[macbrewdaddy]

I live abroad and brought back 4 vials of liquid yeast to get back into brewing (You can only get dry yeast here).  Based on the concept of a starter, it seems a logical extension to me that I could grow from one vial a yeast population that could serve for several fermentations.  So if I did a starter, then split that into two more starters, then split each of those, I could end up with 4.  I've never read of anybody doing that though, and everything I read on culturing yeast seems to be more in terms of harvesting it from a finished fermentation and storing it long term, not growing the population for multiple future batches.

Does this sound logical, or am I off base here?

[bbesser]

FlyGuy over on Homebrew Talk made a great write up about producing a yeast bank, which sounds like it is what you are wanting to do.

http://www.homebrewtalk.com/f13/guide-making-frozen-yeast-bank-35891/

[morticaixavier]

A few folks on here have also had good luck with simply making twice the starter they needed, pitch half into wort and save the other half for later.

Unless you have access to a very very cold freezer the cultures will only last for so long. best bet is to make enough extra at one go that you can take part of it to brew subsequent batches. the problem with reproducing over and over is that genetic drift and chance of infection increase with generations.

So if you can make one big starter (like a 5 gallon batch of beer) and split the resultant yeast into say 10 small jars you've got 9 pitches of 1st gen yeast to work with before you have to use the 10th one to make a 2nd gen.

you still have to deal with the fact that a fridge is just not the best way to keep yeast happy and healthy long term. for that you need to freeze them. And that requires special stuff and knowledge.

[reverseapachemaster]

I used to yeast rinse every batch of beer I made. I pulled back on that when I ended up with way too much yeast in my fridge. Now I just make an extra large starter and pour a small portion of the yeast into a mason jar with boiled water (cooled, of course) and put that aside in my fridge. The rest goes in my beer. That keeps a fresh, healthy and relatively clean base of yeast available.

I've also dialed back on the number of strains I am using so that helps reduce the volume of yeast in the fridge and makes sure I am using fresh yeast. I normally just keep a lager strain, neutral-ish American or English strain and a saison strain. That covers 90-100% of what I am brewing these days. I do have a bank of frozen yeast at my parents I can tap if I need something else. Or buy something new.

[macbrewdaddy]

cool, thanks for the replies.  keeping just a bit on hand to use quickly is what I'm going for.  My idea was to seal them up in beer bottles in the fridge.

anyone have a link to a really practical guide to harvesting yeast slurry?  I would like to try it as well (I never did back when I was brewing in college, it was always so easy to just spend the 7-10 bucks on fresh yeast).

[a10t2]

anyone have a link to a really practical guide to harvesting yeast slurry?

I like this one, but I may be prejudiced.

http://www.homebrewing.com/articles/yeast-management.php

[S. cerevisiae]

I like this one, but I may be prejudiced.

http://www.homebrewing.com/articles/yeast-management.php

You brought up an important part of cropping from a carboy that many brewers overlook.

"When harvesting from a carboy, the yeast can simply be poured out, though the lip of the carboy should be sanitized first, and of course care should always be taken when handling glass."

The pouring surface of any container that holds yeast should be sanitized before pouring the yeast, including the cut edge on smack packs and dry yeast packs.  I use a cotton ball that has been soaked with 95% ethanol to perform this task; however, 91% isopropyl can be used in a pinch. One should allow the alcohol to flash off before pouring.  A large number of beer infections are pitched with the culture.. 

[S. cerevisiae]

you still have to deal with the fact that a fridge is just not the best way to keep yeast happy and healthy long term. for that you need to freeze them. And that requires special stuff and knowledge.

Yeast will remain viable on slant for two years or more when stored in refrigerator.  I maintained several cultures on slant for ten years in my first yeast bank with minimal periodic subculturing.  Freezing yeast in a -20C home freezer offers no advantage over slanting, and plated yeast that is aseptically transferred to slant is almost guaranteed to be pure (plus, one does not have to worry about accidental freeze-thaw cycles).  Now, if a brewer has access to a -80C or lower freezer, then cryostorage is the only way to go.

[beerlord]

Often I make a start 2 to 2 1/2 times larger than needed and then save half or more for later use. I then make a double size starter the next time and continue 4-5 generations.  Sometimes I'll grab some yeast from the fermenter and wash it for future use. I've cut down on using dry yeast by 75% and brew every 2-3 weeks and probably only bought yeast 3 times last year.

The only downside is if you use many different styles of yeast. I keep 3-4 different strands of yeast in the fridge most of the year.  Big money savings for me.