Washing a yeast starter to keep a healthy population.

[kilted_brews]

I have begun washing and saving yeast as part of my regular brewing process. I'm aware that yeast, as a living organism, has a shelf life even under the best circumstances. I try to brew regularly to keep my yeast populations fresh and viable but some styles (hefes i.e.) I only brew occasionally. Does anyone make a starter for the sole purpose of settling out old dead yeast, rebuilding the population, and then re-storing the freshly propagated yeast population?

 

[Golddiggie]

I made a starter after pitching most of the previous starter into a batch I brewed. This is from a strain that isn't currently available (Wyeast 1882-PC). I've had that last starter chilling in the fridge for a few days while I get other things taken care of. I will be pulling off part of the slurry, and storing it in the fridge (in a 50ml vial) for use in a month, or two. I'll make a starter (or two) from that to pitch into the batch. The rest of the slurry will be prepared and frozen at <0F until needed again. I have the glycerine to mix up to use with freezing and such, so it's just a matter of doing it. I also have enough vials to do the job. I even did a test freeze with one to see how far I can safely fill it and NOT have it break on freezing.

 

[kilted_brews]

So your method, if I follow correctly, is to make a larger than needed starter, pitch the right amount of yeast into your wort, make another starter from the remnants of the first starter, then freeze the slurry from the second starter.

What is the self like for yeast frozen in glycerine? How technical/specialized is freezing and reusing yeast in glycerine?

 

[Golddiggie]

That's the plan. I've not yet processed the yeast from the last step (starter with what I reserved from the amount pitched).

There's a thread about freezing yeast that has a lot of info in it.

You can score the glycerine from Amazon at a good rate (better than B&M stores).

Just plan to make a starter (or two steps) when you've thawed out the amount frozen. You also freeze in vials. You also need a freezer that will get to -20C (-4F) and below. Luckily, my food freezer does this. But, I'll be using a cooler box to keep the vials from getting influenced from the opening/closing of the freezer.

 

[kilted_brews]

Sweet! I'll look up the glycerin freezing thread. I have a chest freezer that holds between 1F and -3F on the warmest setting so I can definitely drop it a little for this use.

I have to laugh because I knew that building my stir plate would lead to more facets of the hobby...looks like freezing yeast in glycerin is my next stop down that road. 'Home brewing' is somewhat of a misnomer since, even though the hobby starts as simply brewing beer at home, it tends to lead us down many diverse paths.