Liquid yeast lifespan.

I purchased some liquid yeast online last year and happened to use half of it. I just saw it sitting in the fridge and wondered if I should hold off on going to the home brew store tomorrow to buy wine yeast.

What I have is a vial of WLP775 and a smack pack of Wyeast. I only used half of what I ordered last pressing season. Show I throw it in a starter and hope for activity tomorrow morning? Or am I up the creek?

chevalcider said:

I purchased some liquid yeast online last year and happened to use half of it. I just saw it sitting in the fridge and wondered if I should hold off on going to the home brew store tomorrow to buy wine yeast.

What I have is a vial of WLP775 and a smack pack of Wyeast. I only used half of what I ordered last pressing season. Show I throw it in a starter and hope for activity tomorrow morning? Or am I up the creek?

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You know, I would probably just get a new vial of WLP775 if I was you.

Having said that, I think most calculators overestimate decrease in yeast viability over time (they assume it's linear, because it's easier to calculate, which means at 20-something percent per month, your yeast will all be dead in 4-5 months). In reality it's probably more resembling exponential or power law decay.

There are people who report reviving a year or even 2 year old yeast, but you may need a step-up starter. I have definitely had some success with reviving "old" yeast - yeast that has been stored properly at 35F or so, for 8-12 months. But I try to not reuse yeast older than 6 months, as a general rule.
I did it for fun and for experiment, but I think the answer may depend on your storage conditions, and on the yeast strain.

I am actually pretty confident your yeast is still viable, but to revive it and step it up will take you more effort/hassle than just driving to the store and paying $6.99 or whatever for another vial. And you don't run the risk of losing or compromising a batch of beer.

I believe I will try to activate it. Just "smacked" the Wyeast pack and will see if it is swollen by morning. Think I'll ramp it up if I see any sign of life. I'm gonna boil some juice and see if I can get the 775 to start. Apples caught me by surprise this year. The yeasts I have needed to be ordered online. I have a choice of 1118, 1116, 71B and a few other wine yeasts along with a small handful of beer/ale yeasts at the local homebrew shop. This is what happens when you live in a town of 8000 an hour away from a city of 750,000!

Not that the wine yeasts are entirely bad. Just had a 1118 and a 1116 cider yesterday and enjoyed them both.

Can anyone tell me what they think of S04 and Cider House Select yeast?

chevalcider said:

Not that the wine yeasts are entirely bad. Just had a 1118 and a 1116 cider yesterday and enjoyed them both.

Can anyone tell me what they think of S04 and Cider House Select yeast?

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S04 is my favorite cider yeast so far.

A bit of an update... I pulled WLP775 and Wyeast Bavarian Wheat Ale yeast out of the fridge after being in there for a year. The manufacture date was nearly 15 months ago. I boiled 1/3 gallon juice with nutrient for each variety, let it cool and pitched the yeast. The WLP775 started nearly right away and the Wyeast took better than a day. Both are rolling and will be pitched into juice in a few minutes.

Not that I am trying to bump my own thread but....the badly expired yeast woke up in a starter and I pitched that yesterday. I also pitched a pack of S04 sprinkled onto the must dry. All three of the batches are fermenting but the two old yeast that were put in starters first are going like a bunch of hungry hippos...to the point where I might benefit from a blow off tube!