Guide to Making a Frozen Yeast Bank - Page 62

mthompson · 02-02-2012, 05:03 PM

Quote:

Originally Posted by Zamial

I get mine here: http://www.cynmar.com/ProductDetail/11527908_Clear-Glass-Vials-Wautoclavable-Cap-16ml--12pk they are completely reusable and autoclavable including the caps.

Same vials I got...three 12-packs, two 10mL pipettes and some stir bars got me over the $25 limit.

postal_penguin · 02-02-2012, 07:17 PM

Quote:

Originally Posted by mthompson

I thought about using those, but I've seen a lot of those plastic centrifuge tubes melt or deform in an autoclave.

I've never seen those tubes melt. They go through the autoclave at my work fine which runs at a higher temperature than my pressure cooker can attain. Just make sure to not screw them tightly or they will explode or collapse during cooling.

mthompson · 02-02-2012, 07:23 PM

Quote:

Originally Posted by postal_penguin

I've never seen those tubes melt. They go through the autoclave at my work fine which runs at a higher temperature than my pressure cooker can attain. Just make sure to not screw them tightly or they will explode or collapse during cooling.

I should clarify, I have seen the 50 mL disposable centrifuge tubes melt a bit in a lab autoclave....since then I assume they might all melt. It wasn't exploded or crushed, the part of the tube above the liquid inside was melted and sloughed to one side.

I have some here at work that are 15mL...I'll throw some in my pressure canner and see if they make it through.

mthompson · 02-04-2012, 03:30 PM

I am not sure if anyone has trouble resuspending their vials, but I did. It took more than 10min of shaking to get it halfway their. So adequate a vortex mixer using an orbital sander.

First I tried just the sander alone, which worked so-so. I had to hold the vial pretty hard against the sander and tilt it just a bit to get a vortex. Next, I placed the silicone jar opener on the sander. This worked much better, but the vial ate right through the silicone because of the pressure.

I then took the four srews out holding the sander platform on the bearing. I cut some plywood to the size, drilled holes for longer screws in the factory hole positions, drilled holes for the vials... And used the short factory screws as anchor points for the rubber band stabilizers.

Before:

Installed:

30 seconds after:

She ain't gonna win a beauty pageant, but she sure mixes year vials well.

postal_penguin · 02-04-2012, 04:05 PM

Quote:

Originally Posted by mthompson

I should clarify, I have seen the 50 mL disposable centrifuge tubes melt a bit in a lab autoclave....since then I assume they might all melt. It wasn't exploded or crushed, the part of the tube above the liquid inside was melted and sloughed to one side.

I have some here at work that are 15mL...I'll throw some in my pressure canner and see if they make it through.

Weird. I autoclave the 50mL tubes after they have been used too since we get them already sterile.

I just used my pressure cooker on about 50 of the 15mL tubes with 3-4mL of glycerol and they all survived except one which I closed too tightly and it collapsed when it cooled.

Also, do you have problems with the vials cracking if you fill them all the way up and then freeze? Seems the ice would expand and break the glass.

**Nightbiker** · 02-06-2012, 12:21 AM

never had a problem getting my yeast back into suspension. When I take one from the frozen 'bank', I put it in the fridge a day before use, then on the day I'm going to use it (to make the starter) I take it out of the fridge so it achieves room temperature while I make the starter wort, then by the time my wort is cooled, the vial is 'warm' and a brief shake puts everything where it needs to be.
Sometimes (if I have a large enough sample -I use a smaller test-tube-like plastic vial for long-term samples, but also store a larger amount in a sterile sample container (from my work place) -it is a 120ml container that seals and seems to survive freezing with no ill effects -when I get 'em, they're sterile as long as the paper tape seal hasn't been broken) -these are USUALLY used for urine samples (either drug testing or to obtain a culture) -so in a way, I'm kind of using them for PRE-urine samples (grin). Anyway, I've been just defrosting THOSE like above, and pitching it directly to the wort with good results.

mthompson · 02-06-2012, 12:26 PM

Quote:

Originally Posted by postal_penguin

Also, do you have problems with the vials cracking if you fill them all the way up and then freeze? Seems the ice would expand and break the glass.

No breaking yet. Most of the vials are not even frozen. Some are a little slushy, but still air travels through if I tilt them.

Quote:

Originally Posted by Nightbiker

never had a problem getting my yeast back into suspension.

I think mine just lack enough headspace to get a good shake going on. Plus, my yeast layer is 3/4" thick when it settles out. They definitely need more agitation than I can manually provide.

bjohnson29 · 02-15-2012, 03:29 PM

I notice that after a day or two in the freezer, that my samples begin to separate (30% glycerin, 60% yeast, 10% headspace)...this normal?

mthompson · 02-15-2012, 10:58 PM

Quote:

Originally Posted by bjohnson29

I notice that after a day or two in the freezer, that my samples begin to separate (30% glycerin, 60% yeast, 10% headspace)...this normal?

Normal. The glycerin probably won't freeze, so separation is inevitable. The yeast will already be dormant as long as you store them in the fridge for a day or two before putting them in the freezer.

ekjohns · 02-15-2012, 11:46 PM

The 15 mil falcon brand don't fully melt but they do lose their shape in our autoclave.

As far as the yeast slurry none of mine settle out in layers. Why are they not freezing in a few hours time? You only need 20-25% glycerol and mine always freeze fine. The yeast may start to settle but 25% glycerol should stay as a homogeneous mixture