My First Lager - When to Start Diacetyl Rest?

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cfiles

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I brewed my first lager (a simple marzen) 8 days ago. I have read about the diacetyl rest and how to do it. My question is when do I need to start it? Right now I still have a very active fermentation with a nice krausen but I am nearing the point where I need to start the rest (at least according to the instructions; it suggest 7-10 days after brewing).

Do I need to wait for the krausen to fall, or do I need to start the rest soon? Thanks!
 
Ideally you would do the diacetyl rest when fermentation is about 75% complete (using hydrometer, compare OG to anticipated FG). I'm not that anal though and just give mine a flat 10 days fermenting (remember that lagers usually take much longer to ferment than ales). Then raise to room temp (66-72) for a few days for the diacetyl rest. Then I transfer to secondary and drop the temp 5 degrees per day until I'm at lagering temp... I leave it at lagering temp 35-42 days.
 
Thanks for the information! Just waiting for 10 days, or for fermentation to all but stop, was what I was thinking, but I did not want to ruin the beer. It is good to hear that I was on the right path.

When you raise the temperature do you do it all at once or gradually? Right now my fermenter temperature reads 52-53.
 
I just let it raise naturally. I just take it out of the fermentation chamber and set it in a room that is at 66-72. I don't worry about raising it gradually.
 
10 Days sounds like a fine rule of thumb if you aren't keen on taking a lot of samples.

Also, I'm no lager expert, but I believe that if you do a proper diacytl rest, then you don't necessarily need to do the "slow crash" (couple of degrees a day). You can just cold crash straight down to lagering temps. The slow crash was used to not shock the yeast because the beers were traditionally lagered for a while, then warmed up and krausened to remove diacytl. If you've done a proper d-rest at the end of primary, you have no more need for the yeast (assuming you are kegging) and can crash them down to 32F as quick as you like.

Caveat: that's some Internet learnin' I dun, I'm not an expert.
 
I just looked at mine(i have glass) to see when it was tapering (about a week)i then raised it to room temp about 68 for 2 days then racked and lagered 15 degrees lower than its ferm temp for 3 weeks,worked out good except i used the temp difference for priming which had me use less which was a mistake. Now i think i have undercarbed lagers, so just use your normal amount of priming sugar and dont pay attention to those temp differences on brewing calcs.Im going on week 3 of priming and going to wait one more to check on carbonation.I then may reopen and add priming sugar-theres no way im drinking a flat lager. I just hope opening them at that point warm wont cause them to gush,if they do ill just leave them i guess.Probably a few more weeks then just refrigerate them.


Actually after i wrote this i kwick chilled one of my lagers at about 3 weeks, i poured it into a SS lager glass with etching and it is carbed and a beautiful lager good head and foamy lacing clear crisp and super tatstey! sucess one of my best so far and my first lager,definatly may post the recipe. I guess i was wrong about the temp carbonation factor.Another impatient noob error on my first lager.
I guess i should know better than thinking how sweet a 1.01 lager was after a week or two of bottle conditioning, guess i was paranoid it wouldnt carb up with such a low priming rate.Time,and time again...
 
Also, I'm no lager expert, but I believe that if you do a proper diacytl rest, then you don't necessarily need to do the "slow crash" (couple of degrees a day). You can just cold crash straight down to lagering temps. The slow crash was used to not shock the yeast because the beers were traditionally lagered for a while, then warmed up and krausened to remove diacytl. If you've done a proper d-rest at the end of primary, you have no more need for the yeast (assuming you are kegging) and can crash them down to 32F as quick as you like.

Caveat: that's some Internet learnin' I dun, I'm not an expert.

Interesting theory... seems plausible... I would be curious to read more. Got some links to share?
 
Thanks for all the info guys. I raised the temperature in my cooler to 70 for ~40 hours. Then I transfered to a secondary. It has been in the cooler, set at 40, for a week now. I plan on leaving in there for at least two more weeks before kegging.
 
Thanks for all the info guys. I raised the temperature in my cooler to 70 for ~40 hours. Then I transfered to a secondary. It has been in the cooler, set at 40, for a week now. I plan on leaving in there for at least two more weeks before kegging.

You don't have to let it sit in secondary at 40 degrees. I'd probably keg it and lower the temperature if you can. I like to lager at 34 degrees, for a longer period of time. I think it makes a much smoother lager than a lager kept at 40 degrees.
 
Ideally you would do the diacetyl rest when fermentation is about 75% complete (using hydrometer, compare OG to anticipated FG).

Not being a math wizz would I be correct in calculating a diacetyl trigger at 1.030 for an OG of 1.060 and expected FG of 1.020?
 
A question;
My work schedule is two weeks away two weeks home. Curious.... everyone talks of the primary ferment being somewhere in the neighborhood of 10 days give or take possibly depending on the gravity reading.
Best case scenario my Lager (when I start doing them) will be sitting in the primary for a minimum of 14 days before I can start raising the temp for the diacetyl rest.
Any thoughts on what will be the down side to having the gravity of the beer being lower than it possibly should be before I start the diacetyl rest? Am I going to make some sort of skunk?
Perhaps I should train my wife on the temp control of the freezer?
Any thoughts are appreciated! Thanks
 
Doing my first lager now and have conflicting info. Fermed mine for 10 days krausen dropped did a 4 day D rest. When I racked it took a gravity reading it had reached FG but had a butter flavor? I'm now leaving the racked beer at room temp for a week to try a cure the remaining "D". Since it's off the yeast worried about my results. I've seen no activity!
 
