Lager Fermentation

Good Morning brewers,

I have spent a lot of this last year trying to perfect my lager techniques and occasionally run into a stuck fermentation that I keep trying to troubleshoot when it occurs. Last weekend I made two lagers, a czech pils and a schwarzbier using WL800 and WL830. The OGs are 1.060 and 1.055. I pitched two packs of each yeast into each 5 gallon batch since I didn’t have time to makes a starter. I know this is still a low pitch rate but it should and has worked for me in the past. I pitched at 50 degrees F and saw no change in gravity 3 days. Bumped the temperature up to 60 now slowly over a week and have seen a few points start ticking away, but not at the rate that I am used to seeing for lagers. What should I do to try to accelerate these fermentations now and in the future? I have previously tried pitching more yeast at up to 62 degrees but got overwhelming esters (as one may expect for a lager yeast at that temp) and do not want to risk that again. I also have tried shaking the yeast back up after it has been warmed up a bit and am waiting to see if that helped.

Any help is appreciated.

What is your reason for wanting to accelerate fermentation? I find lag times to be longer with lagers  in general.

I want to ensure that there won’t be a problem with the fermentation. Previously I had it stall at around 25% attenuation on a regular OG beer with a starter which worries me.

What was the date of manufacture for the yeast? I use both of those yeasts and pitch 4 packs into 15 gallons @ 50*. Thats not to far off of your rate. Lag time is roughly 18 hours. Make sure to aerate/oxygenate.

I agree with HopDen - the age of the yeast coupled with a lack of sufficient oxygen can be causing an issue.  Further, have you had the same issue with ales?  My thoughts are possibly a water issue and/or the lack of yeast nutrients.

I have been pitching all of my lagers at 60 to 64 F with no esters detectable. Note however that I have been using 34/70 or Imperial Harvest which are both known for being able to tolerate warmer temps.

Did you try more yeast at more traditional lager temperature (pitch < 50)?  That should prevent ester formation if you experienced that before. Or, maybe try your warm pitching with more o2.  Pure O2 will get you there better than air.

I never do lagers without a large starter and aeration with pure O2.  I know time can sometimes be a scarce commodity, but you asked what could speed up your ferment in the future.  Pitching a starter at high krausen should get things going relatively quickly.  A small investment in starter time is far less than waiting 5 days for ferment to begin.

I have had slow fermentations in the past but recently began to pitch a large amount of yeast (some say overpitch).

I found the batches with more yeast started faster, finished faster, and finished lower (higher AA %) than those pitched at a lower rate which started sluggishly, plodded along, and finished high (low AA %).  My lagers are finishing in 5 - 6 days now though I do ferment at 60*F.

Even though you pitched two packs, without the starter to increase cell count you probably didn’t pitch enough yeast. The evidence is the sluggish behavior.

Thanks everyone. For the curious, the two batches have gone from 1.055 and 1.061 to 1.035 in a week, but they are still moving. I did not check the date on the yeast packs unfortunately but Adventures usually is on top of it. I used a aquarium pump aeration setup to aerate. I think the combination of underpitching and not adding any additional yeast nutrients are the main issues of concern. If anyone has some knowledge on this, would it be worth investing in a pure O2 system if I continue to brew lagers?

I think if you pitch liquid yeast you should oxygenate the wort.

I use the red disposable bottle of O2 with a diffusion stone when I oxygenate.

Does pitching a Shaken Not Stirred (SNS) starter at high Krausen also eliminate the need to oxygenate the wort? I thought I read that somewhere.

I might be wrong, but I believe the information you’re referring to is in regard to the starter itself.  In other words, the starter is fully oxygenated by shacking as opposed to using a stir plate where the circulation causes an ingestion of oxygen.

I don’t do any further aeration after pitching an SNS starter and have never had a problem because of it.