Im gonna brew a batch of irish red this weekend and was wondering if it would be benefical to do a starter or just use the irish ale WL 004 straight out of the vial.By the way how long will these vials last in the fridge after purchasing?
Absolutley benefical to do a starter, especially if it has been in your fridge for a few weeks. The longer (older) the vials are the less viable (active) the yeast inside.
A couple of batches ago I brewed three gallons of export stout at 1.062. I pitched a WLP004 straight in and it worked fine: it was 10 days old.
If your red is lower O G and the yeast is really fresh it would work.
Depends on the OG.