How are You Measuring Fermentation Temperature?

[corkybstewart]

I've always just measured ambient too. I've got an Inkbird 308 regulating the temp inside a fridge holding my 14-gallon conical. The plumbers putty idea seems like a low-overhead method if it's really going to make a difference. Does the fermenter material matter? I notice in David Heath's video, he was demonstrating on a plastic fermenter - any reason to think a stainless steel fermenter would be different?

Stainless should be better, plastic has some insulating properties.

 

[ncbrewer]

Stainless should be better, plastic has some insulating properties.

Yes, I've found that from my readings. I use a plastic bucket fermenter. I find that the reading on a fermometer is about 0.9*F + 0.1*A, where F= Fermometer reading and A=Ambient temp (not including the fermometer correction). This is pretty crude, but close enough for me in my ale fermentation temperature range. If fermenting lagers, more accuracy would probably be needed, but my fermentations are normally in the mid to upper 60s during the active phase. After that, accuracy is less important.

 

[Clint Yeastwood]

Here's another problem. I was taught to pitch yeast at 70-80 degrees, but we generally ferment ales in the 60's and lagers in the 50's. So how much damage am I doing after pitching, while I wait for my fermenter to cool to ideal fermentation temperatures? It takes quite a while for 5 gallons of wort to go from 75 degrees to 65 in a refrigerator.

I've been reading that the temperature is most important during the a most active stage of fermentation. For some beers, that starts in a few hours. I pitched a heavy ale at something like 8 p.m., and the next morning, CO2 was blowing out of the fermenter.

Should we be making starters at fermentation temperatures? That would be a huge hassle. I would have to put my stir plate inside a refrigerator and let the cord hang out through the door, inviting garage bugs to visit. Should we make starters at room temperature and then chill before pitching? That could be hard on the yeast, if yeast is as fragile as people say it is.

Is the answer to pitch warm and start fermentation under pressure to reduce the fermentation by-products while the fermenter cools?

I ferment in Torpedo kegs, so I can pump a fermenter up with CO2 right after pitching if I want.

To make things more confusing, I just saw an interesting Brulosophy article in which lager yeast was pitched at different temperatures (80 and 48), and the writer said he preferred the warm-pitch results.

To add a final layer of complexity, I make a 73% wheat beer with WB-06, and when following my reckless methods and finishing at 68 (ambient), the off-flavors, if any, were too subtle for me to confirm. I would get all sorts of esters with a different beer.

 

[Ninoid]

How do people here measure the fermentation temperature of their beer?

When I got started back during the early 90s, I assumed that if a recipe said to ferment at x degrees, I was to set the fridge at x and not measure the temperature of the beer. I had no way to check on the beer itself. I figured everyone else did it the same way.

I haven't really changed anything, since the beer comes out fine.

If I see a recipe for beer, can I assume the listed fermentation temperature is the actual temperature of the beer, or are there old recipes that just give the temperature of the surroundings?

Seems like it would be difficult to keep the beer temperature steady, since the yeast will give off different amounts of heat at different stages of fermentation.

Are people using those little strips that stick to the sides of fermentation vessels, or what? I have laser thermometers, but they're not ideal for measuring the temperature of shiny objects like kegs. I have used a marker to blacken little spots on kegs, and I shine my laser thermometer at the marks. Don't know if it actually works.

I also use a laser thermometer to measure the temperature of the plastic fermenter. I know it's not very precise, but anyway, I don't have the possibility to regulate the fermentation temperature (a little air conditioning in the room where the fermenters are located for the hottest days), so it serves me only as an orientation.

 

[DBhomebrew]

It takes quite a while for 5 gallons of wort to go from 75 degrees to 65 in a refrigerator.

Faster when you're regulating FV temp rather than fridge temp. That fridge will continue getting as cold as it can get all the way down to FV @ 65 rather than calling a break when it gets to 65.

It takes just a couple hours for my 4gal batch to go from ~90-95 to mid-60s. Granted, that's in a freezer not a fridge.

