Does my 3-month-old slurry need a starter?

[Quercus]

A question for the helpful experts:

I have about a cup of yeast slurry (WLP 002) that's been sitting quietly in my fridge for about three months.

I'd like to use it this weekend; should I just warm it up and pitch the whole thing, or make a starter with a smaller amount?

I'm leaning towards making a starter with about 1/4 cup of slurry, if for no other reason than to see if it's still viable.

What volume of starter would be appropriate? I'd prefer to not have to step it up, although if I start tonight, I should have ample time for a two-step starter.

Thanks,

Q.

 

[ohiobrewtus]

It would be helpful to know how it's 'sitting' in the fridge. Is it in a container covered in plastic wrap? In a container with a lid?

Is it in a dedicated beer fridge or in the family fridge in the kitchen?

Unless it has been washed and stored in a bottle and capped and/or stored in a fridge that's use only for beer related items I'd be hesitant to use it at all.

Kitchen fridges are crawling with unseen nasties that could produce undesired results in a slurry over a period of 3 months.

 

[Bobby_M]

I agree. It really depends on how sanitary your collection was. I've used 2-week old slurry that came out OK. It smelled nice and clean (probably not a decent indicator). I so need to get a flask and some DME.

 

[Quercus]

It would be helpful to know how it's 'sitting' in the fridge. Is it in a container covered in plastic wrap? In a container with a lid?

Is it in a dedicated beer fridge or in the family fridge in the kitchen?

Unless it has been washed and stored in a bottle and capped and/or stored in a fridge that's use only for beer related items I'd be hesitant to use it at all.

Kitchen fridges are crawling with unseen nasties that could produce undesired results in a slurry over a period of 3 months.

These are all very good points.

It's washed yeast, in a mason jar, covered tightly with aluminum foil, in the family fridge, which is opened 50 times a day by the kids.

It looks and smells good, but I have to admit, the chance for contamination under these conditions is probably high.

I wonder, if I made a starter, would any undesireable qualities be detectable (I'm thinking olfactory evidence)?

 

[ohiobrewtus]

These are all very good points.

It's washed yeast, in a mason jar, covered tightly with aluminum foil, in the family fridge, which is opened 50 times a day by the kids.

It looks and smells good, but I have to admit, the chance for contamination under these conditions is probably high.

I wonder, if I made a starter, would any undesireable qualities be detectable (I'm thinking olfactory evidence)?

You'd be able to tell now if there was a problem with it. It may smell fine, but if it just had foil on it I personally wouldn't use it after 3 months.

 

[menschmaschine]

Not to hijack the thread, but what about the same situation except covered with plastic wrap and a rubber band... any better?

 

[Sir Humpsalot]

Yes, that's certainly better... but I still don't think I'd use it.


For another data point, I had a White Labs vial that was 3 months out of date, stored in the fridge. I opened it and didn't get the typical pffft! out of it. I made a starter, it took forever to start- about 3 or 4 days. It smelled good, so I pitched it into the wort.

 

[ohiobrewtus]

Yes, that's certainly better... but I still don't think I'd use it.


For another data point, I had a White Labs vial that was 3 months out of date, stored in the fridge. I opened it and didn't get the typical pffft! out of it. I made a starter, it took forever to start- about 3 or 4 days. It smelled good, so I pitched it into the wort.

I agree on both counts. It's better, but I still wouldn't use it.

If you want to ensure the viability of yeast after you wash it I recommend bottling it, capping it, and labeling it for proper storage. I've used yeast that was bottled for 6 months and it made a great starter and resulted in a great beer.

 

[Sir Humpsalot]

I've used yeast that was bottled for 6 months and it made a great starter and resulted in a great beer.

That's a really great idea... I mean, we all have the necessary equipment for that right at our fingertips... when you think about it, it'd be kind of crazy not to take advantage of it.

 

[Rhoobarb]

I agree. I keep mine in the fridge in a sealed mason jar for 2-3 weeks, max. If it's going to be a longer wait, I wash it, then freeze it in a sanitized, tightly sealed White Labs vial with some glycerine.