Yeast advice

[arnie7781]

I either misread the malty calculator, or underestimated the differences with using yeast that's about a month away from the expiration date.

I currently have a 1 liter starter on my counter at room temp (68) that contains 1 vial of WL13. Problem is it should have 2 vials. So, tomorrow is Friday and I'm planning on brewing Saturday morning. Should I just drop by the brew shop, pick up a vial and add it to the starter and not chill it over night? Or chill the starter over night like I planned and add the 2nd vial when I pitch the slurry.

Suggestions welcome. Thanks.

 

[ercscotty]

What are you making? Has the starter been on a stir plate this long? Why are you chilling it before pitching? I thought putting yeast to sleep (unless it's a lager) would put them in rest when your intention is to keep the alive, bouncing around, and eating up the O2 of the starter....I may be wrong...

 

[michaeltrego]

If the "Best By" date is one month from now, it appears as though you started with approx. 33% viability or 33 billion yeast cells. Assuming you are brewing 5 gallons of 1.048 English style ale with WLP013, according to Malty the target pitch rate would be 177 billion yeast cells needed. Assuming you're not using a stir plate, your 1L starter will get you to about 67 billion healthy cells. So adding another vial of 100 billion fresh cells would get you right about on target.

 

[jar1087]

What is the starting gravity of your brew? Has the starter developed a kraeusen or shown other evidence of activity? Also, with a starter that small, you can just pitch the entire thing, instead of just the slurry.

@ercscotty - Re: chilling of a starter. Getting the yeast active is not the only purpose of a starter - it also serves to grow a larger population of yeast. Ideally, the yeast would be at the peak of their growth (high kraeusen) when they are pitched. However, a good alternative is to allow the yeast to grow to the appropriate pitching population in the starter and then complete the fermentation of the starter wort, thereby replenishing their glycogen reserves so that they can be ready to start fermenting at a later time. This allows a starter to be made up to a week or two in advance of brewing and then stored chilled until it is pitched. The chilling also causes the yeast to drop out of solution, whereupon the spent starter wort, which you don't really want mixed in with your beer (unless it is a small volume - e.g. 1 liter) can be decanted off and only the yeast slurry pitched into the fermenter.

 

[arnie7781]

Oatmeal Coffee Stout 1.050 og.

Starter looks fine. Maybe a little flatter than usual. This is easily the oldest yeast I've tried using and I'll definitely pay closer attention to the dates before leaving the store.

Is 1 liter generally the cutoff in terms of deciding whether or not to pitch the whole starter or the slurry? One liter of starter still seems like it could negatively affect the beer. No?

Thanks for the quick responses!

 

[jar1087]

I usually pitch the whole starter when it's at high kraeusen, rather than letting it finish, chilling, decanting, etc. even when the starter is as large as 2 liters; I figure that I would rather have active, healthy yeast and add a bit of spent starter wort than have somewhat sleepy yeast and risk a sub-optimal fermentation. Given that you're already concerned about yeast counts and health, I would recommend going that way as well. If you think that you can time it correctly, you could add say, another liter at high kraeusen to increase your yeast population.

Also, I should note that I usually pressure can excess wort from previous batches and then use that to build my starters, so I can usually choose a wort similar to the beer that I am brewing with which to build my starter; that way I'm not unduly influencing the character of the beer even when I pitch the whole starter volume.

 

[jar1087]

With a really large starter (3-4 liters), like for a lager, I do decant.

 

[rollinred]

What you should do is let the starter taper off. When it does add another little batch of boiled and cooled DME. The date doesn't mater as much right now but you should be able to boost the cell numbers by creating multiple starters.