Fermentation temperature question?

So the founder of my local homebrew league just informed me that if a recipe says to ferment at 67 degrees (F), you're actually supposed to put it in a room that's around 60 degrees (F), since fermentation itself actually produces 7-8 degrees (F)heat. Needless to say, I have not been doing this, and have had some problems with phenols.

I've read How to Brew and Designing Great Beers, along with countless online texts. Did I just completely miss the boat on this one, or...?

If this is true, it needs to be much much much more widely spoken about. Hell, a sticky might even be in order. In fact he told me "it's just one of those things you pick up over time, like you are now". I've been in the beer community for over a year, how has no one told me this until now?

Thanks in advance,
Kelly

I believe it has been discussed a few times on the occaisional thread related to fermentation temps. Basically when the yeast is highly active during the first couple days it is creating quite a bit of heat as it churns around and converts sugars. This will raise the wort several degrees above ambient temperature. This is usually evident if you have a fermometer attached to your fermentor. I noticed on my first batch of two that I was hitting in the 76-78 degree area in a 70-71 degree room.

The solution for me was to get a large plastic storage bin and fill it half way with water. I then set the fermentor in it with the level up 1/2 to 2/3 of the fermentor. I control the temp by occaisionally throwing some ice in the water and checking the water temp. The water against the fermentor is more effective at keeping temp constant than ambient air as the temp transfer is quicker and it takes some time for the larger volume of water in the plastic tub to begin rising in temp. I usually add a bit of ice once or twice a day. If you use an insulated container such as a large cooler instead of a plastic bin your temp keeps larger. I believe Yooper uses coolers with cutouts in the top for the neck of her carboys. I think some people also use a spare bathtub with water in it.

I think it's been made pretty clear that "fermentation temperature" is not ambient room temperature, but the actual temperature of the beer in the fermenter.

so I just completely missed that? man, I feel dumb.

edit: real dumb

size said:

so I just completely missed that? man, I feel dumb.

edit: real dumb

Click to expand...

Well, I didn't mean to make you feel dumb! Apparently, it wasn't as clear as I thought. I have those "stick on" thermometers on my fermenters, and they work ok.

One thing I've noticed that the warmer the fermentation, the "hotter" it gets. For example, if I'm fermenting at 62, I'll notice that it might creep up a degree or two during peak fermentation periods, so there isn't much of a difference between ambient and the fermentation temperature.

But, at 72, once fermentation kicks it, it can get very hot very fast. And of course, the more vigorous the yeast is, the more heat it produces, so it'll get even hotter. Fermentation produces heat, so it's a vicious cycle once it gets too warm. That's why I never pitch my yeast into a slightly too-warm wort- it might cool down before fermentation starts, but it probably won't.

Often when people mention that their beer apparently fermented overnight, I ask them if it was terribly warm. Usually, the answer is "oh, yes- the fermenter got up to 80 degrees!".

I've never had a beer fermenting under 64 degrees that needed a blow off tube, but in a warmer fermentation I have needed one.

I think temperature control is the single best thing I've ever done to improve my beer.

I have heard this as well. I have only been brewing since early this year. What I have been doing is fermenting at around 68-70 in the basement. So, I guess I have been really fermenting in the mid 70's(beer has turned out very good). I have never given it much thought about the heat given off during fermentation.

My question to the veteran brewers out there is this....Since the temp rises around 6-10 degress during active fermentation, what do you do about that? Do you ALWAYS use a swamp cooler in the summer because I am sure that you are not setting your AC in the low 60's? And during the winter is the coldest part of your house set in the low 60's? Or do you always ferment in a refrigerator?

Q2XL said:

I have heard this as well. I have only been brewing since early this year. What I have been doing is fermenting at around 68-70 in the basement. So, I guess I have been really fermenting in the mid 70's(beer has turned out very good). I have never given it much thought about the heat given off during fermentation.

My question to the veteran brewers out there is this....Since the temp rises around 6-10 degress during active fermentation, what do you do about that? Do you ALWAYS use a swamp cooler in the summer because I am sure that you are not setting your AC in the low 60's? And during the winter is the coldest part of your house set in the low 60's? Or do you always ferment in a refrigerator?

Click to expand...

If you want to control your fermentation temps and don't have an extra fridge, or don't want to get one, then a swamp cooler works well. I used one for a while before I started using a fridge.

If your beer turns out great to you, and don't mind or notice any phenols or esters, then keep doing what you're doing!

