Failed yeast?

Last night I smacked a Wyeast smack pack and left it out at ambient all day (~68°F). I came back this evening, and there was no swelling. I put it in a bowl of warm water for about two hours, regularly adding water to keep it warm, and yet it has still failed to swell.

I pretty sure I broke the nutrient bag inside, as I cannot feel it any more. I shook it thoroughly last night and then this morning. It is dated as being manufactured on the 28th of December, 2008. Is it likely that this is a bad pack?

Make a starter for it, then check back with us in two days...

That yeast is about a year old, so it's going to take a LONG time to show activity. That's one of the reasons it's recommended to do a starter with liquid yeast- to ensure viability of the yeast, as well as reproduce the yeast to give you enough to pitch. Even with a brand new package of yeast, a starter is a good idea.

Check out mrmalty.com's yeast pitching calculator: http://www.mrmalty.com/calc/calc.html
With a manufacture date of 12/28/08, he shows a yeast viability of 10%.

Dec 2008 is pretty darn old. There may be a bit of viable yeast left in there, but it isn't gonna be much. You could try to get a starter up and going, but the safer bet would be to just go out and get an new pack of yeast. I suspect any yeast you have in that smack pack that is viable may carry some off flavors from the age and amount of dead cells..

That's not a pack you just bought is it? If so I'd return it to wherever you got it and show them the date. I think they are normally marked at a discount as older less viable product after about 3 months.

It is one I just bought. This is the second failed liquid yeast I've had from the same brew store - I'm guessing they have poor turnover (I did not write down the date of the first yeast from them). I will be talking with the owner.

A HBS selling liquid yeast at 11 months old is completely unacceptable. The owner should give you a replacement for the yeast you just purchased. With rare exception all the yeast I have purchased from my HBS's have had a mfr date within the last 30 days. If he doesn't have anything that has been made in the last 2-3 months I would switch to a dry yeast for this batch, and start buying your liquid yeast from another store, or online ahead of time in the future. Bear in mind, even at 2-3 months old you have a lower viability that requires a larger starter size. Use the Mr Malty calculator that Yooper referenced earlier to determine starter size for slighty older liquid yeasts. It's pretty easy to use.

I always make a point to check the date on my liquid yeast when I pull it out of the cooler. I've never had a problem because my LHBS does lots of business both at the store and online, but I still check with the intent of seeing if there's a fresher one on the shelf if I get an oldie.

Thanks all. This is the second liquid yeast I've ever bought, and I thought I had just messed up the starter on the first one. It's good to hear that the guideline is "about a month or two old". We have three LHBS's, though one is in the next city over, so I won't be desperate for a supplier.

After a second evening, my year old 1214 packet has semi-swelled. Do you think it's worth making a starter with, or not risking a good batch of beer and getting a fresher batch of yeast? In either case I will have plenty of time to bring the starter up, but I saw a comment above saying after a year, the low viability of the yeast could lead to off flavors.

In my humble and still newbie-ish opinion, it depends on your brewing philosophy. If you lean more toward the RDWHAHB side of things, then make a starter with it. If the starter turns out ok, then go for it!

On the other hand, if you already consider the time spent brewing to be a pretty significant investment, or if you're brewing for competition, then what's another 5-7 bucks for another yeast pack?

The good news is, either way you go, you're right! If you don't have the brewing itch (got to brew RIGHT NOW), I'd probably just get a new yeast pack.

Since the yeast is newly purchased from a vendor who sold you year old yeast, I would just return it and ask for an exchange for a fresher yeast pack.

I have never used yeast that old, so do not speak from experience, but you have two potential things going against you. These are worst case scenarios. One, as many of the yeast have died, they decay like any life form. In a full batch of beer you obviously have much more yeast, but in a batch of beer this condition is called autolysis. It can occur when the beer is left on the yeast cake for extended amounts of time. How long is up for debate, but I'd think even the most optimistic brewers would be concerned about 1 year. It can throw something of a meaty flavor into your beer.

Secondly the yeast that are remaining are basically starved. They depleted their nutrient reserves long ago, and have also cannabalized the other dead cells to stay alive. They may have mutated from their original charachteristics some, and they will not be in good health. The colony will have to be brought up slowly and given very good nutrient and environmental conditions to get them back in top fighting form. It is certainly possible to nurse those remaining yeast back into a healthy colony, but I'm not sure I'd want to take the time when I could simply go back where I bought them and ask for a newer batch.

It's up to you though. If you feel like you want the challenge go for it. Just make sure to smell and taste the starters as you regrow the colonies to make sure there are no off flavors being produced.

Thanks for the advice. The LHBS which sold me the old stuff did not have any Belgian yeasts in at all with a reasonable manufacturing date so I'm already having to hit up a different LHBS. I'll return to the original one later to discuss the issue.