How to revive this old, unopened WLP300?

[TripleC223]

I visited an out-of-town homebrew shop this week and picked up some WLP300 Hefeweizen yeast to brew a hefe. However, when I got back home the next day, I saw the "best by" date is July, 2017, making it 7-8 months past its prime. Mr. Malty estimates 1% viability.

I'm a little miffed at myself for not checking the date before I bought it, and miffed to a lesser degree at the homebrew shop for selling such expired yeast at full price. But either way, it's too far of a drive to try and exchange it, so here I am.

I know I need to make a starter, which is fine, but I've never used yeast that's been so far removed from its manufacture date. If I make a traditional starter (2 cups water, half cup DME), would that give me enough cells for a 3-gallon batch at 1.048 OG?

If not, can I make another starter from the first batch by just dumping another dose of starter wort? What's the procedure for doing a two-stage starter like that? Do I need to pour off anything from the first starter, or should I just keep it all in one container?

 

[mirthfuldragon]

Look up culturing yeast from bottle dregs. Essentially, start with a smaller starter, then step that up, then step it up again.

 

[flars]

The yeast is very stressed and sick. A traditional 1.040 starter wort will probably shock and further reduce any viability that the cells may have. Start with a half liter starter wort of 1.005 SG. Make a half liter of 1.010 SG starter wort if the first starter shows some life. The same volume starter wort can be used because the inoculation rate will still be much less than if nearly fresh yeast were being used. Go to a one liter starter wort with a SG of 1.040 if step 2 seemed to propagate more new cells.

Good luck.

 

[brewcat]

Personally I wouldn't mess with it. I thought about reviving some older yeast but it wasn't worth the time when I can buy a fresh pack. Call the homebrew shop. I would think they would remedy the situation. Otherwise start slow.

 

[65C]

It will likely revive just fine - yeast are hardy buggers - it may take two feeds or something

I love the feeling of reviving one - it's like growing a plant - until I have a bad experience with it I'll keep advocating it - but I've been reviving yeasts of various sorts for years without a problem so far

 

[TripleC223]

As a follow-up, the yeast seems to have woken up.

I did two separate feedings, and the second one did the trick. First I pitched it into a starter wort of 2 cups water and a half cup of Pilsen DME and didn't see a whole lot of activity. After 24 hours, I created another starter wort of the same contents and dumped it in, and it's been foaming like crazy. I have tin foil over the opening of my gallon carboy where it's fermenting, and every time I shake it, it sounds like the gas is going to blow the tin foil off.

Still slightly nervous about pitching it, but it's going into a 3-gallon batch so I believe it should have reproduced enough to use.

 

[RPh_Guy]

Did it smell like banana?

 

[khannon]

This.. Yeast is pretty hardy. Yes, a starter is a good idea especially to hit proper pitch rates, but depending on what you are brewing (saison/hefe) stressing them a little is not the biggest deal, and can even add to some desireable ("off"?) flavors.