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Yeast Fermentation Temperature

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BoilerUp

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I know that temperature is important when fermenting but I have a few other specific questions. Please be as detailed as possible.
1. What happens when temperature fluctuates when fermenting?
2. If a temperature is higher or lower consistently over the time period of fermentation, what happens?
3. What is the range of temperatures that will affect my beer? (ie two degree's outside the range?)

Thanks for the help and cheers.
 

steelerguy

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1. The yeast will metabolize the sugar differently creating different flavors at different ranges.
2. If the temp is kept on the low end of the yeasts comfort range it will generally produce a clean beer which is true to character. If it is fermented on the high end it will usually create more esters and even fusel alcohols which can make it taste like you have bananas and rubbing alcohol in your brew. This is VERY dependent on the yeast strain used and even the fermentables, so it is a generic answer.
3. 1 degree will affect your beer, but maybe not to the level you could tell. I would look the strain you are using up at the manufactures website and keep it in that range for sure and even aim for the middle of the range. A lot of yeast will make the same type of flavors over a large range. I have used some Belgian yeast and controlled the flavor of the beer by varying the temperature even though the yeast was happy over the entire range.
 

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It will be easier to help if you tell us what kind of beer. For instance, with a Belgian you may want the esters that come at high temps. With a pale ale, you probably don't. What kind of beer are you asking about?
 
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It will be easier to help if you tell us what kind of beer. For instance, with a Belgian you may want the esters that come at high temps. With a pale ale, you probably don't. What kind of beer are you asking about?
I'm brewing a brown ale with WLP005, unfortunately I live in an apartment with extremely limited space and temperature control :( (side note: any suggestions for that?). It's been 36 hours since I closed the lid and fermenting quite vigorously and is at 71 degrees F. I'm just concerned, my last two beers have been less than ideal, however the last two times I used dry yeast.
 

McGarnigle

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There's nothing wrong with dry yeast, so that shouldn't have been the problem with those beers. Is 71 degrees the temperature of the room or of the fermenter's inside? If the latter, that's nothing to freak out about. If the ambient temp is 71 and the fermenting temp is closer to 80, then that's more of a concern.

Using a swamp cooler can help bring your temps down a few degrees. Search the forum for 'swamp cooler.' Many posts will be about using one to lager, which shows how effective they can be.
 

steelerguy

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I'm brewing a brown ale with WLP005, unfortunately I live in an apartment with extremely limited space and temperature control :( (side note: any suggestions for that?). It's been 36 hours since I closed the lid and fermenting quite vigorously and is at 71 degrees F. I'm just concerned, my last two beers have been less than ideal, however the last two times I used dry yeast.
Here is what I did for temperature control up until yesterday when I bought a chest freezer:

https://www.homebrewtalk.com/f51/smaller-son-fermentation-chiller-79556/
 

HotbreakHotel

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When the temp is lower the yeast will ferment cleaner. When it's higher, the yeast will produce more esters, which you probably don't want alot of with WLP005. 71 degrees isn't that bad. If you detect anything you don't like it will probably condition out. Below 68 or so is better, it will be cleaner.

As far as I understand, it doesn't give the yeast extra stress to fluctuate a few degrees, but the times the yeast is out of range it will produce undesirable esters.

To answer your #2, if you can consistently keep your fermentation below 67-68 (down to 62 or so) it will be real clean, and if you consistently keep it higher you might get a little something you don't like if you're picky, but it will condition out unless it was way too warm.

When I first started brewing I thought I needed to keep ales at 72 degrees, and the beers did taste good when young, except when I burped I'd taste a little banana or something. My husband said he didn't detect it.

In short, IMHO I think your ale will be fine fermented at 71 degrees, but if you're picky you might want to condition it a little longer. I wouldn't let that temp stop me from using WLP005. If it's going to be 73-80 I'd brew a Belgian or Hefe.
 

brian_g

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I'm brewing a brown ale with WLP005, unfortunately I live in an apartment with extremely limited space and temperature control :( (side note: any suggestions for that?). It's been 36 hours since I closed the lid and fermenting quite vigorously and is at 71 degrees F. I'm just concerned, my last two beers have been less than ideal, however the last two times I used dry yeast.
If your having difficulty controlling your temperature, I would suggest staying away from the fancy liquid yeast. Stick with a generic yeast that is forgiving. There is no sense in spending $6 on yeast, only to have it get too hot and your beer coming out tasting like bubble gum.
 

ifishsum

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If your having difficulty controlling your temperature, I would suggest staying away from the fancy liquid yeast. Stick with a generic yeast that is forgiving. There is no sense in spending $6 on yeast, only to have it get too hot and your beer coming out tasting like bubble gum.
I mostly agree with this. I started brewing last summer and at first really struggled to keep my fermentation temps under control (and my beer to really taste like it should). The most forgiving yeast to me seemed to be Safale US-05. I got some real tasty batches using that even when I was a bit over 70* but it is much better if you can keep it in the 64-65* range (wort temp not room temp), at least for the first 5 days. Once the most active part of fermentation is over it's not as critical. Try the swamp cooler/wet T-shirt method, it really does help keep it a few degrees cooler.
 
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Thanks for the reply's, lucky for me the temperature has cooled in the last few days, so I think i'm in the clear.
 

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The biggest improvement in my beers came when I realized how much of an effect fermentation temperatures have on taste. When I first started brewing I would pitch the yeast, stick the fermentor in a warm corner of the laundry room and leave it there. As it turns out, that warm corner would sometimes get up around 75 degrees and my beer would come out with some very un beer-like flavors. Now, I pitch at 75-80F to get things going and put the fermentor in a corner of the basement where it's a more beer friendly 65-68 degrees.

I've also switched to liquid yeasts which seem to ferment much slower. Between the liquid yeasts and the cooler temperature my active fermentation can last up to a week and a half instead of a couple days like it was with dry yeast and warmer temps.

Tom
 
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