Good morning Gents (and Ladies!) There is a local shop here in town that has probably 25 different vials of yeast that is "expired." They are offering it a discounted price, but I think I am going to offer even less. My plan is to build up all of these yeasts with starters, decant, and throw the new yeast cake in the original vial and refrigerate. My questions are: 1) How long is the actual lifespan of liquid yeast? Does anyone really know? I would imagine that I could build up a new colony with time and patience from even the most minimal amount of yeast. 2) What is best practice for preserving yeast? Thanks in advance!
“How long is the actual lifespan of liquid yeast? Does anyone really know?” There is no simple answer to those questions since it is dependent upon storage conditions. I once brewed an Oktoberfest with a free Wyeast smack pack (2633) that was over 11 months old (I made a yeast starter). That Oktoberfest beer turned out excellent. Here is an article which discusses yeast ranching: https://byo.com/mead/item/1662-yeast-ranching-advanced-homebrewing The topic of yeast ranching was discussed in this thread: https://www.beeradvocate.com/commun...-healthy-yeast-strain-for-a-long-time.425983/ Cheers!
Over the years I have successfully made starters from expired yeast. Some barely expired and some significantly expired, though I don't recall how long expired exactly. If the expiration isn't totally unreasonable, you're getting it super cheap, and you're willing to make a starter, I say go for it.
I think I may just buy them and store them. Build up the starter for a brew, take some of the starter yeast and put back in the vial, label in Generation 2 and so on. We're talking about $5-7 in savings. Not something that is worth that much time as discussed in the article to me (as a homebrewer). Now if I were trying to replicate the same beer forever, way different story. I wonder if there is a story out there where a commercial or bigger brewer lost their "mother" batch of yeast for a beer. I also wonder how old Annheiser-Busch's yeast is and the other older breweries.
You may enjoy reading the book Yeast by Chris White and Jamil. It will answer your question as to how you could store these yeasts and how big breweries keep their cultures.
Its not a drop dead deal. Its a % viability deal. as long as a few cwells survive you can make a starter.
My hbs will usually give me a buy 1 get 1 free on old yeast. They work good in a low gravity starter.
That's my thoughts exactly. Logic tells me If there are even just a few thousand cells (really even just a few...) you would be able coerce it back to life. Just would take patience and time. Which I have plenty of. I just didn't know if there was a point were the vial was literally dead. (12 months after exp. date, etc.) Thanks for all the thoughts!
Thanks for the suggestion! I think a buddy of mine has that one, I will have to borrow it. Currently working though American Sour Beer, and Radical Brewing.
There'll be plenty of viable yeast still left in an expired vial. Hell, you could essentially build up a culture of yeast from a single cell. I wouldn't try it though Maybe even a 2-step starter would be necessary depending on the expiration date, but as long as the yeast eats through a Liter starter of 1.040 gravity wort then it should be ready to take on a 5-gal batch of standard gravity wort. The reason they're cheaper is a lot of people are lazy and don't feel like making a starter, or are intimidated by one. I'd just culture the yeast right after you rack it off the cake in primary. Sanitized turkey baster always works for me. I'll suck up enough yeast/trub/beer mixture to fill a couple 200mL mason jars, put a lid on them and store them in a fridge. I've revived a few cultured yeasts after 6-8 months. I haven't gone longer than that though.
