have i screwed up the diacetyl rest

[Sarrsipius]

I'm doing my first lager and I am following the directions of the LHB shop guy. He said that once fementation is 75% complete, raise the temp to 70deg and hold it there for 3 days...then rack to secondary and reduce temp by 3deg per day down to 35 and lager at 35deg for 60 days.

After 7 days at 49deg I took a SG reading and it was 1.020 which is what I calculated it would be at 75% complete. There was still a lot of airlock activity (about 1 bubble every 2 seconds) but I did as instructed and brought it up to 70 deg. That was 24 hours ago. There is still a lot of airlock activity.

I did a search on HBT and found most people recomend waiting until visible fermentation is complete and then doing only a 24-48 hour diacetyl rest before racking to secondary and lagering.

Have I made a mistake? Should I cool it back down to 49 and wait until airlock activity stops and then do another diacetyl rest? Or should I just let it finish fermenting at 70 deg and then rack it to the secondary?

 

[Yooper]

Leave it out. There will be lots of airlock activity because it's still fementing, as well as having the warm temperature cause the trapped co2 to come out of solution. Don't worry about it!

Wait until the FG is reached before racking, though. So, now that you're doing the rest, don't rack to secondary until it's completely done fermenting and the SG is no longer dropping. Then you can rack to secondary and begin lowering the temperature for lagering.

 

[Sarrsipius]

Ok. I can handle that. I expect it will be close to my estimated FG tomorrow night. I think I will rack it then and start slowly cooling it. I've read several articles tonight that suggest doing the rest after racking to secondary to avoid the yeast cake lending off flavors. Sounds like either way would work...I'll split the difference and rack it tomorrow regardless of the gravity and let it finish fermenting in the secondary. Thanks for the advice and any other opinions are welcome (I know there are no shortage!!)

 

[Yooper]

Ok. I can handle that. I expect it will be close to my estimated FG tomorrow night. I think I will rack it then and start slowly cooling it. I've read several articles tonight that suggest doing the rest after racking to secondary to avoid the yeast cake lending off flavors. Sounds like either way would work...I'll split the difference and rack it tomorrow regardless of the gravity and let it finish fermenting in the secondary. Thanks for the advice and any other opinions are welcome (I know there are no shortage!!)

No, I don't think you want to do that. You want to do the diacetyl rest ON the yeast cake. It's the yeast themselves that do the work of digesting the diacetyl, so racking it before it's at FG could cause some diacetyl issues, as well as stall the beer if it's not at FG.

I don't know what the several articles you've read that tell you to do that in a lager, but I wouldn't go by that. In an ale, yes. But not in a lager during a diacetyl rest. I think to rack it before the diacetyl rest is finished and before it reaches FG would be a mistake.

 

[Sarrsipius]

Got it. I haven't been steered wrong yet by HBT and you sound like you speak from experience so I'll go with that. I'll wait for it to reach FG and then rack it.

thanks again.

 

[Yooper]

To make it even more interesting, sometimes lagers don't even need a diacetyl rest.

Some strains are notorious for producing tons of it, while some strains don't produce much. Also, if someone cold pitches a large starter, it seems like the formation of diacetyl is halted a bit and so the beer doesn't have much diacetyl to begin with and it'll get cleaned up in the primary.

I've had about 1/2 of my lagers not even need a diacetyl rest. However, if you're not experienced in detecting diacetyl, even in very small amounts, it's safer to just always do a diacetyl rest. No harm will come to the beer, since the vast majority of fermentation is finished, so many brewers just do it routinely.

Since the lagering is long term, it's really nice to rack after fermention is over so you're not aging on too much yeast. You'll still have a small yeast cake in the secondary after the lagering period, but you shouldn't have a risk of autolysis.

Just thought I'd throw those asides in there! Lagers are fun, and worth the pampering in the end. I'm drinking a Vienna lager right now (literally, right now) and it's so satisfying! It was a double decoction, a huge (6 liter!) starter, a cool ferment, and 9 weeks of lagering. It's not my favorite style, but it's a beer that I'm very proud of because of all the work.

 

[Sarrsipius]

I don't think lagers will be my go to style but I couldn't wait to try one. I've done about 15 ales so I'm not very experienced but I've had 15 great batches of beer and wanted to check out something a little more complicated. Who knows, in a couple months when I taste this lager I may be a convert!

 

[Yooper]

I don't think lagers will be my go to style but I couldn't wait to try one. I've done about 15 ales so I'm not very experienced but I've had 15 great batches of beer and wanted to check out something a little more complicated. Who knows, in a couple months when I taste this lager I may be a convert!

It's fun just to have another recipe in your arsenal! I don't make many lagers any more, but I make at least a couple of traditional ones every year- like an Oktoberfest, and a Maibock for fall and spring, and then an occasional other lager like Vienna lager, on tap now. If you like big bocks, like a dopplebock, there are some great recipes out there for them.

 

[Sarrsipius]

So it's been 72 hours since I brought the temp up to 70 degrees. I still have active fermentation (about 1 bubble every 6 seconds). I'm concerned that if I wait longer that the high temp may start to become an issue. As I see it I have 3 choices

1. Wait until primary fermentation is complete (leaving the wort at 70deg) and then rack to secondary for lagering.
2. Rack to secondary tonight and allow fermentation to finish during the lagering.
3. begin cooling the wort in the primary and then rack to secondary (at lagering temps) once fermentation is complete.

Is leaving it at 70deg for a 4th day bad? That would be my first choice if it's ok. What should I do?

 

[Yooper]

What's the SG over this time? If it's dropping, leave it be. If the SG is stable (not changing), it's fine to rack.

 

[Sarrsipius]

I haven't checked it since Sunday (since there is still visible fermentation activity I am fairly certain it hasn't finished yet).

Will I need to be concerned about the higher temp at any point?

 

[Yooper]

I haven't checked it since Sunday (since there is still visible fermentation activity I am fairly certain it hasn't finished yet).

Will I need to be concerned about the higher temp at any point?

Not really. The vast majority of fermentation was over, if you did the diacetyl rest at 1.020.