 

[ncbrewer]

Here's another problem. I was taught to pitch yeast at 70-80 degrees, but we generally ferment ales in the 60's and lagers in the 50's. So how much damage am I doing after pitching, while I wait for my fermenter to cool to ideal fermentation temperatures? It takes quite a while for 5 gallons of wort to go from 75 degrees to 65 in a refrigerator.

How to Brew, E4 suggests pitching when the wort is at fermentation temperature. Yeast suggests pitching when the wort 1 - 3 F below fermentation temperature. Do you have the capability of cooling to the suggested range?

 

[corkybstewart]

Here's another problem. I was taught to pitch yeast at 70-80 degrees, but we generally ferment ales in the 60's and lagers in the 50's. So how much damage am I doing after pitching, while I wait for my fermenter to cool to ideal fermentation temperatures? It takes quite a while for 5 gallons of wort to go from 75 degrees to 65 in a refrigerator.

I've been reading that the temperature is most important during the a most active stage of fermentation. For some beers, that starts in a few hours. I pitched a heavy ale at something like 8 p.m., and the next morning, CO2 was blowing out of the fermenter.

Should we be making starters at fermentation temperatures? That would be a huge hassle. I would have to put my stir plate inside a refrigerator and let the cord hang out through the door, inviting garage bugs to visit. Should we make starters at room temperature and then chill before pitching? That could be hard on the yeast, if yeast is as fragile as people say it is.

Is the answer to pitch warm and start fermentation under pressure to reduce the fermentation by-products while the fermenter cools?

I ferment in Torpedo kegs, so I can pump a fermenter up with CO2 right after pitching if I want.

To make things more confusing, I just saw an interesting Brulosophy article in which lager yeast was pitched at different temperatures (80 and 48), and the writer said he preferred the warm-pitch results.

To add a final layer of complexity, I make a 73% wheat beer with WB-06, and when following my reckless methods and finishing at 68 (ambient), the off-flavors, if any, were too subtle for me to confirm. I would get all sorts of esters with a different beer.

So I'm not the most technical brewer around, I take my brewing seriously but don't get overly worked up on the science. Having said that I've entered 8 beers in legit competitions and have 3 medals and 2 beers made the finals. I pitch my yeast 3-5 degrees below fermentation temperature, and fermentation is at the low end of recommended temperatures. I don't have any scientific articles or research to back it up but this is the technique I have used for 25 years with great success. The temperature is going to rise, so I start low so there's a cushion for my cooling system to avoid getting overwhelmed.

 

[fluketamer]

i have a temp strip on the side of the fermenter.
when i use the ferm fridge in the spring and summer i tape the inkbird thermostat to the fv with foam reflectex .

when i just use the cellar in the winter and fall (55 to 59 degree. ) i tape a cheap meat thermomter to the side which is about 4 degrees off but i know that so it doesnt matter, lol

 

[BongoYodeler]

I currently use a Rapt Pill to measure the near real-time temperature of my fermenting beer. As of now I don't have a fermentation chamber per se, I'm using a Cool Brewing insulated fermentation bag. I swap in frozen 1.5L water bottles to keep the temperature as stable, and close to desired as I can, based on the Pill's readings. My goal is to eventually buy a used upright freezer and a heat belt and keep my fermenter in that, and use a Rapt temperature controller which gets its input temperature directly from the Pill, via bluetooth, and adjusts accordingly.

 

[Clint Yeastwood]

So I'm not the most technical brewer around, I take my brewing seriously but don't get overly worked up on the science. Having said that I've entered 8 beers in legit competitions and have 3 medals and 2 beers made the finals. I pitch my yeast 3-5 degrees below fermentation temperature, and I fermentation at the low end of recommended temperatures. I don't have any scientific articles or research to back it up but this is the technique I have used for 25 years with great success. The temperature is going to rise, so I start low so there's a cushion for my cooling system to avoid getting overwhelmed.

