Yeast Storage

[the_yobbo]

Following on from the harvesting yeast thread http://www.aussiehomebrewer.com/forum//ind...view=getnewpost and Dan's recommendations about googling 'yeast slants' in that thread...

Well a google search and taking the first result gave this page
http://www.unm.edu/~draper/beer/slantuse.html

A couple of questions generated from reading the above link, which I assume contains common knowledge of those who do culture and store yeasts.
1) Are yeast slants a good way to go about storing yeasts?
2) Are there better ways of storing yeast?
3) It was recommended to reculture yeast slants stored longer than 3 months. Is there a storage method that has a longer shelf life?
4) Why slant the surface of the gelatin mix. If using test tubes, then slanting increases the surface area, but is it necessary for short/stubby vessels?

Cheers

 

[lukewarm]

I found this article linked, here possibly, a little while ago. It's pretty old, but it was the first time I'd seen it.

http://hbd.org/brewery/library/SterileDW1096.html

Seemed pretty good. Just waiting for my test tubes to arrive.

 

[Wolfy]

1) Yes, its easy, convenient and takes up little room in your fridge.
2) Yes, freezing and cryo are two.
3) Yes, see above (how do you think the yeast-banks do it), however slants should be viable at least a year maybe longer, even storing washed yeast-slurry under water in a stubby should be fine for a year maybe longer.
4) The slanted surface is so any moisture does not gather on the surface and contaminate your slant (when you make your first slants you'll see why this is important).

 

[kevin_smevin]

Following on from the harvesting yeast thread http://www.aussiehomebrewer.com/forum//ind...view=getnewpost and Dan's recommendations about googling 'yeast slants' in that thread...

Well a google search and taking the first result gave this page
http://www.unm.edu/~draper/beer/slantuse.html

A couple of questions generated from reading the above link, which I assume contains common knowledge of those who do culture and store yeasts.
1) Are yeast slants a good way to go about storing yeasts?
2) Are there better ways of storing yeast?
3) It was recommended to reculture yeast slants stored longer than 3 months. Is there a storage method that has a longer shelf life?
4) Why slant the surface of the gelatin mix. If using test tubes, then slanting increases the surface area, but is it necessary for short/stubby vessels?

Cheers

I was reading about yeast storage last night.

Storing in liquid nitrogen is the best for yeast stability and viability but obviously not an option for home brewewrs.

The best way is on slants. The method they recommend is this:

Always have 2 slants. 1 is for transfer purposed only (i'll explain later) and the other is for growing yeast cultures from. They should last 6 months in the fridge. After the 6 months you use the "transfer" tube and transfer yeast from this onto a agar/nutrient plate (cant remember what nutrients they recommend). Maintain this plate at 20-30 degrees C for 72hrs. Then inoculate your next 2 slants - 1 transfer slant and the other for growing up yeast. And it goes on and on. They did say there there is a significant chance of mutation during storage but it is still probably the best way of storing pure yeast cultures over time for home brewers.

This method has been used in breweries and research labs for ages. It works but not as good as liquid nitrogen or -80 degree freezers etc.

 

[unrealeous]

+1 for the sterile water. Slants need refrigerating.

 

[Bribie G]

For storage up to six months or so I find a good method is to just keep a couple of bottles of beer made on the chosen yeast, then culture them up just like Coopers bottled yeast. ATM I have a case of a Coopers kit brew made specially on a fresh vial of Proculture Wood Ale (aka 1469 and like hens teeth). Not the best beer of course, but drinkable. That's the thing, you actually get to drink the beer so nothing wasted. And in fact it is important to drink the beer because if the beer is good then the yeast is good.
After a few months the viable yeast count goes down, these bottles are now around five months so it will be interesting to see how they perform.