Temperature control

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Brews and Blues

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A common item I see on this forum is temperature control and the improvements it makes on the final product. Things have been confusing me with this item a bit.
1 - we are talking about the temperature of the fermenting wort and not the room temperature correct?
2 - what is more important, having a constant temperature or just keeping the temp in a certain range?
3 - I know that when the yeast begins working, the temperature can rise almost 5 degrees. So is the goal to counteract that rise in temp that naturally occurs to keep the beer at a constant temp?

I guess what i am getting at is that if my basement where i keep my fermenting wort is around 62 degrees, how much thought and time should i invest in temperature control since this seems to be right where you want fermentation to occur in most styles? Even a 4-5 degree rise in temperature due to fermentation keeps it right in the range. OR, does that fluctuation cause some off flavors?
 

VikeMan

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I'll answer this way:

- Good: Keep the temp of the wort/beer within the recommended range or some other range you have found works well for the strain/style. Live with the inevitable temp drop that will happen when fermentation slows (but is still going on), which might result in yeast dropping out a little sooner than otherwise.

- Better: Keep the temp of the wort/beer steady at exactly (or very close to) the temperature(s) you want, including a ramp up (if you want) to your main temp, a diacetyl rest/general cleanup temp toward the end (if you want), and a soft or hard cold crash (if you want).

Even a 4-5 degree rise in temperature due to fermentation keeps it right in the range. OR, does that fluctuation cause some off flavors?
Well, for example, if the yeast quits early due to a temp drop, you may be left with detectable diacetyl (also depending on yeast strain and other factors).
 

Beer Viking

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The temperature is that of the wort, not the room it is in. The wort will always be warmer then the room it is in. You will want to keep your temperature as stable as possible. There will be a range that the yeast you are using will be happy in, but there will be an optimum temperature that you should try to keep it at.
 

DVCNick

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62 ambient will be decent to good (at least) for the main active phase of fermentation for most ale yeast, but if you need any other temp you are still going to be lacking. I.e. if you wanted to do a lager lower, or ramp up an ale at the end to finish/d-rest as a lot of people like to do.

My house swings a lot depending on the season, so I got a craigslist chest freezer, Inkbird, and carboy heat wrap, and can now hold any temp I want within one degree regardless of the ambient temp. Probably less than $200 invested in that gear.

There is a lot of conflicting info and experience regarding exactly how much precise temp control matters for any given yeast, however, I think getting the ability to control it exactly is well worth it so you don't have to wonder what could have been if you had done xyz at a different temperature, etc.
Also, yes, temps referred to are always that of the fermenting wort, not ambient.
 

madscientist451

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I ferment in the basement (also about 62) , but then bring the carboy upstairs when it looks like its done to let the yeast finish up.
To cold crash, I put the carboy outside on the porch (during cold weather)
I also have temp control, but mostly use that for lagers or for summertime brews.
If you can only get one freezer, (with a temp controller) I'd use that for kegs and perhaps cold crashing and just use your ambient temps for fermenting.
If your kegs are all kicked, you could brew a few batches on one weekend ferment them in your one freezer, crank it down to cold crash and then just put your serving kegs in.
Its really nice to have two freezers or a freezer and an old fridge for fermenting/serving purposes, but not everyone has the space and money.
 

Deadalus

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The temperature is that of the wort, not the room it is in. The wort will always be warmer then the room it is in. You will want to keep your temperature as stable as possible. There will be a range that the yeast you are using will be happy in, but there will be an optimum temperature that you should try to keep it at.
Just to note, it is not always the case that the wort will be warmer than the room it is in.
 

Dland

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I guess what i am getting at is that if my basement where i keep my fermenting wort is around 62 degrees, how much thought and time should i invest in temperature control since this seems to be right where you want fermentation to occur in most styles? Even a 4-5 degree rise in temperature due to fermentation keeps it right in the range. OR, does that fluctuation cause some off flavors?
As said above, it is the wort temp one wants to control. In my experience if you have a 4-5 degree temp variation during fermentation, with most yeasts that will be OK, as long as that temp variation occurs within the optimal performance range of the yeast. When I say OK, that means it will likely be good beer, and if good beer is all you are after, you could probably leave it at that. If you are going for precise results and subtle target flavors expressed by yeasts at certain temperatures, that level of control might not be enough for optimal results.

With your example of a 62F ambient temp of cellar, and using US-05 ale yeast as example, you could expect the wort/beer to run at around 65-66F during active fermentation, and ease back to room temp of 62 as fermentation ends. Your beer would be fine. If your cellar were a bit colder or warmer than that, the temps would effect the flavor outcome with US-05 as yeast example. Certain esters that affect flavor often show up at the top & bottom of temp range between 60 and 70F.

In any case, it is quite easy and inexpensive to raise fermentation temp. All one needs is a Fermwrap heater or similar, and an inkbird 308 and some bubble wrap or other insulation. Moving beer around to different locations or changing styles with the weather are other options I've used in past also. For example, my cellar usually gets to high 40sF in winter, so I could make good lagers all winter with only ability to raise temp.

