Author Topic: Lager yeast slow to act  (Read 1013 times)

Offline DaveR

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Lager yeast slow to act
« on: October 22, 2010, 11:31:40 AM »
After 8 batches of ales I decided to try a lager. I began a starter of WLP830 5 days prior to brew day. I made 1 liter of 1.040 wort (just over a half cup of DME in a liter). I used a pinch of White Labs yeast nutrient. I stepped up using a second liter after 48 hours. I cold crashed everything at 96 hours. The starter didn't look too active. I smelled it and there was a hint of butterscotch aroma. I figured something was going on (whether good or bad, I don't know)..

Twenty four hours after cold crash only the very top (about 1 inch) of the starter cleared. There appeared to be about 1/4 inch of yeast at the bottom of the flask. I'm new to this and still learning but it seems that a lot of yeast remained in suspension.

I used the Top Drop Pilser receipe from "Joy of Home Brewing" as my first lager recipe. The OG came out at 1.052. I cooled the wort to 62 degrees F and warmed the starter to just over 55 degrees F.  I pitched all the entire starter. I should have used glass but I used a plastic bucket. I set my kegerator/refrigerator to 48 degrees. The wort stabilized at 50 degrees F.

After 4 days there was still no activity in the airlock. I was getting worried. I searched the forum to weight my options. I was about to pitch some ale yeast and I noticed activity in the airlock. I'm happy to say that now on the 5th day fermentation is finally going strong (although not "ale" strong).

Is this type of delay abnormal?. The yeast was close to expiration, but not over. I don't know how well it had been stored since I bought it from LHBS just two weeks ago. I think if I had to do it over again I'd make a larger starter, like a gallon,  and I'd start it 8-10 days in advance. Or maybe I'll just stick with Ales (unless this batch turns out great! What should I hope for?).

Dave. 


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Re: Lager yeast slow to act
« Reply #1 on: October 22, 2010, 01:44:01 PM »
Quite simply, you underpitched. I know you think you pitched a lot of yeast but you didn't pitch enough for a lager. For a 1.050 lager you need to pitch the slurry from a one gallon starter - at the very least. Also, are you using a stir plate? If so that will get you closer. If not you were a good deal of.

I usually have krausen on my lagers in 24 hours, though have gone 48 hours many times without any ill effects. With a four day lag you may not have as clean a lager as you may want. Still porbbaly will be a drinkable beer though.

Next time check the pitching calc at www.mrmalty.com and make the right size starter for every beer every time.
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Offline a10t2

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Re: Lager yeast slow to act
« Reply #2 on: October 22, 2010, 01:45:27 PM »
Well, with a 1 L starter, even "stepped up", you pretty significantly under-pitched. Standard would be ~400 billion cells, and you would have had between 150 billion (still starter, with airlock) and 350 billion (stir plate, no airlock). So a long lag would be expected. On top of that, pitching warm and then cooling the beer can "shock" the yeast and further increase lag time. It's always best to pitch at or below fermentation temperature.

I'm sure this batch will turn out fine. Just make larger starters and pitch cooler in the future.
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Re: Lager yeast slow to act
« Reply #3 on: October 22, 2010, 02:43:52 PM »
Agreed - I wouldn't pitch a lager yeast warmer than 50 degrees.
Keith Y.
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Offline wingnut

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Re: Lager yeast slow to act
« Reply #4 on: October 22, 2010, 03:08:07 PM »
FYI with the 830 yeast, when it does get rolling, it will thorw off a lot of sulphur.  If you smell rotten eggs... That is actually a good thing! Do not be alarmed!  Also, if you are used to doing Ale yeast, you will find that the lager yeast never really gets going like an Ale yeast.  Ales tend to ferment "like sprinters", they go fast and finish quickly.  Lager yeasts tend to start slowly, ferment with less activity, and take longer to finish out.  (I usually allow the lager to ferement for two weeks vs one week for the ale).

In the end, I expect you will have a tasty beverage on hand, even with the longer lag time. 

One other thought, with the long lag time, and likely under pitch, you may wish to do a diacetal rest to let the yeast clean up their by products from multiplying so much.

Good luck!!
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Offline DaveR

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Re: Lager yeast slow to act
« Reply #5 on: October 22, 2010, 06:58:41 PM »
Thanks everyone for your great feedback. I was afraid that I may have under pitched. I'll give this batch plenty of time in the fermenter. I'll monitor gravity and do a diaceytl rest. When I do another lager I'll be sure and go big on the starter.

One great thing about home brewing is there's a lesson -- or two, or three -- in every batch. My brother-in-law got me started brewing earlier this year. Now I can't get enough of it. Again, I really appreciate the wealth of knowledge on the forum.

Dave 

Offline bluesman

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Re: Lager yeast slow to act
« Reply #6 on: October 22, 2010, 07:57:23 PM »
Welcome to the AHA Forum Dave.

There's a yeast pitching rate calculator at mrmalty.com for future reference.
One of the most important parts of the brewing process is the fermentation stage.
Pitching an appropriate amount of healthy yeast and pitching low (temperature) is paramount to producing great beer.
For most lagers, I like to pitch in the upper forties and ferment at 50 degrees.

While you will make beer, there is always a learning lesson in every batch that is made.

Good Luck!
Ron Price

Offline troy@uk

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Re: Lager yeast slow to act
« Reply #7 on: October 23, 2010, 10:44:16 PM »
Welcome to the wonderful world of Lagers.  They do require an additional set of skills/knowledge and you are in the right place for information. 

You have a very important piece of equipment in the temp controlled kegerator!

We do a lot of work for our beers and then hand them over to the yeast to finish up. We need to give the yeast all the help we can for the job we expect them to perform.

Others have already mentioned the amount of yeast to pitch and you did mention that you gave the starter a bit of nutrition.  It is good insurance to also add nutriant to the wort during the boil. One important aspect that you didn't mention is airating the wort, I'm sure you did this because you are familiar with it from your ale brewing, but lager yeast really needs a lot of airation, there are many ways to do this, just remember to do more of it for your lagers.  Many books do say that lagers can be pitched @ 65*F and then lower the temp to 50*F.  The fine print with that method is to have the starter temp closer to the temp of the wort to prevent shocking the yeast and to keep the beer @ 65*F untill fermentation begins before SLOWLY lowering the temp to 50*F.  This method works, but as noted above, it is not the prefered method.  It is preferable to spend more time getting your wort cooled to fermantation temp before pitching a lot of healthy yeast into a nutriant rich, well airated wort.

Now , you may ask how I know all of this, it is because I did the exact same thing you did with my first Pilsner.  Mine had a 72+ hr lag time and I almost gave up and dumped it when it started to take off.  Bottom line is that the beer turned out fine and I couldn't wait to make another with more help for the yeast.
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