I have about 120mls of WLP002 slurry that’s been in the fridge for 5 weeks and I’m gonna pitch it into 2.25 gallon batch of a 1.059 ESB. Mrmalty says my viability is such that I need about 112mls. Would it still be advisable to do a smallish 600-800ml starter the night before to ‘wake them up’ from their 5 week dormancy or just pitch 'em. 
Thanks for any suggestions
Stevo
I think a starter that small might do more harm than good. I’d either pitch as is, or make a bigger starter and store or toss part of it.
That’s kinda what I was thinking… just pitch it. May possibly be a longer lag time but I probably won’t shock the yeast and I’ll hopefully get good growth. 
Shoot, Denny, ya got me thinking…I made a 1qt starter Wednesday from maybe 4-6oz of Wyeast 1084 slurry I harvested on 3/21. Think that would cause more harm than good? I plan to brew a brown porter on Saturday with it.
Strictly guessing here, but that’s the smallest I’d go. I base that on this from mrmalty.com…
(Neva) Parker (of White Labs) says putting a fresh vial of yeast into 500 ml of wort and letting such a small starter go to completion can actually leave the yeast less ready to ferment a batch of beer. The yeast do not rebuild their reserves and have very little increase in cell mass.
The minimum starter size for significant yeast growth from a vial or pack of yeast is 1 liter. One vial or pack into 1 liter results in approximately a 50% increase in cell mass.
Hmm, perhaps I shouldn’t use this yeast then? It was probably 2 or 3 vials worth of yeast, if not 4. I just wanted to get them going again. I have another jar of about the same amount of yeast. I could use that, and step this current start up to grow more yeast, maybe?
OP - sorry to hijack your thread…
i make two gallon batches and i just leave the yeast slurry in the bucket and put the next batch right on top. do it a few times before i dump the yeast and start over.
I can believe this if the vial already had high viability and yeast count. However, its questionable if that slurry has either condition. I wouldn’t consider adding that slurry unless it was proofed with a starter. In addition, that starter should be continuously aerated to enable the yeast to improve their sterol reserves.
A 1 liter starter makes sense for a fresh vial, but a smaller starter could be OK for a less viable slurry.
Go say 12-18 hours on a stirplate then pitch at high krausen?
My standard stirred starter volume for 3-gallon batches is 600mls, and that’s a starter that has been propagated from slant with only one intermediate step.
Pitching the crop into 600mls of aerated wort 12 to 24 hours ahead of time will allow you to separate the live cells from the dead cells and break, as the live cells will be in suspension by the time you have chilled your batch. However, I would not put the starter on a stir plate. You need to be able to pitch the liquid in order to be able to separate the live cells from the dead cells.