Should I do a step up starter-first time questions

Hi all, I bought a white labs eng ale WLP002 and just noticed its best by date was almost a week ago

WL says it's yeast was made 4 months prior to the best by date so mr malty gives it about a 10% viability. I plan on brewing a nut brown and accordingly to mr malty I'll need about a 2 liter starter.

Given my supplies on hand I'm going to do a 1.5 liter starter and wanted to know if I should do a step up starter or just the one 1.5 liter without doing a step up?

I've done a few starters before but not a stepped up one, do you think it's necessary and if so, could you advise on quantities/procedure?

Thanks in advance!

 

I find it hard to believe that a yeast one week out of date is only 10% viable. Something seems off there. Personally, I think you would be good just doing the one starter for an ale, but if you want to be absolutely sure, do the second- it won't hurt. I should also note that when you do the first starter, if it seems slow or takes forever to start fermenting - then absolutely do the next step up.

 

I will say that if you have the time, two 750ml starters will probably yield more yeast cells than a single 1.5L starter. I prefer yeastcalc.com to mr malty (purely preference) mostly because of the stepped starter tool.

 

Mr Malty is pretty conservative with their viability. If "best by" was only 1 week ago, then you would have had 11% viability or something according to mr malty? I highly doubt whitelabs would risk their reputation by selling at such low viability. The whitelab website claims 75-85% viability after 1 month, and mr malty uses 75% ie the low end of the range. That is perfectly reasonable choice for relatively fresh yeast since 75 billion vs 85 billion would be only a 13% grow difference On the low end though, 10 billion vs 30 billion is a 300% difference.

Anyway, a stepped up starter is basically the same as a regular started. If you have 1.5L to work with, you can do a 0.5L starter to get you back into the cell count range of fresh yeast and then step up to a 1L starter.

 

From what I understand the "best by" date is 4 months after the yeast is packaged so I plugged Sept into Mr Malty and that's how I came up with the 10% viability.

I'm thinking this yeast was sitting around this brew shop I got if from. It was a small, relatively new shop (opened in Sept 2013) that I happened to come across and thought I'd give him some business since he was helpful.

I've never used White Labs before and didn't realize the best by day was 4 month from when it was packaged.