How do you get your starters down to those temperatures before pitching?

 

[day_trippr]

Cheers!

 

[Willy]

Inkbird sensor in the thermal well port if using CF-10. If using SS buckets or plastic buckets I use an ispindel and a thermometer tape on the side.

 

[corkybstewart]

How do you get your starters down to those temperatures before pitching?

I use the normal techniques to make my starter. But in the morning on brewday I put it in the fridge to make the yeast fall out so I can pour off the liquid. As I am pumping my cooled wort into the fermenter, I refill the starter flask with cooled wort and as soon as the fermenter is full I add the starter. Again, I have no scientific research to back it up as a good idea, but over the years I've tried a lot of different things and this is one that seems to help kickstart fermentation. Plus the idea of adding that old stale wort that is not what I'm brewing doesn't sit well with me. If I'm brewing a hefeweizen but I made my starter with DME, I don't want that DME in my beer.

I reread my post. What I meant is that when my wort is 3-5 below fermentation temp, I pitch the yeast, but it's at roughly the same temp as the wort.

 

[acrowe]

That's why one might measure the beer temp. Depending on size of batch and gravity, the beer temp can be 5+° over ambient. Your car's thermostat measures oil temp, not ambient, yeah?

Not really the best analogy. For most cars the thermostat doesn't actually give you a measure of temperature just opens and closes coolant flow at a particular set temperature.
The vast majority of cars actually give you an indication of coolant temperature not the oil temperature.
But it is true that fermentation is affected by the temperature of the fermenting wort/beer regardless of ambient temp.

 

[DBhomebrew]

Not really the best analogy. For most cars the thermostat doesn't actually give you a measure of temperature just opens and closes coolant flow at a particular set temperature.
The vast majority of cars actually give you an indication of coolant temperature not the oil temperature.
But it is true that fermentation is affected by the temperature of the fermenting wort/beer regardless of ambient temp.

Yeah, I was waiting for someone to call me out on that. Still, measuring coolant temp, not the air under the hood.

 

[Ninoid]

How to Brew, E4 suggests pitching when the wort is at fermentation temperature. Yeast suggests pitching when the wort 1 - 3 F below fermentation temperature. Do you have the capability of cooling to the suggested range?

I pitch the yeast a few degrees Celsius above the target temperature because the yeast needs some time to activate anyway so the temperature drops in the meantime.

 

[DonT]

How much has the beer improved?

A lot.... any real temp control can be a big step. My flex+ and glycol chiller now lets me change temp quickly and also lager, which the fermentation chamber couldn't do.... also improved oxygen avoidance and pressure ferm...

 

[Clint Yeastwood]

I think this thread will be very helpful to me with future batches. I'm thinking I should do exactly what I'm doing now with beers that already come out perfect, because you don't fix what ain't broke, but with beers I'm not completely happy with, I can use the foam thing and try to get my wort and starters down close to fermentation temperatures before pitching.

I make an ale that has a little more banana flavor in it than I want, so it would be a good place to start.

 

[Bassman2003]

Just get in the habit and do these things every brew. Make the starter at room temp, let it finish out and put it in the fridge the night before. Pour or siphon off the nasty wort/beer and pitch in your batch. Yeast prefer to go up in temp than down in terms of activity.

 

[ncbrewer]

Here is what's on my mind.

View attachment 864067

I like that concept. That's one reason I use dry yeast (in addition to concerns about shipping during the hot months and shorter shelf life). Starters aren't an issue - hassle is zero.

 

[Yesfan]

How Are You Measuring Fermentation Temperature?

* licks finger, sticks finger in the air *

"Yep, better dial her down a bit. She's uh running hot."

* Turns the HVAC temp down 1 degree. *

 

[Flushot22]

I use an All-rounder fv with an $.50 external sticker thermometer and a $60 Rapt Pill floating in the wort/beer.

