Yes, you can mix it with 10-20% glycerol (final concentration) and freeze it solid, but in my experiments it still degrades over time (years) and freezing will kill some no matter what you do. A better solution is to add enough glycerol to depress the freezing point below the level of your freezer (about 0F) so that the mixture doesn't freeze solid, preventing die off. But unless you have a cheap supply of glycerol on hand, adding enough to make it 50% glycerol get expensive fast, especially if you are doing slurries as opposed to the 1.5 ml tubes I use.
Really the best solution for most people is to keep it under distilled water, as cold as possible but not frozen, and then make a starter when you're ready.
This assumes you don't want to play with agar, and you really insist on ranching vs. buying yeast.
Tom, I have a neighbor who is a retired biologist who has offered my a very large container of glycerin. He apparently used it for preserving bugs and stuff. Tell me, please, exactly how to use it for freezing yeast samples.
I trust with an amply and free supply, I can freeze fairly large samples which would help speed up the stepping up process.