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Should I re-pitch?

Northern Brewer General
#1

So I’m working backwards on this a bit, but here’s my predicament:

I brewed a Patersbier on Sunday using a single smack pack of Wyeast 3787, (note, I bought it the same day, and I was in a hurry to get everything done and brewed on Sunday). The manufacturing date on the pack was December 13th, which had me concerned that the viability would require an additional smack pack or a starter. When I asked the guy at the NB Milwaukee store if I needed a few additional packs due to the age of the yeast, he didn’t seem to know what I was talking about, and just assured me that a low gravity beer like a Patersbier (OG = 1.046) would be fine with only one smack pack.

I brewed Sunday, and I have about a 3 inch layer of Krauesen forming as of today, with relatively low airlock activity (I know these aren’t necessarily reliable indicators of attenuation). My concern is that I checked the yeast viability on Mr. Malty’s website today, and lo and behold, it was only at 30%! According to their pitch rate calculator, I would have needed more than 4 of these smack packs, or 2 starters, to have the proper pitch rate. Should I add several more smack packs and/or a starter at this point, or wait to take a gravity reading in about 10 days? I would prefer to avoid wasting additional weeks if I can.

Any feedback, as always, is appreciated!

#2

The fact that you have a 3" krausen is promising. The viability calculators are worst case scenarios. There’s no way to accurately judge the viability of a smack pack without a microscope. How long was your lag phase before you saw active fermentation?

#3

I would say about 18 - 24 hours. Seemed to take a bit longer than usual.

#4

At this point, I’d just let it ride. You may have under pitched a bit, but at this point the yeast already grew/multiplied and are doing their thing. The yeast have already added some flavors to your beer and I don’t think pitching more yeast would counteract that. If anything (and I’m just guessing here) you may have stressed the yeast a bit, which would cause them to throw off some stronger flavors, but in a Belgian beer that may be a good thing.

Let it ride. See what you get. Live and learn.

:cheers:

#5

You are fine at this point, no reason to add any more yeast. Any “damage” due to underpitching, yeast stress, off flavors etc, will already have happened by now either way. I don’t think it will be a big deal though, seemed like the yeast got off and running in a reasonable amount of time

#6

nob question perhaps = but is a Dec 13 date really that old? I know the earlier the better, but this is just about 3 months old. At least to the pouint where you needed maybe as many as 4 packs?

#7

It’s old in the sense that you should definitely make a starter with it. Not old to the point where it needs to get thrown out or anything.

#8

It’s old in the sense that you should definitely make a starter with it. Not old to the point where it needs to get thrown out or anything.[/quote]

That should be a commercial for Cialis or Viagra as well.
"“Hey dear, just remember - I am old in the sense I need a starter now and then, but not to old that you should throw me out (ha ha)”

#9

I recently did a test. I bought two expired yeasts from my LHBS at half price. One was a Wyeast smack the other a White Labs vial. The smack was expired July last summer, the vial expired last fall. I made a qrt. starter for each. I made one beer with an O.G. of 1.070 an other one 1.065. Both took off like a house-afire and finished to completion in two wks. Both beers tasted good, like normal. I’m not sure I would have attempted it, but those guys said they have done it before, and aren’t afraid to do it again. It made me change my perspective about expiration dates. I think I will still buy new, but I wouldn’t be afraid to do it again.

#10

I’m glad to hear that somebody’s actually tested the validity of validity! Moving forward, I’ll be sure to make a starter with anything beyond 3 months old, which I would’ve done this time if I wasn’t in a rush. Thanks for the feedback!

#11

I would take that one step further and say you should almost always make a starter with liquid yeast and to use a pitch calculator to determine the size of said starter.

#12

I would take that one step further and say you should almost always make a starter with liquid yeast and to use a pitch calculator to determine the size of said starter.[/quote]

9 times out of 10 I do when using liquid yeast, (this just happened to be my 10th time!). In any case, I’m keeping my fingers crossed that this batch will attenuate properly, but in case it doesn’t, would adding another pack/starter after 10 -14 days cause any harm to the beer? Just trying to think ahead in case of the worst.

#13

Chances are your beer will attenuate properly you just may have off-flavors from underpitching due to yeast stress. Since the lag time was so short, its a good sign that there was a decent amount of cells to tackle the job so I wouldn’t be worried.

Low attenuation is more often an issue of wort fermentability than underpitching.

#14

Update: It’s been two weeks since I brewed this beer, and the SG is only 1.017 (OG was 1.045). Should I wait it out a while yet, or re-pitch at this point? I’m not sure if anybody’s brewed with WY 3787, but I’ve heard that it can be a very slow attenuating yeast. Any truth to this?

On a separate note, I was hoping to rack today, as I need to free up my primary 6-gallon carboy for another batch. I should be safe fermenting a new batch in a 5-gallon carboy, provided I use a blow off hose, no?

#15

Are you aware that the date on a Wyeast pack is the manufacture date, not the expiration date?

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