Using 1/2 vial of White Labs yeast for a 5gal batch?

[29thfloor]

I recently did a 1 gal batch from this new book Beer Craft that called for 1/3 of a WL vial. I ended up pitching closer to 1/2 by accident, so now I have the rest sitting in my fridge.

I'm wondering if I can step this up to a 5 gal batch and get enough yeast from what's left in the vial with a starter. I've only used prepackaged yeast so far so I've never done a starter. Not sure how to make sure I'm pitching enough yeast.

Also, the yeast has been in my fridge for 2 weeks now and I probably won't have time for another brew until sometime in Aug (gonna be away the first two weeks). Will 1+ month old yeast require any sort of extra steps (stepping up or using a stir plate or anything)?

 

[aardii]

I recently did a 1 gal batch from this new book Beer Craft that called for 1/3 of a WL vial. I ended up pitching closer to 1/2 by accident, so now I have the rest sitting in my fridge.

I'm wondering if I can step this up to a 5 gal batch and get enough yeast from what's left in the vial with a starter. I've only used prepackaged yeast so far so I've never done a starter. Not sure how to make sure I'm pitching enough yeast.

Also, the yeast has been in my fridge for 2 weeks now and I probably won't have time for another brew until sometime in Aug (gonna be away the first two weeks). Will 1+ month old yeast require any sort of extra steps (stepping up or using a stir plate or anything)?

You can definately step it up to a full vial, you'll just need to make a starter and gradually feed it more and more starter wort. I'd definately reccomend a stir plate, so you can just pitch it and leave it for a day, throw some more wort, leave it for a day, etc. Otherwise you have to stir as much as possible and when you sleep, your yeast is gonna starve for oxygen.

You want to keep your yeast in as aerobic a solution as you can for them to reproduce. Not only does it encourage the yeast to reproduce, yeast also need oxygen to help repair their cell walls after they bud. More oxygen = faster reproduction, more buds from the parent cell, and stronger cells produced. =]

 

[Clementine]

This is just like doing a regular starter just do two stages (there is more than enough info on this everywhere) then after you do a 500ml starter you can throw the hold thing in the fridge once it has fermented until you are ready to brew pull it out one or two days before let it warm up (decant if you want) then pitch it into your 1L starter. Using a stir plate or at least O2 will help build up numbers and viability.

Clem

 

[29thfloor]

Awesome thanks for the info.