If you really get into it, and want to be able to dial temp right in for any style in any season, you will probably eventually get or rig refrigerated fermentation chamber(s), or as I did, make a glycol chiller.
 

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I guess what i am getting at is that if my basement where i keep my fermenting wort is around 62 degrees, how much thought and time should i invest in temperature control since this seems to be right where you want fermentation to occur in most styles? Even a 4-5 degree rise in temperature due to fermentation keeps it right in the range. OR, does that fluctuation cause some off flavors?
If the temperature in your basement is stable (61-63F) regardless of temperature changes 1) in other parts of the house and 2) in the outside weather, this approach can be used to make enjoyable beer.

If you decide to explore this approach further, consider recording wort temperature (stick on thermometer), room temperature, and external temperature during the fermentation.

Over time, you may find that certain strains of yeast "work better" than others in this approach.
 

A1sportsdad

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I guess I’m a little more anal about temperature control. I ferment in the basement where it’s about 68 F, but I use an Inkbird temp controller with a mini fridge to maintain my fermenter temperature at 64 F for the first 3 to 4 days. I have a thermowell in the center of the fermenter so I can measure the temperature of the wort. I don’t want the temperature to be able to ramp up during the active fermentation. After 3 to 4 days when the major fermentation is done, I remove it from the fridge and put a Fermwrap on it and bump it up to about 68 F. I leave it there for the balance to let it do some cleanup.
Obviously for different styles of beer these temps may vary, but this is generally where I try to keep it.
Temperature control is very important and the tighter you can keep it to where you want it the better off your beer will be.
 

NobleSavage

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Your basement temp is pretty good for fermentation. To help mitigate the temperature fluctuations in your wort, you could use a swamp cooler (as long as your fermentor doesn't have a spigot). If you have a cooler or large container that will fit your fermentor fill it with water and let it stabilize at your basement temp. Next time you brew, just put your fermenter in the bucket so that the water about 3/4 of the way up the side. The mass of the water around the fermenter will keep the temperature fluctuations to a minimum, and you can add ice packs or frozen water bottles if you want to chill it down a little.

I used to use something like this for 2.5 gallon batches (might be too small for 5 gallon), but you could even use a large rubber made bin.

Having said that, when I upgraded to a temperature controlled chest freezer for my fermentation chamber, the quality and consistency of my beers improved. This could just be in my head, but I went from making mostly good/very good beers with the occasional dud, to constantly making beers I am really proud of (where any undesirable flavors came from recipe creation not process).
 

Beermeister32

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Here’s some temperature control issues - the temperature probe of my controller was hanging outside the door of one of my lagering refrigerators!

The probe was supposed to be attached to the side if the keg. So it kept getting colder ... And Colder... AND COLDER .... 21F !!!!!!

So this morning I was greeted to a solidly frozen keg which I’m thawing out. Ice beer anyone??? !!!
54591459-4FC6-40BA-87CB-4034C3BFC78A.jpeg
 

DVCNick

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Ouch..... is that post fermentation? I bet that kills the yeast?
 

yowzers

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Solid temperature control doesn't have to use something as large as a chest freezer or fridge. You can use things like the Cool-brewing bag with ice jugs, The Brewjacket (which I've heard is pricey and a little slow to react) or I use this system. All totaled mine was $90 and it fits easily in a tiny closet under my stairs. Ball and Keg: Home Brew Keg Level Indicator
If you don't mind changing out one 2 liter jug of ice each day you can cool to any temperature for ales or lagers. I'm doing a lager at 58 F in my 68 degree basement as we speak.
 

Wolffie

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Here’s some temperature control issues - the temperature probe of my controller was hanging outside the door of one of my lagering refrigerators!

The probe was supposed to be attached to the side if the keg. So it kept getting colder ... And Colder... AND COLDER .... 21F !!!!!!

So this morning I was greeted to a solidly frozen keg which I’m thawing out. Ice beer anyone??? !!!View attachment 716447
I do like cold beer, how will that effect it when thawed?? flavor, carbonation, color, alcohol ?
 

jddevinn

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Woodstove. Room getting hot either from a heating system or the summertime sun. Lagering with ice.
So actively cooling it. The beer/wort will always be at the same temperature as the room, or if fermenting warmer. It cannot get cooler than the environment without something actively removing heat.
 

Deadalus

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So actively cooling it. The beer/wort will always be at the same temperature as the room, or if fermenting warmer. It cannot get cooler than the environment without something actively removing heat.
Yes, you can actively cool it say with ice bottles. However, under some conditions, the temperature of the room may rise considerably fast. Maybe your thermostat is set low at night but kicks on in the morning or you crank your woodstove up. Or it's the summer and the air conditioning is on all night and it is turned off as you go to work. We actively control the room environment with heating and cooling. It's possible for the beer to be cooler than the room while it adjusts to fluctuating room temperature.
 
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