Pilsner fermentation problems

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sniklac84

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Hey guys, I'm new to this site, but so far i like the amount of info it provides.
So I brewed a all grain pilsner urquell last Monday. It's only my third all grain batch, but I felt up for a lager. I followed the instructions accordingly and used the pilsner lager white lab yeast(did not use a starter, I just followed instructions on yeast bottle)

My problem is that after almost a full week of fermenting I see no signs in my air lock. I started fermentation at 70 degrees like it said on my kit instructions, but got no signs of life but maybe a few islands of krausen. I then read that lagers like colder temps so I moved it down to the basement at 55 degrees. Still no activity in my airlock when I checked this afternoon, but it now has a very nice layer of krausen going on.

Is there anything I can do? Should I just let it keep fermenting for longer and hope it turns out or am I screwed?
 
First, you seriously under-pitched this. Did you do anything to aerate/oxygenate the wort before pitching? If not, that really compounded the problem.

Lager yeast is not just a different strain, it's a whole different species than ale yeast. Lagers need twice the pitch rate (1.50) vs. ales (0.75). That means big yeast starters. A 1.050 lager should get around 350 billion cells. Your one vial of yeast, even if it were just a month old only had about 78 billion cells.

That's why your ferment has been unusually slow in getting started. You only pitched about 20-30% of the yeast cells it needed. You may want to check the gravity to make sure that it hasn't already gone ahead and somehow fermented. How long did you have it at the higher temp?

That whole risky practice of starting a lager ferment warm is an attempt to make up for underpitching by using the whole batch to do what you should have done in starter wort which is multiply cells. It invites flavor problems. If your pitch rate is good, you can chill the wort to 45*F, pitch and let it ferment around 48-50*F which will tend to give you a nice, clean lager ferment.
 
lager yeast works at a lower temperature and takes longer. just leave it at 55 for a couple weeks then bring it back up stairs for 24 hours then lager it as cold as possible for 4-6 weeks.
 
It's hard to say exactly how well it's doing just based on airlock and kraeusen activity. Fermenting a lager at low temperatures means (this is what I remember Jamil saying in some podcast) more of the co2 gas will dissolve into the solution, and it will ferment slower than what you're used to seeing with an ale yeast.
 
That's great info on temp control, it makes total sense! I will always use a starter now. I just wish that the kit instructions or even yeast instructions would emphasize that a bit more.

I tried aerating it by rolling my fermenter back and forth .
It fermented at 70 degrees for two days before I brought it down stairs. I checked the gravity level at the second day and it hadn't changed.

So did by pitching 20/30% of the cells I needed just drastically slow down the fermentation rate? Does that mean it is going just take longer or that only 20/30% of the cells are being used and the rest won't work?
 
That's great info on temp control, it makes total sense! I will always use a starter now. I just wish that the kit instructions or even yeast instructions would emphasize that a bit more.

Don't feel bad. You're certainly not the first, nor will you be the last, newer brewer that's been given bad or incomplete advice via kit instructions. Some of them are pretty awful.


I tried aerating it by rolling my fermenter back and forth . It fermented at 70 degrees for two days before I brought it down stairs. I checked the gravity level at the second day and it hadn't changed.

So did by pitching 20/30% of the cells I needed just drastically slow down the fermentation rate? Does that mean it is going just take longer or that only 20/30% of the cells are being used and the rest won't work?

The reason you have to aerate/oxygenate wort is that the boiling drives most of the dissolved O2 out of solution. Yeast need O2 at the beginning (aerobic) part of the process in order to spawn new yeast cells before they switch over into anaerobic fermentation and make alcohol+CO2.

When you use liquid yeast, you have to re-introduce O2 into the wort or the cell reproduction will be diminished. It's especially important with lager wort due to the higher cell requirement. Rolling the fermenter back and forth won't get the needed O2 into solution for a lager. Many folks (particularly those who do lagers) either use an aquarium pump to bubble air into the wort via a stainless stone or bubble (also with a SS stone) pure O2 out of a tank.

When doing a batch (ale or lager) with dry yeast, aeration isn't as crucial since they come packaged with sterols that provide the O2 needed to get them through the initial aerobic/reproductive phase.

Pitching only 20-30% of the recommended # of cells into poorly oxygenated wort means that you now lack enough cells in the fermenter to grow a good colony that can properly do the job of eating the sugars. That can cause the issues you're seeing now like extended lag and might lead to a failure to attenuate (aka, "stuck fermentation"). At this point, you can either let it go and see what happens or pitch a couple packets of dry lager yeast on it. I'd suggest getting a gravity reading before you decide.
 
OK, I did a gravity reading at the 8th day of fermenting and it's down from 1.050 to 1.032 and it also has a very thick krausen going. So it's looks like it is fermenting slowly but surely. I just don't get why I have seen not one sign of activity in my air lock.
 
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