Quantcast

What Is Diacetyl Rest?

Aussie Home Brewer

Help Support Aussie Home Brewer:

warrenlw63

Just a Hoe
Joined
4/5/04
Messages
7,202
Reaction score
11
am

Generally done at the end of a lager fermentation. Basically beer is warmed up a couple of degrees about 16-18c or so (say ale temps) for 24-48 hours.

The idea is the warmer temperatures drive off excess diacetyl. Usually always done before racking. Supposed to be a more ideal environment on the primary yeast cake.

(I'll leave the technical stuff to somebody else)

Warren -
 

Samwise Gamgee

Well-Known Member
Joined
27/1/05
Messages
538
Reaction score
0
Your right Drunk Arab!

I shouldn't be so f'n lazy, i did have a quick look (without search function) for diacetyl but should've gone that extra step.

Also, I've heard people mentioning you can find things a lot better on Google if you know how to look for them. How do you refine searches? As all I would've typed is: "Diacetyl Rest" or "What is diacetyl rest"

Cheers and beers!
 

Steve Lacey

Well-Known Member
Joined
24/2/05
Messages
374
Reaction score
2
am said:
Also, I've heard people mentioning you can find things a lot better on Google if you know how to look for them. How do you refine searches? As all I would've typed is: "Diacetyl Rest" or "What is diacetyl rest"

Cheers and beers!
[post="47350"][/post]​
Google works by looking for documents with all the search terms. Each individual word or group of words "enclosed in quotes" is a search term. It finds all web pages that match one or more of your search terms. Then it counts the number of times each term occurs. It may even look to see how close together they are in the page it finds them on. It then sorts them in order of numebr of times and closeness together. In other words, on what it callss relevancy. So if you put related words in increasing order of specificity, you will get better hits. For example,
beer brewing "diacetyl rest"
will give you a pretty good return, even if you leave out "lager", "home brewing" or other such possibilities. Google ignores words like "and", "is", "what". So your sugested "what is diacetyl rest" is probably equivalent to "diacetyl rest" as far as Google is concerned.

Hope you find what your looking for.

Steve
 

sosman

beerling
Joined
16/2/04
Messages
1,461
Reaction score
4
Steve Lacey said:
Google works by looking for documents....
[post="47352"][/post]​
I believe it also ranks them according to how many people click on them. But that is just an aside.
 

warrenlw63

Just a Hoe
Joined
4/5/04
Messages
7,202
Reaction score
11
sosman said:
Steve Lacey said:
Google works by looking for documents....
[post="47352"][/post]​
I believe it also ranks them according to how many people click on them. But that is just an aside.
[post="47354"][/post]​
Click or somehow sponsor. Sometimes I wonder. <_<

Warren -
 

rodderz

Well-Known Member
Joined
13/1/05
Messages
95
Reaction score
0
So would this treatment work on kit beers with a so called "lager yeast" as whats mentioned as being in the Coopers Bavarian Lager kit?
 

PostModern

Iron Wolf Brewery
Joined
9/12/02
Messages
5,293
Reaction score
16
rodderz said:
So would this treatment work on kit beers with a so called "lager yeast" as whats mentioned as being in the Coopers Bavarian Lager kit?
[post="47372"][/post]​
"Coopers kit" AND "lager yeast" returns only 19 hits in google. Interesting.

The first few google searches I tried made finding the definition of a diacetyl rest very difficult. Lots of hits recommending them but bugger all explaining them. I guess it's one of those things you pick up in fora by asking quetions like this.
 

dickTed

Well-Known Member
Joined
28/11/04
Messages
262
Reaction score
0
re-phrased question: How does Google work?
 

warrenlw63

Just a Hoe
Joined
4/5/04
Messages
7,202
Reaction score
11
rodderz said:
So would this treatment work on kit beers with a so called "lager yeast" as whats mentioned as being in the Coopers Bavarian Lager kit?
[post="47372"][/post]​
"So-called" would more or less be the best explanation for a Coopers Kit "Lager Yeast". Try the diacetyl rest as a matter of course. You've really got nothing to lose.

