Ok so this is the second german lager I made. The first one was an oktoberfest with an OG of 1.056
The beer fermented at 50f using WLP820 I made a 2 liter starter with 2 viles. It fermented in 11 days and then crashed to lager temps at 35f for a month. After one month I bottled half the batch and left the other half to continue to lager and still i had apples. I figured it needed more time so i continued to lager for another month. Still no difference. The bottles stayed at room temperature for a good 3 more months after that and the apples finally faded away. So i decided to take the other half that I kegged and brought it to room temp to perhaps clean up these flavors. After a month in the keg at 70f the beer cleared perfectly.
Now my current situtation is the same and i’d like to know what I am doing wrong. I have a munich dunkel lagering in the primary fermenter for almost 3 weeks now and it has a strong sour apple aroma and flavor again. Can someone tell me what i could do to prevent this or reduce it so it doesnt take 6 months to condition? I shouldnt be getting such strong Acetaldehyde issues. I dont airate i just shake the crap out of the carboy. Maybe there’s not enough O2 so the yeast are struggling? needs some expert lagerers to chime in here. Oh and the Munich Dunkel i made a 2 liter starter from one smack pack of munich lager yeast and then made a Gallon starter from that. the OG of the beer was 1.050 so i think i had plenty of yeast. Maybe i’m wrong? So I used 2 different yeasts with the same results. I am guessing its my process.
Common problem, and usually a sign of young beer. Also, you really shouldn’t crash to lager temps, you should decrease temp gradually. You don’t want to shock the yeast, the yeast is actually still working to clean up during the lager phase.
Yes i raised the temp from 50f to 60 slowly and held it for 3 days. then I brought it down to lagering temps. Should I bring it back up to maybe 70f? until the apples are gone?
According to Chris White & Jamil Zainasheff “Yeast” book the possible causes for acetaldehyde are: mineral deficiency, contamination by wild yeast or bacteria, under pitching, over pitching, High dissolved oxygen, incorrect fermentation temperature, vacillating fermentation temperature, and reused yeast that was collected too early. Obviously, that’s a long list. So its hard to say which one is your problem without knowing a lot more about your process.
In my experience (BTW, my Of’est won 3rd place at the NHC finals this year!) the main reasons for “apples” are under pitching and/or racking the beer away from the yeast cake too soon. According to my math, it sounds like you under pitched your first O’fest. Here’s why. According to Mr. Malty you need about 400 billion cells for a 1.050 lager. That is 4 “fresh” smack packs or the equivalent starter. If you made a 2 liter starter @ 1.040 and put 2 “fresh” smack packs into it you would only end up with 300 billion cells. Only 3/4 of the yeast you need. (See the table on pg 143 of the yeast book). OTH, 1 smack pack or vial in a 2 liter 1.040 starter will double your initial 100 billion to 200 billion. So what I do is put each smack pack into a separate 2l starter and end up with my 400 billion cells. If I need more yeast than that, I just make a 1.050 lager with the previous starter and then repitch from the slurry to the higher gravity beer.
As for your second beer with the stepped starter should have yielded 400 billion cells if the pack you started with was very fresh and if you put the decanted yeast into 4l of new starter vs. adding more starter to make 4l. It is still possible that you under pitched even if you used 4l of new starter if you used a pack that was more than a month old. Here’s the math, (again according to pg 143 of the yeast book.) 1 pack in 2l = 200B. 200B in 4l = 400B.
If you are serious about lagers, and it sounds like you are, the yeast book is a must read!
[quote=“Duxx”]According to Chris White & Jamil Zainasheff “Yeast” book the possible causes for acetaldehyde are: mineral deficiency, contamination by wild yeast or bacteria, under pitching, over pitching, High dissolved oxygen, incorrect fermentation temperature, vacillating fermentation temperature, and reused yeast that was collected too early. Obviously, that’s a long list. So its hard to say which one is your problem without knowing a lot more about your process.
In my experience (BTW, my Of’est won 3rd place at the NHC finals this year!) the main reasons for “apples” are under pitching and/or racking the beer away from the yeast cake too soon. According to my math, it sounds like you under pitched your first O’fest. Here’s why. According to Mr. Malty you need about 400 billion cells for a 1.050 lager. That is 4 “fresh” smack packs or the equivalent starter. If you made a 2 liter starter @ 1.040 and put 2 “fresh” smack packs into it you would only end up with 300 billion cells. Only 3/4 of the yeast you need. (See the table on pg 143 of the yeast book). OTH, 1 smack pack or vial in a 2 liter 1.040 starter will double your initial 100 billion to 200 billion. So what I do is put each smack pack into a separate 2l starter and end up with my 400 billion cells. If I need more yeast than that, I just make a 1.050 lager with the previous starter and then repitch from the slurry to the higher gravity beer.