 

[Kickass]

I'm thinking I should do exactly what I'm doing now with beers that already come out perfect,

Hahaha, face palm!

While I agree with the “if it ain’t broke…” that was a very long way to get there.

 

[bike2brew]

SsBrewtech bucket with cooling coil and swamp chiller. Thermowell probe and Tilt hydrometer for monitoring. They are generally within a degree or so of agreement. Yes, temperature control has been the most important variable in quality of my beer.

 

[Clint Yeastwood]

Hahaha, face palm!

While I agree with the “if it ain’t broke…” that was a very long way to get there.

You left out the part where I said I was making changes.

 

[Kickass]

I suppose you’re right, I missed the references to the foam thing and chilling starters/wort to pitch temps.

 

[Knightshade]

I tape an inkbird probe to the side of my keg which has a little insulating pocket I sacrificed from an old beer koozie. It is set to a 1.5 degree differential based on what my Tilt is telling me is the internal temp.

Forgot that I had a recent pic which speaks to this.

https://cdn.homebrewtalk.com/data/attach/804/804760-IMG-0729.jpeg

 

[worlddivides]

Just got a thermowell and temperature controller + probe, and it's been interesting to compare the temperature sticker on the side of the fermenter with the probe in the thermowell. When I was bringing down the temperature as quickly as possible, there was about a 1 degree Celsius difference (about 2F), but once it stabilized, they match up, though the probe goes in 0.1F increments, while the sticker only does 1C increments, so it can be difficult to compare the exact difference between them.

Ever since my very first brew turned out tasting like cloves and bananas, I realized just how massively important temperature control is (I've never been a fan of Hefeweizens and this was not a Hefeweizen), though I've mainly done it with fermometers / temperature stickers and just fermenting so that the sticker shows the lower range of the fermentation range. So even if the temperature inside the fermenter is 5, 6, 7, 8 degrees warmer, it's still only in the middle of the temperature range. For example, the sticker says 62F when I'm fermenting an English ale and I've assumed it's around 63F or 64F, but even if it was 70F, it's still not going to cause any harm to the beer, just a slightly different (though still desirable) character. Now that I have a thermowell and temperature controller (which I mainly got to prevent the wort from getting too cold in the winter time - I have it hooked up to a Brew Belt), I'll be able to see if the differences get any bigger than the 2F / 1C differences I've been seeing.

 

[DuncB]

Should we be making starters at fermentation temperatures?

No not really.
https://suigenerisbrewing.com/index.php/2022/09/20/optimizing-yeast-starters/

 

[SpeedYellow]

Brew Bucket with thermowell and probe going to a digital controller. All sitting in a freezer, with aquarium heating pads wrapped onto the fermenter. So the fermenting beer temp stays within a degree or so of the set point throughout the fermentation.

 

[worlddivides]

I've been monitoring the temperature of the probe in the thermowell and comparing it against the stickers on the side of the fermenter, and they're usually a difference of about 1 degree Fahrenheit. For example, the thermowell currently reads 58.1F, while the sticker on the side reads 57F. And this is at the height of fermentation (3 days after fermentation started) with quite a bit of constant airlock activity. I've always just used the stickers, knowing that it was influenced to some degree or another by the ambient temperature but thinking that it was close enough, and it seems that's the case. That said, I imagine a really violent and explosive Belgian ale yeast fermentation around 80F would probably have a bigger difference between the probe in the thermowell and the sticker on the side of the fermenter, though I'm not sure whether it'd be a 2-3F difference or a 5-6F difference. People always say "not ambient temperature," but those stickers only show the ambient temperature when the fermenter is empty. When you've got fermenting wort in there, the ambient temperature might be 70F, but the sticker says 62F (and the actual temperature in the fermenter might be 63F).

