Yeast Quantity/Yet another question

[Western Brewer]

Brewing this weekend and will be using a White Labs yeast, as I am making a half batch (2 1/2 gallons) should I still use the whole phial of yeast or reduce it some. Is it possible to use too much yeast and spoil a brew?

[steve_flack]

Personally I'd use the whole vial as you're really supposed to make a starter of WhiteLabs yeasts (for 5 gal batches) anyway. You might actually get the correct pitching rate for a 2.5 gallon batch with one vial (depends on the gravity though).

BTW, yes you can use too much yeast but you'd really have to add a lot more than one vial.

[tribs]

Try

pitching rate calculator

You have to convert your wort volume to US gallons though

I think you'll find Steve is correct however.

[monk]

I think you'll be fine. I make half batches all the time and usually pitch a packet of Safale US56 or Nottingham, both of which have a much higher cell count than a white labs vial. Like Steve said, with the vial you'll probably get the just the right amount, actually.
Good luck,
monk

[mysterio]

There is a lot of dodgy info on the WL website.

By 'pitchable' I assume they mean more than a standard wyeast pouch. Pitching a single vial will work obviously, but it's nowhere near commercial pitching rates.

Commercial pitching rates would probably be closer to a couple of packets of dry yeast in a 5 gallon batch or a large, well aerated, stir-plated starter with a liquid yeast.

[Reg]

Whoms... ?

[fizzypop boy]

who's .It duzint reely matta abowt gramma oar spelling az long az wee get the rite anser

[steve_flack]

One vial of yeast will work for 5 US gallons but it will be slow starting and it's during that lag phase that the beer is most vulnerable to infection. Basically for a 1.040 or less ale then one vial is probably OK but for anything more you should really make a starter. That said, I've made Belgian Dubbels at 1.075 and pitched one vial of yeast and they came out fine. They took well over 24 hours to get going and the Belgian styles are supposed to be a bit estery anyway.

It also depends how fresh the vial is. If it's very fresh then there's more viable yeast. You're probs OK with anything that's a special order from H&G (ie ordered specially from the states for you) but, although H&G keep the yeast properly, the cells die off as time passes reducing the cell count so stuff that's a bit older won't be as good.