First time lager question

[elgee]

I am making an American lager for the first time. I am using 2 packs of WLP840. Made a 1600 starter and decanted. Expiration date was 3/31, so close to the end of life? Anyway, after a week of fermenting at 52, it’s dropped from 1.056 to 1.040. Is this slower than usual? I’m worried the yeast was too old even with the starter? I know it takes more time than an ale, but seems like it’s started to slow. No more airlock action, not that it matters.

 

[brownni5]

While I don't have experience with that particular yeast, it does sound slow. But, expiration dates are loose guidelines and "close" to expired really isn't that close IMO.

Someone is going to ask - how are you measuring the gravity?

Someone is also going to ask whether you used a yeast starter calculator. OG of wort? How old was the yeast?

 

[okiedog]

elgee, if your starter fermented well, that's a good indication that the yeast should be healthy enough. However, a drop of only 16 gravity points indicates that the yeast has not done much work. A slow start is usually due to insufficient yeast cell count. How big is your batch-5 or 10 gal.? Two of the most important things I've learned about the fermentation process, are temperature control and patience. I would start moving the temp on up to 54-55F over the next 3 days, and hold there in primary through week 2. If this doesn't spur more airlock activity, then you need to add more yeast. Give it a chance though. I have had good brews fermented with WLP 840. I always rack my lagers to secondary (but not my ales), and allow a total of 3 weeks in the fermentor. Keep us posted on the status of this brew.

 

[McKnuckle]

Refractometer?

Use this calculator to account for the presence of alcohol. Otherwise the reading is no good. I'm starting to keep count of how many times I make this post (I think this is #4).

 

[jdauria]

Lagers are slower to get going then ales, but not that slow. 3/31 expiration date puts packaged date around 11/30, which puts yeast viability around 24% or 48 billion cells in the two packs combined instead of 200 billion if fresh. Using Brewer's Friend yeast calculator, a 1.056 lager needs, at their lowest lager rate, 392 billion cells. 1.6 liter starter (assuming 1.040 starter gravity and a stir plate) would = 304 billion cells, which is 88 billion short of target. So underpitching, plus colder temps would explain while it's very slowly moving. With lagers I would highly recommend using a yeast calculator and pitch accurate amounts.

 

[elgee]

Lagers are slower to get going then ales, but not that slow. 3/31 expiration date puts packaged date around 11/30, which puts yeast viability around 24% or 48 billion cells in the two packs combined instead of 200 billion if fresh. Using Brewer's Friend yeast calculator, a 1.056 lager needs, at their lowest lager rate, 392 billion cells. 1.6 liter starter (assuming 1.040 starter gravity and a stir plate) would = 304 billion cells, which is 88 billion short of target. So underpitching, plus colder temps would explain while it's very slowly moving. With lagers I would highly recommend using a yeast calculator and pitch accurate amounts.

Thanks, I’ll have to add more yeast. Perhaps a packet of dry yeast since there are more cells? I don’t know if a dry packet will throw off the taste since I used the liquid American lager yeast and I don’t think there is a similar dry type? I made 5 gallons, and the starter was at 1.040.

 

[jdauria]

Thanks, I’ll have to add more yeast. Perhaps a packet of dry yeast since there are more cells? I don’t know if a dry packet will throw off the taste since I used the liquid American lager yeast and I don’t think there is a similar dry type? I made 5 gallons, and the starter was at 1.040.

Sorry, have not been on the site for a week, a dry yeast pack should not change the flavor at this point.

 

[kevin58]

I would not add more yeast at this point. As someone else pointed out lagers ferment slower. If your yeast expiration date was 3/31 it is fine. Don't worry about it. Don't fiddle around trying to "fix" it. Just let it ride.

 

[McKnuckle]

A couple of us have asked if you're measuring gravity with a refractometer or a hydrometer, but I haven't seen a reply. Which is it? See post #4.

 

[Mer-man]

Try rebrewing and pitch half the slurry from this batch.
I’ve got a lager going at 49F with 2206 and it dropped from 1.043 to 1.034 in 24 hours, so “slower” is relative.
With a lager ferment, triple the yeast you’d use for an ale. Hope that helps!

 

[okiedog]

Refractometer?

Use this calculator to account for the presence of alcohol. Otherwise the reading is no good. I'm starting to keep count of how many times I make this post (I think this is #4).

Good point! I failed to consider that he might be using a refractometer.

 

[elgee]

I got it down to 1.014 after the diacetyl rest, so that was good enough for me. Its now lagering at 35.

 

[Brettomomyces]

Lagers are slower to get going then ales, but not that slow. 3/31 expiration date puts packaged date around 11/30, which puts yeast viability around 24% or 48 billion cells in the two packs combined instead of 200 billion if fresh. Using Brewer's Friend yeast calculator, a 1.056 lager needs, at their lowest lager rate, 392 billion cells. 1.6 liter starter (assuming 1.040 starter gravity and a stir plate) would = 304 billion cells, which is 88 billion short of target. So underpitching, plus colder temps would explain while it's very slowly moving. With lagers I would highly recommend using a yeast calculator and pitch accurate amounts.

Weird thread to just randomly drop this in but this was recently passed along to us from a White Labs rep.

Cheers

 

[jdauria]

Weird thread to just randomly drop this in but this was recently passed along to us from a White Labs rep.

Cheers

That's interesting. I know yeast calculators are not the bible when it comes to cell count, but 72% viability after 6 months per that link seems crazy...but I just found the same info on their web site. https://www.whitelabs.com/news/purepitch-shelf-life That really throws off everything and means I have been overpitching like crazy.