Attention Microbiology scientists or anyone who works in a lab

[bschot]

I am wanting 50mL centrifuge tubes to freeze yeast samples in and all I can find are really cheap ones that leak or good quality ones in cases of 500 that cost $300. I am only wanting like a 50 or 100. I'm open to ideas of a different container that would be freezable. I would prefer 100mL containers but I cannot seem to find any. I would also like to be able to autoclave them.

Thanks



Brian

 

[ColoHox]

If you pick up shipping (which shouldn't be much, CO to IL), I can send you some 50ml falcon tubes.

My mentor basically gave me everything when he shut down his lab.

 

[bschot]

That sounds awesome. I'm not sure how to send you the money I've never done anything like it before. Let me know how much I owe you.

Thank you very much.



-Brian

 

[ColoHox]

No problem. I think I have a flat rate box sitting around. I'll see how many tubes I can jam in there.

I'll PM you for your address and $$.

 

[bschot]

I appreciate it none the less. You wouldn't happen to know if I can use 2-propanol to control the freeze rate? The thread I read just said propanol and 1-propanol is somewhat difficult to procure and expensive.

Thanks in advance.



Brian

 

[PoppinCaps]

Just put the tubes in a bath of rubbing alcohol in the freezer for the first 24hours. Very close to mammalian culture protocol, if I understand what you're asking.

 

[ColoHox]

You can use any kind of alcohol to maintain cold temps. The best way to maintain viability is to store your cultures in a non-frost free freezer ( eg. doesn't cycle warm to melt the frost). 2-propanol is isopropyl alcohol, or rubbing alcohol, which is pretty easy to find.

 

[bschot]

I meant to ask does it matter which alcohol I use to control the descent to freeze the yeast in a controlled manner. The thread said it was important to freeze the yeast at 1°C/min because it helps maintain viability.

 

[BigPerm]

Isopropanol (ie, 2-propanol) is conventional and will work fine. If you add glycerol, you could freeze them without the alcohol buffering, but the choice is yours. If you plan to store for a long period, some glycerol is recommended.

 

[PoppinCaps]

I would add glycerol to 10-15% in the slurry either way, it's cheap and allows much more viability.

 

[passedpawn]

I would add glycerol to 10-15% in the slurry either way, it's cheap and allows much more viability.

Walmart carries glycerol in the health/beauty section. Not sure why, but I member something about fingernails. I froze a lot of yeast with water and 15% glycerol at one time.

Store in an insulated pouch or lunchbox to avoid problems with freezers that go through a defrost cycle. At least that's what I did and I seemed to have plenty of viable yeast when I used the vials later.

 

[BugHunter]

Walmart carries glycerol in the health/beauty section. Not sure why, but I member something about fingernails. I froze a lot of yeast with water and 15% glycerol at one time.

Store in an insulated pouch or lunchbox to avoid problems with freezers that go through a defrost cycle. At least that's what I did and I seemed to have plenty of viable yeast when I used the vials later.

I can't quite convince the wife to let me buy a -80*C culture freezer without freaking out, so my standard practice is something similar. I store my master cultures in small racked centrifuge tubes, in a modified YePD media (Malt Extract, Yeast Extract, Peptone, and Dextrose + 15% glycerol), and then store those in a small foam cooler with ice packs lining the floor before placing the whole assembly in my home chest freezer.

So far I've had no fermentation drift and and have good viability. I do propagate up from scrapings though (10ml, 50ml, 250ml, 1000ml, 2500ml), so my method isn't the fastest since I'm mostly focused on yeast research and not actually brewing more than the necessary, "Yep, that makes a tasty beer" experimentation.