 

[DBhomebrew]

I've been monitoring the temperature of the probe in the thermowell and comparing it against the stickers on the side of the fermenter, and they're usually a difference of about 1 degree Fahrenheit. For example, the thermowell currently reads 58.1F, while the sticker on the side reads 57F. And this is at the height of fermentation (3 days after fermentation started) with quite a bit of constant airlock activity. I've always just used the stickers, knowing that it was influenced to some degree or another by the ambient temperature but thinking that it was close enough, and it seems that's the case. That said, I imagine a really violent and explosive Belgian ale yeast fermentation around 80F would probably have a bigger difference between the probe in the thermowell and the sticker on the side of the fermenter, though I'm not sure whether it'd be a 2-3F difference or a 5-6F difference. People always say "not ambient temperature," but those stickers only show the ambient temperature when the fermenter is empty. When you've got fermenting wort in there, the ambient temperature might be 70F, but the sticker says 62F (and the actual temperature in the fermenter might be 63F).

Cover the sticker with a piece of insulating foam. It will close the gap between it and your thermowell.

 

[ncbrewer]

but those stickers only show the ambient temperature when the fermenter is empty.

Have you checked it with an empty fermenter? If it doesn't read ambient temperature, you will know what the fermometer correction is.

 

[worlddivides]

Have you checked it with an empty fermenter? If it doesn't read ambient temperature, you will know what the fermometer correction is.

I have. It's the same as ambient for the closet-type area where the fermenter is kept (albeit, again, these fermometers only basically display by 1 degree Celsius or I think in Fahreinheit, it goes in 2 degree increments).

 

[ncbrewer]

FYI - The fermometers I've used are marked every 2 degrees, but it there is a blue indicator instead of green, the temperature is between the blue and the brown. So you can read to 1 degree. And if it's turquoise (blue-green), I call it to the nearest half degree. That's not in the instructions, but it makes sense to me.

 

[Clint Yeastwood]

I put a batch of ale in the fermenter last night, and I used the foam and tape method. I can't tell you for sure it's working, but the fermenting fridge smells more like plain old fermentation than bananas.

 

[Clint Yeastwood]

Well, it turns out tape does not like sticking to Torpedo kegs. This afternoon, the foam fell off. I tried electrical tape. No good. I tried medical tape--the stuff you can never get off your skin once you put it on--no good. I could not find the duck tape or gorilla tape.

I asked myself what kind of adhesive sticks to things that are wet.

Now the probe is back in place, held there by two big gauze bandages. The self-adhesive bandages they make these days will stick to anything.

 

[day_trippr]

fwiw, I use 2"x24" Velcro cinch straps for such efforts. One for kegs, two doubled up to reach all the way around my carboys...

https://www.amazon.com/24-Inch-Cinch-Straps-Pack/dp/B00VETHHY8/

Cheers!

 

[worlddivides]

FYI - The fermometers I've used are marked every 2 degrees, but it there is a blue indicator instead of green, the temperature is between the blue and the brown. So you can read to 1 degree. And if it's turquoise (blue-green), I call it to the nearest half degree. That's not in the instructions, but it makes sense to me.

You know, I've noticed that since my very first brew over 10 years ago (since the very first kit I got was a glass carboy MoreBeer kit that had a fermometer on it), but for some reason, because they were marked every 2 degrees, I focused on that fact and forgot the fact (one I notice every single time I look at it since it's kind of hard to not notice the different color) that the color is different when it's in between the two marked degrees. But yeah, excellent point. The main thing is that I've always thought they were pretty accurate, but it turns out they're a lot more accurate than I thought. Not perfect, of course, but within 1-2 degrees of the probe in the thermowell (so far, usually around 1 degree off).

 

[Bassman2003]

Well, it turns out tape does not like sticking to Torpedo kegs. This afternoon, the foam fell off. I tried electrical tape. No good. I tried medical tape--the stuff you can never get off your skin once you put it on--no good. I could not find the duck tape or gorilla tape.

I asked myself what kind of adhesive sticks to things that are wet.

Now the probe is back in place, held there by two big gauze bandages. The self-adhesive bandages they make these days will stick to anything.

Try the plumbers putty if you have any.