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Last weekend 2 of my friends and me tried brewing a lager (doppelbock) for the first time. Brewing went well, but not the yeast!

We are now 4 days later, and no sign of activity. Gravity taken: did not go down at all.

What are the solutions considering that we don't have access to another lager yeast vial easily (2 hours drive) ?

Can we buy an ale yeast and do it that way instead? What will be the results?

What are the other alternatives, if any?

Thanks!

EDIT:

It worked! It took almost one week but now we're getting something! :)

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which yeast and how much did you pitch? –  mdma Feb 13 at 12:35
    
If it took a week to get to this point, I would be very concerned about infection. When you go to do your diacetyl rest, check for a pellicle. If there's no pellicle, draw a sample before you drop the temperature to taste for any off flavors. –  Scott Feb 20 at 5:48

3 Answers 3

up vote 4 down vote accepted

It sounds like you underpitched by quite a large amount. As for options, you have some:

  1. Pitch an ale yeast. You'll want to bring the temperature up to at least 17 C to keep the yeast happy. You'll end up with an ale, not a lager, but still a good beer.
  2. Raise the temperature for a short while. If you can bring the temperature up to 15 C, you should start to see activity within a day or two. Once you see activity (krausen, bubbles in the airlock, etc.), slowly bring the temperature back down to 10 C. If you drop the temperature too quickly, the yeast will crash and drop out of suspension. A degree or two per day is what you're aiming for. The beer may taste slightly fruitier than one fermented at a lower temperature, but will still be a lager.
  3. Wait some more. If your sanitation was top-notch, the beer should be fine sitting for another few days. This will give the yeast a chance to reproduce, and start fermenting. If your sanitation was not so good, you may end up with an infected wort that you end up throwing out.

Those are your options, as a I see them. If it were me, I would go with 3 first. Wait for a few days. If nothing happens after 3 or 4 days, I'd probably just pitch an ale yeast and hope for the best. The problem with warming the wort without adding an new batch of yeast, is that there's a chance the yeast you pitched was just not viable. If that's the case, no amount of aeration or warming is going to get it working. You're better off cutting your losses and turning your lager into an ale.

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If it was me, I'd go with option #1 and pitch at least 2 tubes/packets of the cleanest Ale yeast you can get (American, Scottish, etc), just to make sure. Everything else risks ruining the beer. –  Graham Feb 13 at 15:20
    
So finally, option 3 was the good one! But thanks for the complete answer :) –  Simon Lapointe Feb 20 at 2:14

Primary lager fermentation should take ~2 weeks at normal fermentation temps (50-55°F), usually followed by a diacetyl rest.

If you only pitched one vial, it might take at least two weeks, since the first week is probably just growing the yeast population to ferment the batch. (If you split the vial between the 3 of you, may god have mercy on your souls.)

What was the original gravity? Did you pitch a single vial of yeast each, or split one? I'm assuming a starter was not made? At what temp is it fermenting? Did you do any oxygenation/aeration?

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OG was .066, it still is. That is a 23 liters batch, so we used one vial of yeast for it. You're right about the starter: we did not make one. It is currently fermenting at 9-10 Celcius. Yeah we did aerate it a lot! –  Simon Lapointe Feb 13 at 4:16
1  
(I realized on reflection that the 3 of you brewed one batch, not that you split the batch into 3rds.) Regardless, commercial lager pitching rates are like 3-5× what you actually pitched, so it's going to take a while for the yeast to catch up. On my batch the other week, with a well-starter'd lager yeast culture, I didn't see activity until the 3rd day; I expect it will take another couple of days for you at least. Patience alone I can recommend. No need for ale yeast or anything. –  jsled Feb 13 at 4:44

I'm new to the site so I can't comment on other posts? otherwise I would have added this to Tobias Patton's post which is spot on. My only addition would be for next time. I would recommend using a yeast starter, especially with high OG brews. I have found this technique to be well worth the investment (time).

What was your OG? Keep in mind high OG brews benefit from using larger yeast colonies to kick start fermentation (otherwise you have to wait for the same effect in the main batch, see Tobias answer #3). I started using this technique for brewing big IPAs and have not had trouble with the onset of fermentation since. It's pretty straight forward and quite satisfying to have a vigorous fermentation in hours instead of a day or so...

Good luck!

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