for when i find a bigger place and build a wooden fermentation chiller

anyone ever used a floating thermometer inside the carboy? i've been thinking of picking one up to try it out...

I use the fermometers as well. They're easy to read, cheap and don't take up any room.

I have a temperature controller taped to the side of my bucket. I also have a 'refrigerator thermometer' that sits on top of the bucket. The thermometer on top is always a couple degrees higher. This is the warmest area in the fridge so I use that to make sure its at least 5 degrees below the upper range of my yeast.

Howdy:

Here is my .02.

I've got a Ranco probe inside a SS tube (welded shut) through a bung in the top of the carboy. The Ranco then controls the converted freezer.

Dan

YooperBrew said:

When I use the water in the cooler method, I float a thermometer in the water. The water would be roughly the same temperature as the beer inside the carboy. I use a fermometer strip on the carboy if I'm not using the water bath. (Water ruins the fermometer strip).

Click to expand...

I was thinking about covering my fermometer strips with clear waterproof tape. I'm not 100% sure if it will work or not to keep them dry but it seems like it should.

Wow, sure are a lot of old threads being brought back to life today.

About +10 for Fermometers, although I think that they're more accurate in reading the ambient temperature than they are the temperature of the beer itself.

I use a thermowell with a Ranco probe.

I measure the ambient temp in my igloo cooler with a standard glass thermometer taped to the top slope of the Better Bottle. I keep temps near the lower end of the yeast's temperature tolerance to prevent premature flocculation (i.e. I won't under-cool the ambient to correct for the higher temps within the Better Bottle). For most ales, I stick to the 65-68 degree range, moving up into the 70s after active fermentation has stopped to encourage the yeast to clean up after itself.

with this dohickey

hagbardceline said:

anyone ever used a floating thermometer inside the carboy? i've been thinking of picking one up to try it out...

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I don't think I'd try that. It would be very hard to read, and what if it broke in there? Those stick on thermometers are fine, or else maybe a digital probe thermometer down into the beer might be better. Just the probe submerged of course, and the thermometer part outside.

I usually have several batches going at different stages and have found that 5 g batches tend to run 2-3* higher than ambient and 10g batches run 2-4* higher during peak fermentation. after the first 3-4 days the temps stabilize on both sizes near ambient. I use the cheap stick on ones. I don't see any reason to have lots of money tied up in multiples of different thermometers that are only used at certain points of the process. I check my sticky ones with an infrared gun(that I use at work) every month.

I tape the sensor of my Digital Love Controller to the side of my bucket fermenters.

When I ferment at 65, it's 65 even when the ambient freezer temp is 55. The 10 degree delta only lasts a couple of days though, but that is when it is cranking.

I just set up my fermentation freezer this weekend and I'm wondering how I should set my temps and where I should put the probe. The freezer was one that was left at the house so I didn't have much choice on the size (until I decide to buy a bigger one) so I'm fermenting in 2 cornies with airlocks attached (I'll need to upload a picture of this, pretty good setup actually) and had about 1.5 gallons of wort left in the boil pot (oops!) so I have that in a 5 gallon carboy with aluminum foil over the top (airlock won't fit on it inside the freezer)

Anyway I'm using 3 different yeasts and I started with the ranco thermometer attached to the side of one of the cornies with some bubble wrap over it to get the beer temp. My fear though is that the other two fermenters will get too col (ambient was around 55 degrees with ranco stating 62 for the cornie).

Yeast are American Ale 1056, Nottingham, S-04. I know it will work out just fine but I am thinking the better way to do this would have been to dangle the temp probe in the freezer about mid-way down and set it at 60 degrees. That way the highest it can reach for vigorous fermentation is around 70 (using the numbers stated in this thread). When I have only one carboy/cornie in there perhaps I can tape the probe to the fermenter, but otherwise I'm thinking it is best to just regulate ambient temp? I imagine in such an enclosed space that I'll see the 2-4 degree difference mentioned here instead of the 10 degree possible, less room for temperature gradients.

Heat rises, so the higher in a freezer you put the probe the hotter it will be. I think the middle of it should work just fine. I have a love controller in my cabinet and have it dangling in the middle. Seems to work just fine. The beer is about 1-2 degrees warmer at most so I am not concerned.

i have my fermentation cabinet set for 58°F ambient. all the yeasts i use work well at that temperature and they keep in the low 60s during fermentation.

Fermometer, slapped on the side of the carboy/ale pail.

Thanks!

I also uses a fermometer when I can see it. I have ruined a couple with icewater bathes, I have had one survive with packing tape carefully placed over it, had another one die with the packing tape not so carefully put over it. Fermentation freezer is sooo much better

Right now I'm using my entire townhouse as fermentation room. Since I dont pay the electric bill (included in rent) I have the AC set to 65 so I can ferment my Fire Rock clone. SWMBO isn't thrilled about seeing her breath in the middle of summer but it's worth it to me

Displaced MassHole said:

Right now I'm using my entire townhouse as fermentation room. Since I dont pay the electric bill (included in rent) I have the AC set to 65 so I can ferment my Fire Rock clone. SWMBO isn't thrilled about seeing her breath in the middle of summer but it's worth it to me

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Oh man, I hope you don't lager like that too!!

No I've got a fridge in the garage for that, but right now its full of beer and dont have room for the carboy. Besides it's not like im trying to make a hockey rink in the living room

I use stickies on all my glass

I have an Infrared Thermometer:

Link

Point it at the carboy and get an instant reading. :rockin:

I just setup my fridge I got this weekend.. finally settled on 60 for the set temp with the probe submerged in a water bottle. The ambient is hovering around 56 and the fermenter is at 64.

I ferment in a chest freezer. I tape a folded up wool sock to the fermenter and stick a ranco probe directly on the fermenter insulated tightly by the sock. I will switch to a thermowell ASAP.

elowe said:

I have an Infrared Thermometer:

Link

Point it at the carboy and get an instant reading. :rockin:

I just setup my fridge I got this weekend.. finally settled on 60 for the set temp with the probe submerged in a water bottle. The ambient is hovering around 56 and the fermenter is at 64.

Click to expand...

i have one of those. works well for surface temps, which should be just as accurate as a fermometer.