Yeast Viability Question

[vinobrew]

Real world issue. I went to the LHBS last week Friday and picked up a packet of WY1187 Ringwood Ale yeast I was going to use on an English Porter this weekend. The original packet I grabbed had an expiration 1/9/26 date on it, so no worries, I'll do a quick starter to get things rolling and we should be good. As I'm getting ready to check out, I noticed there was some crap on the packet, so I "exchanged" it with another cleaner one on the shelf. In my last second haste, I didn't look at the expiration date and assumed it would be the same. Fast forward, I go to get my starter going on Wednesday (knowing Ringwood has a lag factor) and I notice the expiration is 9/15/25. Uh oh.. Brewer's Friend yeast calculator is saying there is ZERO viability in the yeast packet. Panic sets in as this now starting to impact my planned brew day. I decided to give AI (Google Gemini) a shot to see what it would say. Attached is what the feedback is. I thought it was pretty good. What do you think?

The end result is I need to likely substitute my WY1187 for a slurry of fresh Safale 04 or a new dry yeast packet of Apex London yeast if I want to brew the English Porter this weekend.

 

[Donoroto]

My thought is to try the starter. You’ll know in half a day if it is viable or not. Worst case, same wort can be used for another starter if that yeast is truly dead. I bet it’s good enough though.

 

[Craigerrr]

Was the WY1187 a dry or liquid yeast?

 

[HighVoltageMan!]

Like Don said, your best bet is to do a starter. One liter to start with. If it shows a fairly fast start, you likely had at least 2-6 billion cells that made it. If you show no activity in 24 hours, I would think it's like done.

If you can get a decent amount of krausen out of a one liter starter, you can pitch the whole thing. It's best to pitch at high krausen or just after the krausen starts to fall. If it shows a slow start, it better to do a second step in your starter, 2 liter.

The second way is going to take longer. Star with a 300-500ml starter and run it until you see some krausen (may take 24-36 hours). Crash cool it in the refrigerator, wait a day and then make a 2 liter starter. The best yeast from a starter is just after the yeast hits high krausen and it still has some food left, so I typically crash cool my starters just after they hit high krausen or a little time after high krausen to get the healthy yeast possible.

Most of the time there is still some yeast to salvage, but it's a bummer to realize you just bought old yeast. I've done it on occasion.

 

[vinobrew]

Was the WY1187 a dry or liquid yeast?

Liquid.. in a smack pack.

 

[vinobrew]

Like Don said, your best bet is to do a starter. One liter to start with. If it shows a fairly fast start, you likely had at least 2-6 billion cells that made it. If you show no activity in 24 hours, I would think it's like done.

Happy to report out activity started within 24 hours and it hit krausen at 36 hours. This is also a yeast that is notoriously a slow starter. Yes, the plan AI told me was exactly what you said. Likely not enough yeast survived to carry through a full 5 gallon beer pitch with the 1L on the stir plate. AI calculated it at 88% of requirements at the end of the 1st starter. I'll need to do a 2nd with a 2L starter to get the sufficient pitch rate.