ascorbic acid for freezing yeast

What source do you use for ascorbic acid in your frozen yeast bank?

Jamil and White recommend 1 gram/L ascorbic acid to increase viability when freezing at -20°C, and I was wondering if I could use the ascorbic acid you would use for canning. It has other stuff in it, so does anyone know if these other things will affect yeast storage?

Thanks,


(I'll get a list of ingredients when I get up and check the label in the basement)

Ingredients: dextrose, ascorbic acid, citric acid, silicon dioxide (anti-caking)

Personally I think it's a waste of time to add it. They wrote up the "best case" in that book, but getting an extra point or two of viability isn't worth the effort of sourcing and adding it. You just need a few healthy, viable cells in that frozen sample to get your new slants going anyway.

It is vitamin c. Just get the powdered form at the grocery store vitamin section.