Yeast Family Tree/most efficient way to propagate yeast

[Beerandgranite]

I am currently overbuilding yeast starters to store yeast for the next brew day, and i am hoping to take a single pack out to around 8+ brews for no real reason other than an arbitrary goal. i guess some what to save some money, although the dme cost for lager starters is adding up. and also to save some trips to the LHBS. in any case my current method is as follows and as seen attached image labeled "yeast tree":

• Add original liquid yeast pack to starter
• increase cell count via starter
• split starter in half, set aside half in sterilized mason jar to be used at later date, add other half to step up
• pitch stepped up starter after cold crash and decant
• repeat process starting with yeast from mason jar after cold crashing and decanting

I am three brews into this method, and if the yeast calculators are to be believed i am actually increasing the cell count of how much i am storing/pitching each time.
However i am thinking of switching over the method outlined below for convenience:

• Add original liquid yeast pack to starter
• separate into 4-5 100b cell mason jars
• add mason jar to starter+step up to be pitched
• repeat each for each brew until only one mason jar remains
• repeat entire process staring from remaining mason jar

is there any benefit one way or another?

 

[Jack Arandir]

Number 2 is better. Fewer generations gives less opportunity for mutations and infections. Take your first starter (generation 1) and put it in ~5 jars. When you need yeast, take one of the jars and propagate it.

Another option is to use 50mL centrifuge tubes. You can fill over a dozen vials from one starter. Whenever you need yeast, spin up a vial to 500mL, yielding 100-200B cells. Do a second stage if you need. Breweries often build up starters using the 10:1 thumbrule: 50mL of yeast can be spun up to 500mL. 500mL can be spun up to 5L, etc.

If you're really advanced, add glycerol to the vials and freeze them. Extends the shelf life to a decade.

 

[day_trippr]

This is an interesting question. I can see the point provided above, but it's not a clear win: if one simply stored overbuilds in mason jars the cell viability loss makes pitch rates less and less deterministic with increasing time. And while slants can be almost immortal they require more front-end prep and back end resurrection with many growth cycles to get to a decent pitch.

I've been using the first technique forever. I kept a run of 1318 going for over a year of brewing hazies every few weeks with hardly any effort and no apparent down-side...

Cheers!

 

[beren]

Check out Maintaining A Healthy Yeast Bank Long Term

It’s what I do. Make a 1l starter, split into 10 and freeze for up to a few years