Yeast Slanting Questions - Expired Yeast and Cider

I am about to delve into the world of slanting yeast, because it sounds fun, and because saving money is fun.

Have a couple questions:

1. I have a bunch of expired yeast on its way, can I use it to slant? Should I make a starter first and slant from that? It was a great deal, so I am OK with not slanting from it, but there are some impossible to get strains in there too.
2. I make cider often, apple or cranberry, and would like to use some white labs cider yeast for this. It is very important that it be gluten free, so do you think I can use watered-down cider instead of wort in the slant tubes? I know I can make starters that way to build it up from the slant.
3. Basically the combo of the above two questions...can I use cider in a slant with expired cider yeast? Too much risk?

Thanks!

as to expired yeast, make a starter when you plan to use it. then innoculate at least 2 or 3 slant media (in case of infection or whatever) and go about the process the same. active, healthy cells will cover the entire surface of the slant in a few days vs a week if taken right out of the smack pack.

as to the slant media, yes you probably can. it only needs to have agar to thicken, sugars and nutrients for the yeast to survive. you might have to play with the ratio to get it to solidify.

i recommend always making a slant off of a healthy starter... i will never try to procreate direct from a smack pack again. use sterile loop and practices.

How long ago did the yeast expire? If it is really old I would make a starter. The dead yeast should flocculate early leaving only the healthy yeast to ferment the starter wort. I'd grab some of the actively fermenting yeast and streak in onto a plate, then grab a few healthy looking colonies from the plate and slant with them.

I think cider instead of wort should be fine.

Where did you get the expired yeast from?

Thanks guys, I figured this was the case, just wanted to confirm my thoughts.

toman8r said:

Where did you get the expired yeast from?

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Brewbrothers, in Portland, OR.

I think the cider slants will be OK (I made growth media out of salad dressing and agar in my lab) but put the cider yeast on a more conventional media as well. The cider slant may not have a good balance of nutrients (I know that slants are commonly made with minimal nutrients, but the correct balance is still important). This may mean that you get poor growth or other problems on your cider slant.
Having your yeast growing on a more conventional slant as well will serve as an insurance policy.

JoeJones said:

I think the cider slants will be OK (I made growth media out of salad dressing and agar in my lab) but put the cider yeast on a more conventional media as well. The cider slant may not have a good balance of nutrients (I know that slants are commonly made with minimal nutrients, but the correct balance is still important). This may mean that you get poor growth or other problems on your cider slant.
Having your yeast growing on a more conventional slant as well will serve as an insurance policy.

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The thing is, it doesn't really matter unless it is gluten free, and grown on gluten free ingredients, because I wouldn't use it.

Thanks for the input, and I think it is probably a good idea, but for $1-3, I can take the risk.

I could use sorghum LME instead I suppose...I will consider doing that.