I've been blessed (?) with living in a cold climate. For beer, it's great. I can make lagers in the winter with very little effort. For ales, I use an aquarium heater in a water bath in a cooler in the winter, and a water bath and a few water frozen water bottles in the summer (if needed). There are pictures of my Ice Cube cooler set up in my gallery.

If someone is in a warmer climate, it's probably easier to have a small fermentation fridge dedicated to maintaining proper fermentation temperatures. I think the "son of a fermentation chiller" works very well, also.

Trubadour said:

If your beer turns out great to you, and don't mind or notice any phenols or esters, then keep doing what you're doing!

Click to expand...

Ha...I cannot tell the difference from a phenol from an ester from a fusel alcohol. I still have a lot to learn.

So, if we swamp cool our fermenter/primary, and the yeast manufacturer's suggested temp range 18-22C, then MY question is how long do we need to maintain that range with the swamp cooler? 1 week? 3 weeks? (I was planning on bottling after 3 weeks in the primary but just want to see what you guys think about how long to maintain the primary/fermenter's temperature?)

Thanks.

Bob-
1 week would be good - that's when the bulk of the fermenting activity takes place. After that, room temps should be sufficient, or so I hear on this board. Usually, I just leave it in my Fermentation Chamber (swamp cooler) at the same temps until I'm ready to keg.

Actually in a lot of ways a swamp cooler, or tub/container full of water is a more effective at keeping the temps down then a fridge because liquid is a more effective medium of transferring heat.

As to how long to control temps, I don't think storing beer at very warm temps is ever a real good thing. I usually keep my temp at 70-72 until I see the first signs of fermentation. Your yeast will get to work quicker at this temp and I have done some reading that suggests you not drop below 70 until fermentation begins. I don't think this is critical and YMMV, but this works for me. Once I see fermentation I usually begin adding ice to my container full of water to hit my desired fermentation temp. It depends on the yeast, but I usually go around 67-68 degrees. After a week or so I let the water come up to room temp which is usually around 70-72 for me. If it is very warm in the house I will try to keep the temp in the 70-72 area with a bit of ice. This temp is much easier to maintain after the main fermentation is done as the yeast aren't as active and are not generating all that extra heat. I understand after the main fermentation that the yeast may clean up more effectively back up around 70.

I try to keep my secondary in this range as well until I keg and go into the kegerator.

OK. So as Bob notes... if after maintaining at 20C for one week in the swamp cooler, can we let the fermenter get back up to room temperature, stop using ice, t-shirt over the fermenter etc? And, if we do this, will an average room temperature of 26-27C harm the beer? And also, what about the bottles? There is no way I can load up 10 swamp coolers with 30 bottles. So, does it matter if the bottles are conditioning at 20C or a room temperature of 26C?

Poincare said:

OK. So as Bob notes... if after maintaining at 20C for one week in the swamp cooler, can we let the fermenter get back up to room temperature, stop using ice, t-shirt over the fermenter etc? And, if we do this, will an average room temperature of 26-27C harm the beer? And also, what about the bottles? There is no way I can load up 10 swamp coolers with 30 bottles. So, does it matter if the bottles are conditioning at 20C or a room temperature of 26C?

Click to expand...

I have been reading recently that after the first 3-5 days of fermentation, temperature control is not that important - room temperature is fine.

I may have missed it but what is the trouble if you ferment at a bit higher temp? I start in my upstairs closet, temp of 74-76 after pitching. By am it drops to 72-74 and within 12 hours I am rolling and never surpass the 72 mark and within days sit at 68. For my secondary I hit the basement and run 64-66. It seems like most people run a bit cooler and I just wonder what effect it has.

Kelly,
I brewed for a long time and never talked much about fermentation temp. When I started, there wasn't an internet so you just picked it up at a homebrew store if you could find one, or more than likely, a book. I pretty much brewed for 20 yrs. doing partial grain ales. I have learned as much from this board as I did in all those years of brewing. All aspects of brewing are talked about on this board and technical issues are beaten to death. There is almost nothing that is universally agreed on here. Just remember, it's about fun. To quote Byron Burch "They were brewing beer thousands of years before they knew anything about bacteria (refrigeration), take reasonable care and you should be fine. Luck - Dwain

I bought a small bathroom vanity on sale at Home Depot for like 10 bucks and I put two layers of foam board insulation in it and it fits a carboy perfectly with 2 2ltrs of water next to it. Right now I've got an ale that was sitting around 74 or so and so I added 1 frozen 2ltr and it dropped the fermenter to 63 degrees. After I put it in it drops about 1 degree per day. I worry that I'm climbing and dropping temperatures too much, any thoughts?

https://cdn.homebrewtalk.com/gallery/data/1/medium/box_from_top.JPG

I live near Fort Worth, summer is eight months of the year and air conditioning is expensive. My laundry closet is a near constant 80 Fahrenheit. I use ice the first few days with a red pale ale and it’s fine.

