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Old 10-10-2009, 05:06 AM   #1
Sep 2009
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I'm doing a Mild and after about 8 days I'm getting some of the Buttered Popcorn taste when I sample. The temp has been around 66-70 for the duration. Should I try to get the temp up to 72-74 for a 1-2 days prior to bottling to clean up the flavor?

I'm using an American Pale yeast and the FG has held at 1.018 (from 1.034) for 3 days now.

(I'm also considering adding a bit of sugar to give it a kick up into the 2.8-3.2 ABV range.


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Old 10-10-2009, 05:37 AM   #2
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Feb 2009
Louisville, CO
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The diacetyl is expected for this point of fermentation. You shouldn't need to raise the temperature and you can just leave it at that temperature for a few more days to reduce diacetyl. As far as the sugar goes, that's up to you. The sugar won't add flavor, but will dry the beer out more. For a mild, sometimes you depend on the high FG to give body to the beer.
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Old 10-10-2009, 06:14 AM   #3
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Mar 2009
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I was just listening to a podcast last night (either an old Brew Strong, or Jamil Show) and it was mentioned you can do one, but simply letting it sit on the cake for a little while at normal temps will do the trick. The guy speaking said he doesn't even do one for his lagers; he just lets them sit at 50 for an extra week or two. Now that I think of it, it was Jamil. There are very few people who can claim to have the knowledge he does, so I would go with him. I would class myself as entering the intermediate level, and I have never pulled off the cake in less then three-four weeks and I have never drank butter.
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Old 10-10-2009, 03:19 PM   #4
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Jun 2007
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another vote for just leaving it sit. your scenario is a prime example of why we don't want to rush beer. diacetyl rests are more common for lagers, because those cooler fermentations really stunt the yeasts ability to metabolize the diacetyl.

I usually am brewing lower abv beers that ferment quickly, but I tend to go 10-14 days in primary anymore. partially out of laziness, and partially because i know the beer can only benefit from chilling on the yeast cake. DO NOT FEAR the dreaded autolysis (burnt rubber and rancid death flavor), as it takes a LONG time for yeast to reach this point (well over a month).

remember that adding sugar will also thin the beer a bit, and dry it out a bit.
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Old 10-10-2009, 03:21 PM   #5
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Dec 2007
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I posted this info a long time ago on the best thread on D-rests on here; http://www.homebrewtalk.com/f13/prev...-please-70438/

The info is from;

By Moritz Kallmeyer"

The Abstract begins...

Diacetyl as a product of fermentation is more characteristic of ales than lagers. Diacetyl is produced early in the fermentation, and then most of it is reabsorbed by the yeast and reduced to flavourless compounds later on. Yeast strains differ markedly in their diacetyl reduction ability. Some ales and a few lagers (such as the famous Pilsner Urquell) contain perceptible amounts of diacetyl, but as a rule modern brewers consider it as a fault. This is because certain bacterial infections and other errors in brewing technique will increase diacetyl levels resulting in unacceptable beer aroma and flavour profile. This parameter thus serves as a quality check. However, it is important to remember that diacetyl flavour is a natural by-product of yeast fermentation, and in some beer styles it is an optional or even required flavour component in low amounts.
From here....

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There's two methods of rests listed in the Kallmeyer article...one for ales and warmer beers....interesting.

Maturation of beer flavour requires the presence of yeast as a catalyst. There are many methods of finishing that have the sole objective of prolonging the contact of beer with yeast after primary fermentation is completed. I want to emphasize that a diacetyl rest with most of the yeast lying at the bottom of the tank and not enough in suspension is of no use. Most lager breweries, especially those that use Weinhenstephan 308 or similar “diacetyl producing yeast’s” employ a long diacetyl rest, in order to minimize diacetyl in the finished beer.

Method 1
If a very cold primary fermentation was used it involves allowing the beer temperature to rise from the controlled primary fermentation temperature of about 10C to 15-18C when the primary fermentation is coming to an end. Normally, the time is determined by the attenuation of the beer. If, for example the wort starting gravity was 1050 and the expected terminal gravity is 1010, then the diacetyl rest would be commenced when the beer has attenuated to about SG 1023 when two-thirds of the total fermentable material in the wort has been consumed. The diacetyl rest normally lasts for 48-72 hours, until primary fermentation is over and secondary fermentation is under way. At this time the temperature is lowered when the more traditional method is followed, probably 1C per day until the lagering temperature of 0-1C is reached.

Method 2
If a warmer primary fermentation temperature was used for ale or lager the diacetyl rest involves either lowering the beer temperature 2 or 3C at the end of primary fermentation or keeping it constant for up to 6 days. In lager yeast strains with low diacetyl production it is common practise nowadays to employ a short diacetyl rest followed by centrifuging to remove excess yeast and then crash cooling to 0C. When brewing ales, that should have very low diacetyl levels especially German Ales like Alt and Klsch, the implications are to not use highly flocculent yeast and to allow an extended primary fermentation, albeit at cooler temperatures until sufficiently low diacetyl levels are reached. Yeast that settles in the cone is still removed on a daily basis.
Interesting for ALES one of the recomendations is to LOWER the temps a bit...or leave them at the same temp for 6 days...learns something new everyday...I'm going to have to try the cool rest.

It also backs up the idea of leaving beers on the yeastcake for awhile longer to allow the yeasts to clean up after themselves.
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Old 10-10-2009, 04:22 PM   #6
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Feb 2005
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I came back from travel once and tapped a keg to sample and it was buttery also.

After removing the keg from the keezer I released the pressure, removed the lid and added 1/2 tsp of dry yeast on top and closed the lid then let it sit in the garage for another 10 days. It was gone after that.

It ended up being a very good brew.
HB Bill

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Old 10-10-2009, 08:50 PM   #7
Sep 2009
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Thanks for all the responses guys. The part that made (is making) this difficult is that it is a Mild so it should be drank young in the first place. I guess I'll just see whats going on at day 12. The diacetyl was pretty light in the first place, so if its cleared by then I'll go ahead and bottle.

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