As for your second beer with the stepped starter should have yielded 400 billion cells if the pack you started with was very fresh and if you put the decanted yeast into 4l of new starter vs. adding more starter to make 4l. It is still possible that you under pitched even if you used 4l of new starter if you used a pack that was more than a month old. Here’s the math, (again according to pg 143 of the yeast book.) 1 pack in 2l = 200B. 200B in 4l = 400B.
If you are serious about lagers, and it sounds like you are, the yeast book is a must read!
My second lager I decanted the 2L into a 4L and the smack pack was less than a month old yet I still have the problem. I didnt rack off the yeast cake so its still in the primary at 40f right now for about 3 weeks already. I highly doubt its an infection and there is no way I over oxgynated since I just shook the carboy which gives a max of 8ppm. I did a D-rest to 60f for 3 days after the 50f fermentation completed then crashed it to 40 all in the same carboy. Should I bring her back up to 60? for a few more days?
If it is not yeast numbers then I would look at your fermentation profile. Lager yeast works much slower than ale yeast. So how do you know when a lager fermentation is “finished?” Answer: When you have clean beer, not just when the specific gravity drops. It doesn’t sound like you let your yeast clean up the by products of fermentation before you took them out of the game. Lager yeast will work at low “icebox” temperatures but only if you get them there on a gentle gradient. “Crashing” the temps from 50 to 35 will slow them to a crawl and it will take months to clean up the “apples & butter.”
Here is a sure fire way to get a clean beer next time. Just use this fermentation profile, without any “modifications” on your next batch. Cool your wort to 44 or 45F. Pitch the correct amount of yeast (one vial in 2L starter X2 for a 1.050ish beer. Ferment the starters @ 50F covered with foil. Shake them up as often as you can. Let them go for 7 days then decant and pitch.) Oxygenate as you usually do. Put your temperature probe inside the fermentor (in a theromwell) set @ 49F with a +/- 1 degree range. Let the heat of fermentation bring your beer up to the 50 degree set point of your temperature controller. Leave the fermenting beer alone, in the primary fermentor, for 4 weeks @ 50F!!! Don’t test it, don’t open it, just leave to do its thing. “Set it and forget it” Don’t bother with a D-rest or any other temperature change. Then package and serve.
This will make a clean lager for sure. If you still have off flavors then you have to look at other “process” problems but you will at least know for sure it is not a pitching rate or fermentation profile problem.
Here’s my process, for what its worth. I haven’t entered any contests or won any awards but I feel like I make good beer.
Chill to upper 40’s before pitching yeast. I use a swamp cooler (in my already cool basement) to achieve and maintain fermentation temp.
Aerate well. If you’re just shaking you may not be getting there unless you really shake the snot out of it for a long time. Personally I use an aquarium pump and stone, and forget about it for a while while it cools and I do some cleanup. You might look into getting a mix stir, which does just as well and should be faster.
Pitch plenty of yeast. I make a 1 gallon starter for most 1.50ish lagers. If I need more than that I’ll often make a 1.040ish light lager first, and then use the yeast cake from that. Personally I make starters at room temp.
Ferment for a while, at least a week beyond when I “think” its done. 4 weeks is typical. 11 days is too short. Don’t get in a hurry.
Diacetyl rest: I just take it out of the swamp cooler and allow it to reach basement temperature (usually low sixties). Leave it there for roughly a week. Not all yeast necessarily requires a diacetyl rest, but personally I’ve always done one.
Rack to keg (or whatever your lagering vessel is), and gradually decrease temp to lagering range (mid 30’s for me). I do this in a chest freezer with temp controller. This is the same freezer I serve beer from, so during the initial cooldown I sacrifice and have warm-ish beer in my other keg. You can begin carbonating during this period. I try to leave it alone for at least a month, and its usually not at its best until several months of lagering (depends on the beer). Once its all carbed up though, I’ve been known to take a number of “samples” before I declare it “done”.
Yes i raised the temp from 50f to 60 slowly and held it for 3 days. then I brought it down to lagering temps. Should I bring it back up to maybe 70f? until the apples are gone?[/quote]
You can try, but I’m not sure how much yeast activity you will have left at this point. I don’t have a heck of a lot of lager experience, but 60F for 3 days sounds a little low/short.
My recommendation for a D-rest is to taste samples. When the diacetyl and acetaldehyde flavor is gone, then you can safely bring it down to lagering temp.
im proud to report that after 2 weeks in the keg at 75 the apples are almost gone!!. I transfered the whole batch to the keg making sure I picked up some yeast from the bottome. Every few days I gave her a shake to bring the yeast back into suspension and it looks like it cleaned itself up a lot quicker. Im going to bring it to lagering temps soon and let it sit for a few more weeks. Looks like the yeast were stressed out and didint finish cleaning up. thanks for all of your advise.
