Ferm Temp

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shibbypwn

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I'm new to brewing, and I've spent a lot of time browsing the forums here... I've noticed a lot of people talking about fermenting at a certain temperature, and then slowly raising the temp as fermentation goes on.

I.e. 66 degrees in primary, 68 towards the end of initial fermentation, 69 in the secondary, 70 in the bottle

Can someone explain this to me? How do I figure out an optimal temperature schedule for a brew considering yeast type and beer style.
 
Has more to do with yeast strain, type, brew you're going after, etc... There's no set method for any of them, well except when you lager...

Just like you can have a dozen people brew the same recipe, use the exact same yeast, but you'll get at least 6-8 different treatments of the wort and yeast once pitched. People will ferment at different temperatures, leave on the yeast for different amount of times (read up on the long primary, no secondary method) etc... Come back once it's all carbonated up (people can also use several different priming solutions and amounts) and you'll have at least 8 different brews. Most likely, each brew will be different enough to be detected.

So, while I might leave a brew at a set temperature, or range, while fermenting and on the yeast. Someone else (perhaps with a fermentation chamber) will do the different temps at different times... Both methods are 100% valid. Neither is more right than the other.

Basically, RDWHAHB... :mug:
 
The above post makes a good point that a fermentation schedule will vary from style to style, yeast to yeast, and system to system, so there really is not a "stock" answer. I can offer you the details of a schedule that works great for me using WLP001 (Chico Strain) for an American Ale here....

https://www.homebrewtalk.com/f163/when-let-temp-raise-safale05-231364/

The outline I provided does make the assumption that you have some pretty advanced equipment that affords you super precise temperature control. The link above is the long answer. The following is the short answer. I think it is safe to assume that being new to the hobby, you are still working within the confines of basement temperature, or an interior closet. If that is the case, I suggest you ignore the discussions about increasing temps over the course of fermentation in favor of a cool, steady temperature, and leave it be for a minimum of 3 weeks, and maybe a maximum of 5. Longer than three weeks will not really hurt you, but I really think that returns start to diminish. I'd imagine an ambient temp of 64F is a good compromise throughout the process, because it will be warm enough to keep the yeast from completely falling out of suspension during conditioning, yet cool enough to avoid the ester danger zone you will enter in the mid 70's. Carrying the carboy all over your house searching for 63, 65, 67, 70F, will just confuse the yeast, so I do not suggest it. Besides, ambient is a really poor gauge for someone trying to run a fermentation temperature program.

That said, fermentation control should really be your next investment. You can easily set up a small chamber for far less than the cost of that fancy new Blichmann kettle, and it will make a much bigger difference in your finished product. A dorm fridge, Johnson Digital Controller, and fermwrap can be had for about $250. Making wort is easy; the fermentation is what makes or breaks your beer. The 1-2 punch of PBW and Star-san won't hurt either. If I could start over, I would have been doing full wort boils with extract and fermenting in my controlled fermentation chamber long before I moved to all-grain.

Joe
 
Sometimes the recipe for call for a particular yeast and fermentation temp schedule. ie. I'm brewing a Wittebrew using a recipe out of 'Brewing Classic Styles' It calls for WLP400 and to start fermentation at 68 and slow raise it to 72 by the end. Now, its kind of arbitrary to determine when the end is. Another thing you can do is search the forum for the yeast your using and see what temperatures other folks have had success with. I'll also look at the White Labs yeast reviews (if I'm using White Labs) and often the reviews will have some info as to the temps users have tried. Wyeast and White Labs will also have better info on their websites as to the best fermentation conditions for the particular strains. Good Luck!
 
Gotcha. What is the purpose of raising temps? Just to keep fermentation moving steadily?
 
It is not so much raising temps as it is slowly getting up to the desired temperature. My temperature outline has nothing to do with a Diacetyl rest, so be careful not to confuse the two. If you want to use a d-rest, you will go ABOVE the fermentation temperature to encourage the yeast to increase activity and speed up the process of cleaning up biproducts from the fermentation cycle. I do not find it is neccessary in my process, because I keep the temperatures low during growth so off-flavors are minimal. I also have come back to practicing the long primary which also aids in conditioning away biproducts. Long story short, no d-rest needed.

As I noted, I am pitching well below where I intend to ferment at in order to suppress esters that form during the growth phase (the first 24-36 hours) of fermentation. It is especially important when using an English strain that can come off as overly "ester-ey" if growth happens at too high a temperature.

Look at Brewing Classic Styles. If it suggests fermenting a beer at 68F, 68 will be the highest temperature I reach during the fermentation program, not the lowest temperature.

Joe
 
Yeah, higher temps can do a couple different things. Some yeasts tend to need a little higher temp at the end of fermentation to finish fermenting out the sugars. Sometimes high temps can lead to esters, although a lot of the time these are put off during the growth phase, which is right after pitching, which is why you see a lot of people saying to keep it cool at the beginning and then allow to warm up. Of course, other yeast strains (Belgians, hefes, etc.) need the esters, so some people will really ferment them high the whole time.

What I used to do is use a swamp cooler (tub with water in it to set the fermenter in). At the beginning, I'd toss a few ice bottles into the water to keep the fermenter cool, but after about a week or so I'd get tired of doing that twice a day and just stop, allowing the temps to rise to ambient ;). Not sure if it ever really did anything, but it excused me not changing the ice bottles for three whole weeks!
 
Personally, I like to ferment at the low end of the yeast's optimum range, for cleaner flavor. It can extend the amount of time it takes to finish the fermentation, since the yeast are eating slower.

But once the bulk of the fermentation is complete, the yeasts won't be making much off flavors, so it's safe to raise the temp. Gradual is better, so they say, but getting it higher can help the yeast perform a cleanup of their by-products a bit faster.

This is mostly for ales. Lager yeasts might need a D-rest between the initial fermentation and the lager stage. If you start fermentation at the lower temp, you probably won't need one, and can go straight to the lagering stage, which is a bit LOWER in temp.

And there is the odd case of say a Saison, which could be started very warm, in excess of 90 degrees to get the funkiness that you want.

The consensus is that it's best to keep your temp as even as possible and make any temp changes gradually. Exactly what gradual means is probably debatable. I think as long as you are not suddenly cooling the yeast into hibernation, you should be ok.
 
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