Frozen Yeast Bank - Part 2

Link to Part 1

In part one we covered preparing the vials for the frozen yeast bank with glycerine and a pressure cooker standing in for an autoclave.  Part two will cover getting the yeast into the tube and the freezing process.  The better your procedure here the better the chance that you get a good culture into storage that will survive for a long time.

In this example we'll be using some washed yeast from a fermentation.  Ideally you would want to pull yeast from your starter since it hasn't gone through a fermentation of an actual beer with hops, trub, and greater chances to have infection present.  This is just what happened to be on hand for the example.  If you haven't washed yeast before look it up, it's way easy and will give you options for reusing yeast a few times in shorter windows. 

Washed Yeast from a Cake

More after the jump

Frozen Yeast Bank - Part 1

To go along with the last post on yeast starters I thought it would be a good idea to introduce the frozen yeast bank.  This is not only a good way to always have plenty of yeast strains on hand but is also a very good way to save money if you brew quite often.  A standard liquid yeast strain is around $8.00 USD and even then those should normally be grown up in a starter anyway.  This method allows you to purchase one of those liquid cultures and use it many times.  As a side benefit you can keep limited edition strains that are sometimes released on hand when they are no longer commercially available.  Lets start with the equipment required. Flyguy's Homebrew Talk Frozen Yeast Bank Thread thread is where I got a ton of information on how to do this and it's a great read.


Equipment:
-Small glass vials with a good sealing top that can be frozen and stand up to the heat of a pressure cooker (cynmar lab product 115-27910 is what I selected)
-Some pipettes (I got mine on amazon.com), the ones I purchased were graduated plastic 4ml
-Some food grade glycerine (also amazon.com)

Glass Vials from cynmar and the glycerine from amazon

-Something to hold the vials when they are in the pressure cooker, I used a beaker for most of these but you can also use several glass mason (canning) jars.

Vials staged in a beaker

-A pressure cooker, 15psi so that you can get up to 250°F is recommended. Read the instructions and follow them as these things can be very dangerous if used incorrectly.

-A small cooler and ice packs to go in your freezer.  A soft side small lunchbox sized cooler is a great option. This is to keep the yeast temperature stable during the auto defrost cycles most freezers have. (covered in part 2)

Optional (i.e. cheaper) Version - During each step in the process I'll  highlight a cheaper alternative if possible.  It likely won't be as clean (relatively speaking it will be the difference between sanitized and sterilized) but should work with the caveat that you will have a slightly higher chances of something going wrong due to an infection.

Procedure after the jump: