Looking to start reusing yeast after fermentation and cultivating my own yeast using the bootleg biology kit. My question is how long can you keep the yeast in the vials before they go bad?
I've used some ranched yeast that was a year old successfully, just needed to step it up to pitching size.
I keep at least 100 ml of thick clean slurry from over-built starters under about as much spent wort for almost a dozen strains going using mason jars sitting in the bottom of my cold conditioning fridge. Only ever lost one - my Spencer "family" yeast went to Heaven because I forgot to tighten the lid and it got oxidized AF - but I could build anew from a couple of bottles of their beer
But you're looking at plating. Whole 'nuther ballpark - one I don't play in, but I expect someone that does will come along shortly...
@day_trippr: What's your procedure for using one of your ranched strains. Do you build a starter from the entire 100 ml each time or another approach? What size starter do you use? Thanks!
For reference I typically end up with 10.5-11 gallons in the fermentors, and use a 1M/ml/°P pitch rate.
If I have a strain with 200 ml of clean thick slurry I can do a single step 3.5 liter stirred starter in a 5 liter e-flask. That will allow splitting the result 3 ways with one to store and the other two to pitch (I use a pair of carboys).
Otoh, if I only have 100 ml to start with, I have to step up twice to hit the same cell count. It's actually that simple
While I have direct-pitched from the fridge on those rare outlier events I rarely have more than 200 ml of any strain on hand as I prefer pitching a "fresh generation". I usually have easily evident activity within 12 hours of pitching and gassing the fermentors which is always encouraging...
I have found this to be 100% strain dependent. Before I had a -86 C freezer for my Yeast Bay work I would store some cells in a frost free -35 C and try to evaluate as fast as possible and bank with WL if it was good or toss it. Totally hit or miss. Some strains kept fine for 6-12 months, other I sadly lost after a few months. If you find something you really like, I would highly recommend finding someone to hold onto it for you in a -80 C freezer. Always happy to help if you have something you think is unique, I have plenty of -80 C freezer space! Hit me up at [email protected] if you find something you want preserved.
