I set up a new fermentation chamber and was keen to try my hand at a lager. Unfortunately now 5 days on there hasn't been any fermentation so I think I may have shocked the yeast with the cold or just not given it enough of a headstart.

I'm brewing a Pilsner based on the how to brew recipe using White Labs WLP800 Pilsner lager yeast. Fermenting at 50F / 10C. I only left it in the starter for about 3 or 4 hours, and the temperature was probably about 15C but fluctuated a bit.

A couple of questions, what's the best way to proceed? What is the best way to do a lager starter in the first place?

  • According to Mr. Malty, you'll want to pitch more yeast than just one vial (2.6 vials or round to three). Go get another two or three vials from your LHBS. If they don't have any more of WLP800, get WLP830 or WLP840. This is assuming you're OG is 1.036 at a 5 gallon batch size as you described on your reddit post.
    – Scott
    Aug 25, 2014 at 13:44
  • So Colm ... what did you do and how did it turn out? Sep 17, 2014 at 9:23

2 Answers 2


Well, hard to chase an answer by D.C. but here you go:

  1. I like to count air bubbles in the airlock. Immediately after filling the carboy, you could have some off-gassing that isn't fermentation however (just like after transferring to secondary). No bubbles at all?

  2. Checking the gravity sounds good but bear in mind you should see some rapid changes in gravity. A tiny change in gravity isn't what you are looking for after 5 days.

  3. As D.C. says, you probably underpitched a lot. For best results in all home brewing, start your yeast at least overnight (or even 2 or 3 days before pitching). Here's a white labs guide to yeast starters: http://www.whitelabs.com/beer/homebrew/starter-tips

  4. You could consider chilling to only 60 F initially or allowing your wort and yeast a day of fermentation at a warmer temperature before moving it to a lower temperature. I have used this trick in my garage. Laundry room is closer to 60, garage closer to 50. First day in the laundry room, then move to the garage when fermentation is 'proofed'.

  5. What to do now: Check your gravity and observe the airlock. If no fermentation, then taste your beer. If it still taste all right and smells all right, I'd repitch with new yeast. If you have a few bucks to waste, buy two yeast packs. Throw one in right away and put the other through the starter. Pitch the starter into the beer in a couple of days if there is still no fermentation. Pitch half of it if there is ferm and use the other half of the starter on your next batch the following weekend (refrigerate the starter). If your beer tastes weird or sour and you like it, pitch new yeast as above. If it tastes weird or sour and you don't like it, dump the beer and brew again. Better that than to bottle garbage you toss later.

  • I can't stress enough that pitching lager yeast at 60 and letting it ferment at that temp is a really bad idea. Sure, you get a faster start but at the expense of beer flavor. It's just not necessary if you pitch a an adequately sized starter of healthy yeast. And you'll make MUCH better lagers like that.
    – Denny Conn
    Aug 25, 2014 at 15:38
  • Relax and have a home brew. But I suppose I should have specified that of course it matters what yeast you are using. I have done this successful with Oktoberfest, SF Lager, and Cry Havoc. I haven't tried it with a lower temp lager yeast. whitelabs.com/beer/homebrew/listings?style=4 Aug 26, 2014 at 7:15

A lager needs a really big starter. Somewhere on the order of a gal. starter is normal. That takes several days to build. You likely underpitched. In the future, use a resource like www.mrmalty.com to calculate your starter size. Are you certain there's no fermentation at all? Have you checked the gravity? That's really the only way to know. I would guess it is fermenting, although slowly.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.