We're assuming that all the elements are in your favour anyway. eg; Lager pitching temps. Lager fermentation temps etc. When you try the finished product you may or may not have diacetyl. If you pitch and/or ferment too warm the yeast will create an excess of diacetyl that a warm rest will not reduce anyway.

Correct lager brewing is a pretty hard thing to get right if you let any of the other variables slip or don't have a dedicated refrigerator with some means of precise temperature control like a thermostat.

If you don't care for a diacetyl rest just let the beer cold condition for the standard 4-8 weeks or more and see what happens.

Here's a bit of info snatched from Gregory Noonan's "New Brewing Lager Beer" bit of an oxymoron given the fact it was published +10 years ago but still a fairly relevant book and highly-recommended if you're half-way serious about brewing lagers.


Six to fourteen days (six to ten days is usual) after pitching, the foam head begins to diminish as CO2 production falls off. Extract reduction should slow dramatically, and with a reasonably flocculant yeast strain the cell count will drop below ten million cells per milliliter.
If a diacetyl rest is being employed, force the temperature of the post-kraeusen ferment to rise to 55 to 60 degrees F (13 to 16 degrees C). After two days, lower the ambient temperature again, bringing the beer down to 38 to 40 degrees F (3 to 4 degrees C) at 3 to 5 degrees F (1 to 3 degrees C) per day.
When the extract drop slows to 0.5 Plato (SG 1002) over twenty-four hours, the head will have completely fallen. Rack the beer into a secondary fermenter/lagering vessel. The beer should be clear and bright. If the yeast does not seem to have largely settled out and still clouds the beer, then the yeast strain is dusty or mutated, the beer may ferment past end point, and it will probably need to be fined.


Warren -
 

redbeard

Sth Seas Pirate Brewery
Joined
23/1/05
Messages
1,132
Reaction score
8
rodderz said:
So would this treatment work on kit beers with a so called "lager yeast" as whats mentioned as being in the Coopers Bavarian Lager kit?
[post="47372"][/post]​
i think you'll find the supplied yeast in the coopers bavarian is the usual 'ale' type, as coopers recommend to keep the temp around 20'c, which is the lower end for ale yeasts. as such, i dont think you will gain anything with trying a Diacetyl Rest.

if you used a saflager or liquid lager yeast at lager temps ie 8-12'c then it would be a different story.

cheers
 

Trough Lolly

"Drink, Feck, Arse, Girls"!
Joined
21/8/03
Messages
1,692
Reaction score
7
am said:
...Also, I've heard people mentioning you can find things a lot better on Google if you know how to look for them. How do you refine searches? As all I would've typed is: "Diacetyl Rest" or "What is diacetyl rest"
G'day Sam,
Google is ok for general searches, but for me, I much prefer to search on hbd.org in the US. Ok, it's mainly yank brewers, but I found a wealth of info there that gives a wide variety of opinions on virtually any brewing topic you can think of. It's a great resource based on brewers experiences rather than rumour - although there's a fair bit of that flying around on it in places ;)

Here's the URL for the search page on HBD - you don't have to be a member to read the daily digests: Click here...
When the URL is launched, click on the dialog box that has "+host:hbd.org" text already in it and type something, eg, diacetyl, after the org, eg "+host:hbd.org diacetyl" and then click on the search button.

Don't change the search results list from "Standard" form. It will go off and launch an Alta Vista search, restricted to the hbd.org domain (so you won't get a hit on the new Japanese R&B all chick band called Diacetyl Banzai :super: ) and return all the hbd.org articles that mention your search text. From there, you can click on the links and learn all you want to know about that topic. It's that easy! :p

If you want to search on articles that include a number of key words, then you simply enter the search words, once again after the org, and separate them with commas, eg:

"+host:hbd.org yeast, 1028, harvest"

And for what it's worth, the original answer is spot on, IMHO - you want to raise the lagering temp to an ale temp to drive off the diacetyl notes that accumulate during the lager fermentation process - er, that's if the diacetyl notes are not in style with what you intend to brew...

Cheers,
TL
 

sosman

beerling
Joined
16/2/04
Messages
1,461
Reaction score
4
For an ale yeast, just keeping the beer on the yeast for a few days after SG fermentation has finished also constitutes a diacetyl rest. Whether you would notice a difference depends on other factors.
 

Latest posts

Top