Yeast Bank Implementation

Hey guys,

I've read the previous thread on the yeast bank planning, and I've talked about taking the lead on implementing a bank with plates. I've already been working on a plan. I've already started tackling this a little bit. I will start a google spreadsheet and post it in this thread, or in this forum if anybody has the capability of doing cell counts and would like to pitch in on collecting some data. If so, we'll meet and discuss to standardize methods and materials, which I believe to be important for a somewhat scientific approach.

The procedure below is complete for those who want to do everything themselves at home. I have prepared many plates and have a few strains growing on plates at the house. Most people will start at step 5.

Purpose

The goal of this study is to determine the optimal time, equipment, and environmental conditions to grow a yeast pitch with various strains and to create a reference for the CHAOS homebrewing club for this topic.

Materials

• Required

  • 500mL borosilicate Erlenmeyer flask

  • 2000mL borosilicate Erlenmeyer flask

  • 5000mL borosilicate Erlenmeyer flask

  • Pressure cooker

  • Aluminum foil

  • Parafilm

  • Light DME

  • Nichrome inoculation loop

  • Butane/propane torch, or Bunsen burner

  • Sterile transfer pipettes (autoclavable or disposable)

• Optional, or I can provide

  • Stir plate and bar

  • 100x15 mm petri plates

  • Agar agar

  • Microscope

  • Hemocytometer

• Documents provided online

  • Google Docs note sheet

    • http://bit.ly/CHAOSYeastNotes

  • Google Docs note submission form

    • http://goo.gl/forms/xnQW9ou13U

  • Google Docs spreadsheet for results

Method

This is stepwise from yeast selection to final pitching volume.

1. Prepare solid media

   1. Dissolve DME at a rate of 100g/1000mL (1.040 starter wort)

   2. Heat and dissolve agar agar into above solution at a rate of 17g per 1000mL

   3. Put in Erlenmeyer flask and cover with foil, place in pressure cooker filling water just below the level filled in the flask

   4. Close and boil for 15 minutes, cool to equalize

2. Pour petri plates

   1. While performing step 1d, ready 20-25 plates closed and face up

   2. Pour media into each plate so it barely covers the bottom and cover

   3. Wrap edge of lid with parafilm and place in the refrigerator

3. Collect yeast sample (from dreg or pack)

   1. Flame opener and bottle lip

   2. Decant beer, resuspend dreg

   3. Dump onto plate

   4. Parafilm and leave out to allow yeast to grow, label with the following info

      1. “Capture Plate”

      2. Beer Name or Yeast Identifier (eg. Rogue Dead Guy, or WY1056)

      3. Today’s date

4. Streak for isolation

   1. Flame your inoculation loop until it glows red, allow it to cool for a few seconds

   2. Pick up some of the yeast from the plate in step 2 and streak it near the edge of a new plate

   3. Flame the loop, rotate the plate 45 degrees, drag a streak through previous streak once or twice, and continue to streak without touching the previous for a few more iterations

   4. Repeat C until the entire area of the plate has been used

   5. Parafilm and leave the plate out for a few days to allow yeast to grow, label with following info

      1. “Isolation Plate”

      2. Beer Name or Yeast Identifier (eg. Bell’s Hoplsam, or WLP004)

      3. Today’s date

5. Prepare liquid media

   1. Repeat the procedure for solid media, but leave out step 1b (agar agar)

6. Select single colony and streak a lawn on a new plate and leave out. Save all 3 plates produced by this process. This yeast is now banked.

7. Flame loop, pick up as much yeast as possible, and inoculate 200mL flask, replace foil and place on stir plate with sanitized stir bar

8. Grow for X days, record that number, record ambient temperature each day

9. Take sample with a sanitized or sterile pipette, dilute and count using hemocytometer, record cells/mL

   1. I will write a separate document on this topic as the procedure is fairly complex for those who are not familiar.

   2. Also note if you see bacteria, but no need to count. Should be obvious in tasting the supernatant of the next step up.

10. Pitch entire slurry into 2000mL of liquid media

11. repeat steps 6 & 7 above

12. Chill, decant and taste, resuspend, and pitch into either 2000mL or 5000mL of liquid media

    1. Ideally you should take notes on flocculation, aroma, and flavors

13. repeat steps 6 & 7 above

14. Chill, decant and taste, and pitch into 5 gallons of beer and treat like it’s a normal brew

    1. Note flocculation, aroma, and flavors again

15. Share the final product!

Optional Steps for the Ambitious

• Oxygenate each step-up starter before pitching

  • Record which steps were oxygenated and for how long at what flow rate

Please record all of your results by filling out the Google Doc note sheet as completely as possible and submit using the Google Form. This will enter it into a spreadsheet for easy data management.

I don’t want this to be exclusive. I would like as many members to participate as are willing. This will lead to some limitations

Expected Limitations

• Lack of standardized equipment and techniques leading to varying numbers

• Low number of data points