I wrap a towel around the edge of a 6.5 gallon bucket, 4 or 5 inches hanging inside. I drop a 5 gallon carboy inside, and when the fermentation starts to become rapid I put ice on top of the carboy. Add ice 3 or 4 times a day until the fermentation slows down, about three days from the pitch.

My first batch, an all extract IPA, started out bubbling at a slow crawl in about 12 hours. By 24 hours it was found bubbling through the airlock quite furiously. I temped it at 80 degrees and promptly removed the towels from around the bucket. Are the undesirable effects of high temp during the first stage of fermentation or do they result from high temperatures throughout the entire primary?
What I mean to ask is, if I can bring the temperature under control now will it help reduce what may or may not effect my beer?

All you can do now is wait. Once a fermentation gets out of control it goes into thermal runaway and the yeast will eat most of the sugars very quickly. If you cool it now it’s just going to take longer. You might even shock the yeast and stall it. Remember they’ve been working at a very high temperature.

I’ll be interested to see what the guys think, but I would take a too-quickly fermented batch into secondary. It seems you might be getting rid off some nasty byproducts in the trub, and reducing an insane overpopulation of yeast.

I read somewhere that the fermentation reaction is exothermic on the order of 140 calories/gram. I brew three gallons at a time, with the fermenter iced down like a champagne bottle, and I can only get the temperature down to 75F in an 80F ambient environment. It’s a controlled runaway; the airlock bloops 30-40 times/min for about three days. It takes 10-12 pounds of ice.

I’ve done maybe a half a dozen batches like that, always 75F, with consistently good results. I’m guessing 75F is the magic number where runaway starts. Maybe I should ice it down a little sooner, but I worry that I would have to sit on this thing to regulate the temperature. The way I do it now, is once the thing takes off I keep it iced down until the gas tapers off. After that I let it go back up to 80F.

In my experience the wet towel/ cold bath method doesn’t do much. The only way I can brew in the summer is with the” ice it down in a bucket” method. That’s with ice on top and cold water all around. All the towel does is evaporate enough water that the bucket won’t overflow.

Cheers!

While the calendar may still say its summer, here in the NW my house has been a steady 70 degrees for more than a week and, because it is my first batch, I was worried it would cool off too much. I forgot my science lessons about exothermic reactions...
For the first 8 hours or so after it started bubbling it worked up to easily 40 bubbles a minute. I left and came back hours later and the airlock was going like a tire with a hole in it. Today it has evened out to 15-20 bubbles per minute. I am at 44 hours right now.
I too would like to know if there would be any benefit in racking to secondary at this point.

I can't think of a benefit that you'd get with racking to secondary. If it's not finished, it may stall the fermentation. Also, when the yeast is done with eating the fermentable sugars, it actually "cleans up" after itself, even digesting its own waste products like diacetyl. Leaving it on the yeast cake a bit after fermentation is over gives it time to do that. If it's fermenting too warm, you might just stress the yeast more by racking it and cause even more off-flavors.

Even after a day at a high temperature, it's always beneficial to cool the fermenter down to decent fermentation temperature. Sure, some damage as been done, but not as much as letting it sit at a too-high temperature.

I'd put the fermenter in a "swamp cooler", or at least a tub with water surrounding the fermenter (I use an Igloo cooler) and put a frozen water bottle in there. Most ale yeast have an optimum range of 62-70 degrees (the temperature of the beer, not the room!) but for more information, check the manufacturer's website. They have all the details about optimum temperature ranges for each strain, attenuation, flavors, etc.

I’m not convinced. I spent a summer brewing in an upstairs closet in Dallas. In my experience the trub on a hot batch is nasty, and I’d get off of it as soon as the active fermentation is done.

Sometimes it gets stuck here, going to secondary helps.

Is there something that happens in primary that wouldn’t happen in secondary? I mean besides off flavors.

As for the temperature, yeah chill it if you want to. Seems like a complete waste of time, you’re just going to slow things down. Realize that your yeast evolved in high temperature, they’re not the same yeast you pitched.