Lawrence Brewers Guild

I've also seen it suggested to put the frozen yeast vials into a container with PGA (Everclear) and place that inside a small
(six pack size) cooler inside the freezer to protect it from the defrost cycle.
I thought about freezing, but seems like slants are much less trouble. Just need to re-plate every 6-12 months, I think.
jim

I have Petri dishes, slants and froze. The frozen is a bit more convenient, pull it out of the freezer, add it to 250ml starter for 2 days then to 800ml, 2 days and pitch.

The way I freeze yeast is:
- add glycerin to vial (final concentration will be 30% v/v)
- Autoclave and cool vials.
- Add appropriate amount of yeast slurry to get 30% glycerin (v/v)
- Mix and put in the refrigerator for 2 days
- Place in a Styrofoam box on its side in a "non freezable pack" sandwich.








I have had an Irish Ale in the freezer for about a year and just brewed with it, worked great.

Jason

Nothing gets by the Squirrel Bucket! You remind me so much of myself 10yrs ago its not even funny. Sicko!

Btw, this is an excellent thread Chris and Jason, very nice work.

I inoculate 20 ml wort with a loopful of yeast from a slant, 2 days step up to 200 ml, then to 2-3 L for 2-3 days, crash, decant spent beer and pitch. Takes a couple days longer than your method, so I've gotta plan ahead some.

Hey Andy, did you ever get over it?

jim

Jason,

You might want this to go along with your bank:
http://www.mrmalty.com/yeast.htm

JMcG wrote: Hey Andy, did you ever get over it?

jim

I sold alot which bank rolled my electronics with the majority of it. I still have to much crap tho. Just cant seem to part with the rest of it.

Chris that chart is AWESOME!!! Thanks

Andy it is no wonder you don't have even more stuff, you have an awesome setup. What I would give to have 1/2 of your shop...

Does frozen keep them safe or any other else make them better safe?

I have slants and plates in the fridge, slants in the freezer. I have been gone over a year now and some of these samples are about 2 years old. So I have not been paying much attention to my yeast bank since last year.

When I was home for Xmas, I took a look at the frozen and yest in the fridge...all 32 strains were doing great. Some will have to be re-plated within the next 6 months or so (the media is shrinking from the side) but they all looked viable (no bugs).

The biggest issue with putting up yeast for long term storage (chime in on this Chris) is your sterile technique. Clean yeast is happy yeast. You have to be almost fanatical about your sterile field when you put up the yeast, but if you do, you will have yeast that will last a very long time.

One suggestion is to put up a "reference" and a couple of "working" samples for each yeast strain. When you grow the yeast for a batch of beer, you take the loop sample from the working slant. If you happen to contaminate the slant, you have backup. I do my "mother" strain on plates and my "working" on slants.

Jason

Started growing a starter on Friday from a slant I inoculated 3/11. Took 3 days to "wake up" and start fermenting in the 20 ml baby starter tube, but went to high krausen in less than 12 hrs in the next, 300 ml, step.
I'll divide it into 2 and go to two 1500 ml tomorrow. Should be ready to pitch Friday (I probably won't brew til Sunday, just put the flasks in the fridge and pitch the sludge). Total time elapsed 1 week.
Point is, you should re-plate (re-culture) your yeast every 6 months to keep it fresh and get quicker results. Fresher samples can be ready to step up in 1-2 days usually, pitch strength in 4-5 days.
I have also kept baby starters of wort/yeast in the fridge for several weeks, and they will build more quickly (pitch strength in 3-4 days).

Jason, good to have you back posting. Look forward to seeing you in the next month or two.

jim

Jim,

I have records for a bunch of the strains from 10ul loop from slant to 2L pitch rate, with cell counts (I have a microscope) over the time I was brewing regularly. I will be conducting the same type of experiments/observations when I fire up again. It will be interesting to see how much change in the propagation speed and cell count over time with the 2 year old plates. I will definitively post the results.

I would love to re-plate the yeast bank every 6 month or so...but as the yeast library gets bigger, it is a lot of work.

If you plan ahead and give the yeast some time to "wake up", about a week to get to pitching rate, i have found things go very well.

One of the things I found really helped was buying a very small stir bar which would fit in my 30 ml viles. I have done a side by side with a 10ul loop in 20 ml of 1040 SG start...one was with micro stir bar, one without. The difference in the speed was amazing (I did not have a microscope at the time, so I don't have cell counts for this experiment...I smell a redo). The continually stirred vial was ready for step up in less than 24 hours at room temp vs 48 hr for the non-stirred vial (just shaken if and when I walked by).

It will be very good to be home and look forward to seeing everyone at the meetings.

Jason

Mini stir bar sounds cool. Should double growth rate in the initial stage.
jim

They are cheap and very easy to lose...very tiny. I use a rare earth magnet from an old hard drive to "hold" the stir bar when I transfer the starter out of the vile.





Jason