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

Cascadian Dark Ale

Cascadian Dark Ale

American IPA

Type: All Grain	Date: 3/10/2012
Batch Size (fermenter): 10.00 gal	Brewer: Chris Vaught
Boil Size: 12.44 gal	Asst Brewer:
Boil Time: 60 min	Equipment: Keggle and Cooler
End of Boil Volume 11.44 gal	Brewhouse Efficiency: 72.00 %
Final Bottling Volume: 10.00 gal	Est Mash Efficiency 75.2 %
Fermentation: Ale, Two Stage	Taste Rating(out of 50): 45.0
Taste Notes:
Ingredients
Ingredients Amt Name Type # %/IBU 25 lbs Golden Promise (2.0 SRM) Grain 1 86.2 % 2 lbs Caramel/Crystal Malt -120L (120.0 SRM) Grain 2 6.9 % 1.00 oz Magnum [12.00 %] - First Wort 60.0 min Hop 3 20.8 IBUs 1.50 oz Magnum [12.00 %] - Boil 60.0 min Hop 4 28.4 IBUs 1.00 oz Cascade [4.90 %] - Boil 60.0 min Hop 5 7.7 IBUs 1.00 oz Cascade [4.90 %] - Boil 30.0 min Hop 6 5.9 IBUs 1.00 oz Cascade [4.90 %] - Boil 15.0 min Hop 7 3.8 IBUs 1.00 oz Cascade [4.90 %] - Aroma Steep 5.0 min Hop 8 0.0 IBUs 1.0 pkg California Ale (White Labs #WLP001) [35.49 ml] Yeast 9 - 2 lbs Black (Patent) Malt (500.0 SRM) Grain 10 6.9 % 1.00 oz Cascade [5.50 %] - Dry Hop 4.0 Days Hop 11 0.0 IBUs
Beer Profile
Est Original Gravity: 1.071 SG	Measured Original Gravity: 1.046 SG
Est Final Gravity: 1.011 SG	Measured Final Gravity: 1.010 SG
Estimated Alcohol by Vol: 7.9 %	Actual Alcohol by Vol: 4.7 %
Bitterness: 66.6 IBUs	Calories: 151.6 kcal/12oz
Est Color: 39.2 SRM
Mash Profile
Mash Name: Single Infusion, Light Body, Batch Sparge	Total Grain Weight: 29 lbs
Sparge Water: 7.24 gal	Grain Temperature: 72.0 F
Sparge Temperature: 168.0 F	Tun Temperature: 72.0 F
Adjust Temp for Equipment: FALSE	Mash PH: 5.20
Mash Steps Name Description Step Temperature Step Time Mash In Add 33.75 qt of water at 159.1 F 148.0 F 75 min
Sparge Step: Batch sparge with 3 steps (Drain mash tun, , 3.62gal, 3.62gal) of 168.0 F water
Mash Notes: Simple single infusion mash for use with most modern well modified grains (about 95% of the time).
Carbonation and Storage
Carbonation Type: Bottle	Volumes of CO2: 2.3
Pressure/Weight: 12.08 oz	Carbonation Used: Bottle with 12.08 oz Dry Malt Extract
Keg/Bottling Temperature: 70.0 F	Age for: 30.00 days
Fermentation: Ale, Two Stage	Storage Temperature: 65.0 F
Notes
Created with BeerSmith

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:

Yeast Starters

Good pitch rates with healthy yeast is one of the biggest steps anyone can take to making better beer.  The Mr. Malty site has a pitch rate calculator and tons of information on using yeast well.  This post will  cover making a starter for a batch done a few weeks ago from an old smack pack of yeast.


1.  Prepare some wort, I use dried malt extract (DME) in a concentration that will come pretty close to matching the design of the beer, 1.040 in this case.  Simply measure (by weight if you can, and you should be) your DME for the volume of the starter you plan on making and bring it to a boil  on the stove for a few minutes.  Hops are not needed here.

2.  Cool your wort down to pitching temperatures, I aim for below 70 °F for ales.  Just like your actual batch of beer make sure everything that touches the wort or yeast from here on out is sanitized.

Cooling the Wort in a Small Ice Bath

Flask Full of Start-San