When to do a Diacetyl rest for lagers?

All correct, depending. I usually let it free rise starting at 4-5 points from final

 

There are too many factors here for an accurate answer... yeast strain, pitching rate, malt selection, and fermentation temp all influence the answer. Generally though, at the end of primary fermentation, you can let the temperature free rise. As long as you are past 50% attenuation, you won’t have any excess esters or fusels form. Frequently, raising the temperature isn’t necessary, but a couple extra days at fermentation temperature can clean up any remaining acetolactate or diacetyl.

 

Weedy, do you raise the temperature of your lagers at your brewery?

Cheers!

 

You can deep dive into all the variables. However, I'm going to guess that until taken outside of all the varying acepted options you wouldn't be able to taste a difference, even doing a triangle test, I guess no you statistical significance.

This is what I've done for all my lagers and I use there different strains, 2308 for Helles, 2124 for pils and WLP833 Märzen.

Pitch ferment at 50 deg F until fermentation slows, about 4 days. Raise temp 3 deg F daily, 1.5 in the morning and 1.5 in the evening, until 65 deg F. Hold at 65 deg F for 2 days. Cold crash and lager for 8 weeks.

 

I only really use Augustiner lager yeast and it ferments warmer than most lager strains and produces very little diacetyl, so not really. If I have a reason to believe a fermentation is a higher risk for diacetyl, I will raise it up, but that’s rare.

 

Never

 

Another vote here for never, but I only use 2206 and ferment at 45f with a 2.5ml pitch. It takes 5 days to get to 1% extract remaining, the is transferred to spund for 2. It is then at it’s terminal gravity, and fully carbed.

 

2.5 liter pitch?

 

2.5 x 106 cells/ml/°P
http://www.lowoxygenbrewing.com/uncategorized/lager-yeast-there-has-to-be-an-easier-way/

 

Haha okay, I knew 2.5 milliliters wouldn't be enough.

 

According John Palmer :

´Some brewers pitch their yeast when the wort is warmer and slowly lower the temperature of the whole fermenter gradually over the course of several days until they have reached the optimum temperature for their yeast strain. This method works, and works well, but tends to produce more diacetyl (a buttery-flavored ketone) than the previous method. As the temperature drops the yeast become less active and are less inclined to consume the diacetyl that they initially produced. The result is a buttery/butterscotch flavor in the lager, which is totally out of style. Some amount of diacetyl is considered good in other styles such as dark ales and stouts, but is considered a flaw in lagers. To remove any diacetyl that may be present after primary fermentation, a diacetyl rest may be used, and frankly, a diacetyl rest is good for every fermentation, both ale and lager. This rest at the end of primary fermentation consists of raising the temperature of the beer approximately 5-10F (2-5C) for 1-3 days towards the end of fermentation as the bubbling in the airlock slows down. In other words, if the fermentation has been bubbling steadily for the last couple days, but now it is slowing down, raise the temperature by moving the fermenter to a warmer area or adjusting your temperature controller. Allow the beer to sit at this warmer temperature for 1-3 days (or longer) before priming and bottling. This makes the yeast more active and allows them to eat up the diacetyl before packaging the beer and layering. Some yeast strains produce less diacetyl than others; a diacetyl rest is needed only if the pitching or fermentation conditions warrant it.´


It takes some time to learn the best moment to start a dyacetil rest for lager beers, I do it when there´s still a bit of fermentation activity (2-3 bubbles/min) and a 1 inch or less of foam atop the wort.I raise temp 6F until there´s no longer fermentation activity.

 

I got some Augustiner yeast recently. The stated temp range can go fairly high. What temperature do you recommend?

 

It really depends on the style. It is a versatile strain. In my Pils is start it at 52°F and let it work up to about 57°F. For my Dunkel I start at 55°F and let it get to 62°F

 

Thanks, probably will go low-ish.

 

YIKES, and Zee Germans shudder.

Size of your tanks?

 

I highly doubt they shudder as that was the technique they taught German students at Doemens when I attended.

15 BBL fermenters.

 

FWIW, here are the descriptions with the temperature range from 4 different labs that sell this strain:

-----Imperial Yeast:

"L17 Harvest
This strain combines good flocculation characteristics with low sulfur and low diacetyl. Clean fermentations produce amazing bock, helles, pilsner, dunkles, and just about any other lager style you throw its way.

Temp: 50-60F, 10-16C // Flocculation: Medium // Attenuation: 70-74%"

-----Wyeast:

"MUNICH LAGER II
™
Species: Saccharomyces pastorianus

From a famous brewery in Munich, this strain is a low diacetyl and low sulfur aroma producer. An excellent choice for malt-driven lagers.

MEDIUM
FLOCCULATION
72
-
74
ATTENUATION
52
-
62
TEMPERATURE RANGE
10
ABV"

------Omega:

"Thought to come from Munich’s oldest, traditional and vintage-vibed brewery. The Bayern Lager strain is clean, crisp and ferments well at a wide range. It has good flocculation, and has both low sulfur and low diacetyl production.

• Strain Type
  
  Lagers
  
  
• Flocculation
  
  Medium
  
  
• Attenuation
  
  72-76%
  
  
• Temperature Range
  
  51–62° F (11–17° C)
  

• Alcohol Tolerance
  9%"
  

-----BSI:

"Augustiner Lager 72-74% apparent attenuation • medium flocculation • 52-62°F fermentation range From the famous brewery in Munich. Low diacetyl and sulphur production."

 

Again, at what scale? We both know about hydrostatic pressure and suppression of esters.

Having made many hundreds of lager batches with ramps, and hundreds without, the hundreds with cold fermentation (45F) are hands down far and away better, in every aspect. Not even close actually. Home or commercial.

To each their own though. Congrats on Doemans.

 

Like I said... 15 BBL. Not really sure what response you're looking for. I've noted your strong opinions on lager brewing in the past. 45 degrees is below the recommended temperature for that yeast strain and was not recommended by German Master Brewers at a well regarded school for German brewers. At Doemens it was a 6 hectoliter system with open top fermenters. Every beer I've brewed with it has been brewed that way and every batch I've submitted to GABF and World Beer Cup has been judged very well and our dunkel had the highest score in competition history for Dunkels at Beverage Tastings Institute's World Beer Championship until this year where it is now 1 point behind the highest rated. Our Pils is in the top 50 for the style on Untappd with several of the "pils" ahead of it actually not being appropriate for the style due to their use of American and New Zealand hops.