How big of a pitch is too much?

I'm looking to pitch a Wyeast pack that's about six months old into a 1.048 brew. Using Yeastcalc.com with Troester's stir plate method, it says if I make a 1.5L starter that it should bring the cell count up to 260 billion. I'm thinking about stepping it one time just to make sure there is enough viable yeast to do a good job. Thoughts?

Oh... stepping it up with 1L will (should) bring it up to 339 billion. Too much?

Not sure where you get the 260bn figure from on a 6 month old pack of yeast into a 1.5L starter?

How big a batch are you making? Are you brewing an ale or a lager?

My advice is to just use the calculator and not start pitching higher that recommended quantities of yeast "just to make sure".

There is an optimal pitching rate and going either side of that is less than optimal and hence cannot be recommended as good practice.

el_caro said:

Not sure where you get the 260bn figure from on a 6 month old pack of yeast into a 1.5L starter?

Click to expand...

Honestly, not sure. I just plugged everything into the calculator and that's what it gave me.

It will be an ale. 5.5 gallon batch. (Sorry, I guess that would have been good info to include in my original post.)

I'd say 339 bn is too much, that's like 30% over pitching (I was told there would be no math).

I usually shoot for about 10-20 billion cells extra, because when you decant and pitch, you're not getting every single yeast cell into the wort. 10% over should be fine.

Ok. Thanks, guys. looks like I'll stick with just the starter.