I'm planning to brew a Belgian Pale Ale this weekend (OG 1.052), and the vial of WLP575 that was sent to me with my order is past it's "best by" date by about 10 days. I called the shop that sent it to me, and it was the last one they had. I was assured that the yeast had been kept refrigerated as long as it was at the shop and it went into my fridge as soon as it was delivered.
According to the Mr. Malty yeast calculator, this yeast has only about 10% of it's original viability. I do a starter with all my batches, but should I do a two-stage starter with this since it's likely to be pretty weak? For a beer this strength, I would normally do a 1L starter with a gram or so of Wyeast nutrient at about 1.040, let it grow for 36 hours or so, pop it in the fridge the night before the brew and decant the spent wort before pitching. I was thinking this time I might grow it once in a lower strength starter (maybe 1.030 or so), refrigerate, decant and pour fresh 1.040 wort on top and give it another day or so of fermentation to get my viability back up before pitching into the beer on brew day.
Is this overkill? Should I just go with my normal starter procedure and pitch as usual? I'm sure someone here has used a vial past it's "best by" date; how much is viability really affected?
Thanks for any input, I appreciate it.