WHEN to D-rest!? Help

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ScottMathsonPro

ScottMathsonPro

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I have a Maibock Lager in the fermenter right now. Yeast (Safale W 34/70) was pitched on the warmer side on May 24th. Fermentation and blow off action took off well within the first 24 hours. I got the temps down and as of today, the 28th, it is sitting at 54 degrees Fahrenheit.
This is my first lager and I have been reading about a much needed "d rest".
But when!? How will I be able to tell when it's about the last two days of fermentation to do the rest?
As of right now, it bubbles in the fermentation lock every 7-9 seconds or so.
In advance, thank you for your help and responses!
 
What was you're OG? When you get to 75% done then d-rest...that's what i was told on here by those who know !!!!
So you get your OG & expected FG and work out what 75% is, then you rest it before racking & lagering

If I'm wrong I will be corrected by more experienced brewers :)
 
Fermenting warm for the first 4 days defeats the purpose of using lager yeast. That's when all the growth/ester development occurs. You're also likely to develop excess diacetyl this way.

If you pitch cold (44F) with the correct amount of yeast you won't have to worry about this stuff.

In this situation, warm it up when the batch has reached 75-80% attenuation. This may help clean up at least some of the off flavors.

If you need a blow-off tube for a lager, you're fermenting much too warm. A Maibock should start at 44F and slowly rise to 50F, going slow and steady for about two weeks. No need to go above 50F if you pitch the right amount of yeast.
 
g-star said:
Fermenting warm for the first 24-36hrs defeats the purpose of using lager yeast. That's when all the growth/ester development occurs. You're also likely to develop excess diacetyl this way.

If you pitch cold (44F) with the correct amount of yeast you won't have to worry about this stuff.

In this situation, warm it up when the batch has reached 75-80% attenuation. This may help clean up at least some of the off flavors.
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Exactly. Pitch a proper amount of healthy yeast. Start cool and warm slowly(extreme generalization). Shouldn't need any sort of d-rest. Just a standard lagering time.
 
The d rest seems some what allusive. Why do it? Can't you just let the wort sit in the primary for a while after it's done fermenting at the normal fermentation temps and call it good?
 
g-star said:
You're also likely to develop excess diacetyl this way.
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? I thought diacetyl was produced due to cold conditions, which is why folks do a d-rest and warm the beer up. Off flavors from too warm a fermentation yes, diacetyl no.
 
As soon as you see the krausen even begin to drop, warm it up to basement temps. Or room temp if you have no basement. Leave it on the yeast cake 3 weeks. Rack.
 
phoenixs4r said:
? I thought diacetyl was produced due to cold conditions, which is why folks do a d-rest and warm the beer up. Off flavors from too warm a fermentation yes, diacetyl no.
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Well, I can only speak from my experience. I never do any kind of diacetyl rest, and I pitch cold (43-44F). I then let it rise over 36hrs to 48-50F and hold it there. After 2-3 weeks, depending on OG, I rack to a keg and begin lagering.

The key is to pitch the correct amount of yeast...which is A LOT. I have never had any diacetyl problems this way. The one time I did, I pitched warm (60F), and then tried to cool it down once it kicked off, after about 24hrs. By then it was too late and I had the dreaded buttery O-fest.

People warm up their lagers for a d-rest to encourage the yeast to clean up the off flavors they created in the first place by pitching warm and/or not enough yeast.
 
g-star said:
People warm up their lagers for a d-rest to encourage the yeast to clean up the off flavors they created in the first place by pitching warm and/or not enough yeast.
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Not necessarily! Although pitching cold is my preference, that's not because of diacetyl. It's because of ester production and other off flavors.

Some yeast strains are notorious for producing diacetyl, even if pitched appropriately and fermented at the correct temperatures.

Sometimes a diacetyl rest may not be needed, but it never hurts to do one.

Pitching a lager too warm and keeping it there for several days isn't really going to create much more diacetyl, as much as esters and other byproducts of fermentation.
 
Alright so I did find info on my recipe and OG should be anywhere between 1.072-1.076
FG anywhere between 1.016-1.020
I'll try to figure out the 75% point and take a reading.
 
g-star said:
Well, I can only speak from my experience. I never do any kind of diacetyl rest, and I pitch cold (43-44F). I then let it rise over 36hrs to 48-50F and hold it there. After 2-3 weeks, depending on OG, I rack to a keg and begin lagering.

