In early November, a homebrew supplier mailed me several packets of dry yeast. It should have arrived in two days. It was late, and before it arrived, I had to travel for work, so I figured these packets of yeast would sit in my mailbox for a week and could end up being worthless. When I got back, there was still no yeast in my mailbox. I emailed the supplier, who could not track it (it disappeared once it arrived at an intermediate post office), and they refunded my money. Fast forward to today's mail delivery, and my yeast finally arrived. For nearly two months, it has been in the mail stream. The package itself is in good shape, so I'm guessing it didn't get handled much, but I have no idea whether it was exposed to extreme temps. The yeast includes one lager pack (Mangrove Jack California Lager) and my next beer to brew is a high gravity beer(Baltic Porter). Rather than use the S-23 that I stepped up for this purpose (don't think I want to risk those esters) I was thinking I would use some dry ale yeast on hand for that beer. But now I have this lager yeast that I originally thought I might use for this purpose. I'm thinking I'll do some step up starters and see how it does. Or I could not risk it and buy more yeast. Thoughts?
Dry yeast is pretty durable. I attended a presentation by Kevin Lane of Fermentis at NHC 2015 and he stated: Dry yeast stored at room temperature will lose 10% of the yeast cells over one year of storage. Dry yeast stored at refrigerator temperatures will lose 5% of the yeast cells over one year of storage There is some benefit to storing dry yeast cold but the difference between 5% and 10% is not a huge difference. Cheers!
I do not quite follow which yeast is for which beer and your s-23 fears mainly because I do not use those strains. However, I doubt the extra time in the mail had much of an effect on the dry yeast themselves, especially this time of year. If you do not want to deviate from the original plan I would stick to it with confidence.
Mostly I'm looking for thoughts about the viability and provided more info to make it more confusing. Here is the progression of plans for this Baltic porter. I left a few out of the original post to make it easier to follow along . Plan A: Make low gravity lager with MJ Calilager. Re-use yeast for Baltic Porter. No longer under consideration as the yeast was lost in the mail. Plan B: Make low gravity lager with S-23 and re-use that yeast for the porter. Started down that path. I recovered the S-23 and it is in the fridge. However... Plan C: My low grav lager was not to my satisfaction and I don't want to use the S-23 on the big Baltic (probably will ditch the yeast I recovered; I posted about it elsewhere and didn't want to rehash). Use something else from my dry yeast stash, like MJ Liberty Ale yeast, stepping it up as needed. Plan D: Pony up the money for postage and order a couple packs of the MJ Cal Lager. Was going to do this later this week. However... Plan E: Only possible as of today -- make the batch with the recently arrived MJ Cal Lager yeast that has been sitting in a mailing envelope, somewhere between s. and n. Wisconsin for 53 days. Step it up with a starter.
Nice info, Jack. I'm in no position to debate a dry yeast expert, but I would have guessed viability loss was higher, because I believe they put 2 year expiration dates on them (the Windsor I just pitched says EXP 12/2017). Of course, no one is saying what the criteria for considering a yeast expired is, and I suppose the mortality curve is not likely to be linear in any event. I'm guessing dry yeast is less susceptible to extreme cold since there is no water expansion to lyse the cells. If it was left in a truck, for example, it could have experience -10 to -20 F in the last few weeks.
From the Danstar (Lallemand) website: “I would like to know how long dried yeast stored in the refrigerator (under 40 degrees F) can be expected to be useful? I'm sure that studies have been done like those with liquid yeast discussed recently, and my own experience has shown that we can expect at least some dried yeasts to last two years or more. Also, is there a significant difference between different brands of dried yeasts in how long they can be stored and still be usable? The length of the shelf life is very much strain dependent but there are also slight differences within the same strain from production to production; yeast is a living organism after all. In general we give a shelf life of 2 years and that is basically the minimum for which we guarantee that the yeast still performs to specs. We test our yeast every 3 months to control the shelf life and find that the yeast often shows good viability and activity even beyond the guaranteed shelf life. We had for instance a Windsor ale yeast that performed still very well after more than 3 years. So you might be ale to use the yeast after the shelf life is expired but we can guarantee you only 2 years shelf life. This of course requires that the yeast is still in its unopened original pack. Once dry yeast gets in contact with oxygen and moisture activity and viability will drop.” http://www.danstaryeast.com/articles/dry-yeast-storage Cheers!
I think I'd try this. If you don't get any activity on the starter after a few days you should boil it and use the wort for another yeast.