Doing my first lager now and have conflicting info. Fermed mine for 10 days krausen dropped did a 4 day D rest. When I racked it took a gravity reading it had reached FG but had a butter flavor? I'm now leaving the racked beer at room temp for a week to try a cure the remaining "D". Since it's off the yeast worried about my results. I've seen no activity!

It'll have a hard time cleaning up the diacetyl after racking, but it's worth a try! It'll get worse, not better, with lagering so you want to get rid of it now!
 
This thread seems like the right place for my question. I brewed my first lager a week ago, pitched a crapload of yeast and the beer has been fermenting at 50F for a week now. I took my first sample this evening and the gravity is already down to 1.011 ... I think I should be happy but I'm worried I missed the opportunity for a proper diacytel rest. My plan is to raise the temp up to 65F or so for the next two days and then slowly cool back to about 38F or so. Does that seem like a good plan to those of you with lager experience?
 
Yeah, depending on other factors you might not even have it to begin with. Taste it now and raise to 65f ASAP. If you have diacytl after the rest, get a starter going with any kind of yeast you have on hand, and pitch that into the beer when the new starter is at big krausen.
 
Thanks for the replies! I have the temp now at 65, and I actually have a starter going with harvested pacman that I was going to use for another brew, but could be re-purposed if needed.

On another note, I wasn't expecting to have such high attenuation so quickly given the lower temperature. Is this common? I pitched a big, healthy starter that correlated to Mr. Malty's calculator, but unfortunately I didn't cool the wort to fermentation temps before pitching. Does this cause the fermentation to accelerate?
 
Thanks for the replies! I have the temp now at 65, and I actually have a starter going with harvested pacman that I was going to use for another brew, but could be re-purposed if needed.

On another note, I wasn't expecting to have such high attenuation so quickly given the lower temperature. Is this common? I pitched a big, healthy starter that correlated to Mr. Malty's calculator, but unfortunately I didn't cool the wort to fermentation temps before pitching. Does this cause the fermentation to accelerate?

Absolutely. Just like pitching an ale at 90 degrees (twenty degrees too warm), pitching a lager at 70 degrees will make the yeast work harder and faster. Combined with a big starter, much of the fermentation would be over before the beer even gets to 50 degrees as it takes a lot longer for 5 gallons of fermenting beer to cool.

Make sure you do the diacetyl rest and hope that you don't have many side effects (like esters) from pitching too warm. Next lager, make sure you have temperature control at the beginning so this doesn't happen again.
 
Thanks Yooper. That makes sense and good advice for the next lager. On this one, the temp was down to 50 within only a few hours so hopefully the temp change was fast enough to avoid the side effects you mention.
 
If it was at 50f within a few hours, then you are probably OK. Try to get it down to your exact temp if possible before pitching, but a lot of later brewers pitch warm and get the temp down within a short time. I do No Chill for all my lagers, which has the advantage of being able to get he wort down to the exact temp I need before pitching.

And yeah, despite reading about 3 week primaries, all my lagers (six maybe) have finished primary fermentation within normal time ranges for ales. I was pretty surprised by this, but I think its just a sign of proper pitching rates and good fermentability. And I ferment in a fridge at exactly 52F.
 
My lager has been in diacetyl rest for 3 days now, with the gravity moving from 1.010 at the start to 1.005 currently. Tonight I took a sample and ran a diacetyl test as described in "yeast." I'm no diacetyl connessuier but I do detect an off aroma and taste that is slightly sweet and upfront, which I suppose could be described as buttery. I would have thought the diacetyl would have been cleaned up by now, so my question is this: is there any risk of extending the diacetyl rest past 2 or 3 days?

On another note, I'm also concerned about DMS as I may not have boiled my pilsner malt long enough. Could this be confused with diacetyl?
 
Just a quick look at the HBT wiki on lagering yielded some interesting charts:

https://www.homebrewtalk.com/wiki/index.php/Fermenting_Lagers

Lager_fermentation_charts.gif


These are all graphs of different lager fermentation schedules, and the effect that different temperature regimens have on diacetyl concentration.

Although the article seems to suggest that the (C) and (D) regimens are better suited for homebrewers, from what I've come across in the forums, the majority of people are using a diacetyl rest, illustrated in (F).

It's interesting to note that all 6 of these regimens appear to result in reduction of diacetyl to about the same level. It's also worth noting that in the examples where temperature is increased briefly (as in a diacetyl rest), once the diacetyl has been sufficiently reduced, there is no need for a gradual cooling of temperature - you can "crash cool" to lagering temperatures without having to worry about shocking the yeast, since they've already done their job.

A number of people have touched on these points, but for me, it was nice to see in a graphical format.
 
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