The key is to pitch the correct amount of yeast...which is A LOT. I have never had any diacetyl problems this way. The one time I did, I pitched warm (60F), and then tried to cool it down once it kicked off, after about 24hrs. By then it was too late and I had the dreaded buttery O-fest.

People warm up their lagers for a d-rest to encourage the yeast to clean up the off flavors they created in the first place by pitching warm and/or not enough yeast.
Click to expand...

Interesting and this definitely sounds like a problem I may run into, as I did pitch it on the warm side, then cooled temps. I appreciate your input and expertise.
 
For what it's worth, a ahile back I asked the brewmaster of Red Oak, a local reinheitsgebot Bavarian lager brewery, if he did a diacetyl rest. It almost seemed an insult to him. He said that it is not needed after a proper fermentation. I can't remember his exact explanation. I know he pitches cold.
 
jeepinjeepin said:
For what it's worth, a ahile back I asked the brewmaster of Red Oak, a local reinheitsgebot Bavarian lager brewery, if he did a diacetyl rest. It almost seemed an insult to him. He said that it is not needed after a proper fermentation. I can't remember his exact explanation. I know he pitches cold.
Click to expand...

From the information I've found here (yooper etc) if it's a cold pitch and a proper temp controled long cool fermentation then d-rest may not be necessary BUT it wouldn't hurt to do one anyway.... I stand to be corrected but that's my reading of the info on here :)
 
OhCrap said:
From the information I've found here (yooper etc) if it's a cold pitch and a proper temp controled long cool fermentation then d-rest may not be necessary BUT it wouldn't hurt to do one anyway.... I stand to be corrected but that's my reading of the info on here :)
Click to expand...

Correct. One may not be needed but it also won't hurt anything either. Better safe than sorry before lagering.
 
OhCrap said:
From the information I've found here (yooper etc) if it's a cold pitch and a proper temp controled long cool fermentation then d-rest may not be necessary BUT it wouldn't hurt to do one anyway.... I stand to be corrected but that's my reading of the info on here :)
Click to expand...

Why would you dio it if it isn't necessary?
 
Denny said:
Why would you dio it if it isn't necessary?
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As I said I stand corrected BUT it wouldn't hurt, better to be safe than sorry. Wouldn't you prefer to do a drest for 2/3 days before lagering than to find out in 6/7 weeks that you should have done it?
 
OhCrap said:
As I said I stand corrected BUT it wouldn't hurt, better to be safe than sorry
Click to expand...

If you don't taste diacetyl in the beer, you simply do not need to do a d rest. "Better safe than siorry" is a good theory if you have a question about it, but if there's no diacetyl, why bother?
 
Denny said:
If you don't taste diacetyl in the beer, you simply do not need to do a d rest. "Better safe than siorry" is a good theory if you have a question about it, but if there's no diacetyl, why bother?
Click to expand...

I agree but does it not get more pronounced over time? Also for someone who dosent know what diacetyl is then For the sake of raising the temp for a couple of days I'd do it..... Different horses for different courses. Thee are people who will argue that either option is better...
 
Denny said:
If you don't taste diacetyl in the beer, you simply do not need to do a d rest. "Better safe than siorry" is a good theory if you have a question about it, but if there's no diacetyl, why bother?
Click to expand...

Here is a response from yooper to a similar thread asking why.
Yooper said:
Because some people can't taste diacetyl, and sometimes it's very hard to detect in small amounts. But it gets worse with lagering, so a very mild "slick" mouthfeel might be a butter bomb after lagering!
Click to expand...
 
OhCrap said:
I agree but does it not get more pronounced over time? Also for someone who dosent know what diacetyl is then For the sake of raising the temp for a couple of days I'd do it..... Different horses for different courses. Thee are people who will argue that either option is better...
Click to expand...

If it gets more pronounced, it's due to an infection and there's nothing you can do about it. If you don't taste diacetyl near the end of fermentation, when you'd do the rest, there is none due to fermentation issues and a rest isn't necessary. I used to do a d rest as a matter of course, but I stopped when I realized I was wasting time and effort.
 
Denny said:
"Better safe than siorry" is a good theory if you have a question about it
Click to expand...

Each to their own.....but if it's his first lager and isn't sure what to do then tell when a d-rest should be done (as per his q) and let him decide what to do after that. It's better to see 2 sides of a discussion and make a decision then.
 
Yes, it certainly is. I must have missed that it's his first lager. Sure, what the heck, do the d rest. Like an iodine test, it's good to do it once or twince before you decide you likely never need to do it again.
 
I actually bring all my beers up to room temp for a week to aid in attenuation. Sometimes its needed, sometimes not. It's a habit now, or I guess laziness because I won't take the 5 minutes to take a gravity reading.
 
dale1038 said:
I actually bring all my beers up to room temp for a week to aid in attenuation. Sometimes its needed, sometimes not. It's a habit now, or I guess laziness because I won't take the 5 minutes to take a gravity reading.
Click to expand...

Hah I hear ya man and I appreciate your input, well here goes nothing. I'm going for the d rest. Even if it is not completely necessary I believe it will help with an off favors I may have incurred by pitching the lager yeast warm.
 
the diacetyl rest also works for other off flavor? is my light lager with a flavor reminiscent of chlorine. do d rest can help?
 
marcelo said:
the diacetyl rest also works for other off flavor? is my light lager with a flavor reminiscent of chlorine. do d rest can help?
Click to expand...

No, for a chlorine flavor a diacetyl rest won't improve that. All a diacetyl rest is raising the temperature of the fermentation slightly. That's it. It encourages the yeast to keep working and after fermentables are gone they will actually go back and digest their own waste products (like diacetyl).

When you say reminiscent of chlorine, in what way do you mean? "Swimming pool", or like chlorospectic? Or something else?
 
is very difficult to describe the aroma and flavor that I feel this beer, and it's the third time it happens to me. initially seems like something fermented sugar cane, but soon reveals itself to more chlorine or cleaning product. and whenever it happened, was with ligh beers, lager or ale type.
never notice that in dark beers
 
marcelo said:
is very difficult to describe the aroma and flavor that I feel this beer, and it's the third time it happens to me. initially seems like something fermented sugar cane, but soon reveals itself to more chlorine or cleaning product. and whenever it happened, was with ligh beers, lager or ale type.
never notice that in dark beers
Click to expand...

With that description, I wonder first about fermentation temperature, and the temperature of the wort when the yeast was pitched. A high fermentation temperature can cause those "fermented sugar cane" flavors and aromas (fusel alcohols). Also, any stressed yeast can produce that flavor. If the yeast was underpitched, or stressed from other reasons, it could impact the beer greatly and cause some off-flavors.

The next thing I wonder about is the brewing water. What kind of water did you use for brewing?
 
right! I used the tap water filtered. inoculated yeast after two days, because I'm only doing no-chill brewing, and BIB. but what you said hit me in the face! because I increased all my recipe, minus yeast. I did as I always did to 19L bach. 1L of a starter for a package of dry yeast two days before. this was probably my mistake at this time as the temperature is still 12C. can i do something to eliminate this off flavor? or perhaps hide it by adding a few liters of wort made ​​of caramel malts, special B or chocolate, and other kind of yeast. because I just used pilsen malt and carapilsen for this recipe and got OG 1.044.
any help will be appreciated, because I do not want to throw away another 45 liters of beer
 
marcelo said:
right! I used the tap water filtered. inoculated yeast after two days, because I'm only doing no-chill brewing, and BIB. but what you said hit me in the face! because I increased all my recipe, minus yeast. I did as I always did to 19L bach. 1L of a starter for a package of dry yeast two days before. this was probably my mistake at this time as the temperature is still 12C. can i do something to eliminate this off flavor? or perhaps hide it by adding a few liters of wort made ​​of caramel malts, special B or chocolate, and other kind of yeast. because I just used pilsen malt and carapilsen for this recipe and got OG 1.044.
any help will be appreciated, because I do not want to throw away another 45 liters of beer
Click to expand...

I don't think the off-flavor will go away, but it may improve with lagering.
 
Yooper, about the idea of trying to cover up the off flavor with stronger flavor malt? could it work?
 
marcelo said:
Yooper, about the idea of trying to cover up the off flavor with stronger flavor malt? could it work?
Click to expand...

Have you decided what the off flavor is? If it is indeed from chlorine I doubt you will cover it up. If it is a yeast byproduct it may clean up during aging/lagering. Another possible option if it is yeast derived is to add more wort and fresh, active yeast. That could help clean up what was left behind.
 
I'm sure that is an off flavor from fermentation. To try to better describe what it is, just take another sample from the fermenter. since last night adjusted the thermostat to 18C D to try to make a rest, and now the smell has changed a bit, now it seems pineapple, chewing gum and hard alcohol, like vodka cheap. (and a bit of paint thinner behind all this) I'm beginning to think that the time will be enough. I'll wait the 3 days of the "D rest" to see what else can change around here.
 

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