I agree you can make yeast live as long as you want but I was saying you cannot bring it back to life. If you really want to get into it I would suggest you cultivate a red, white and bread yeast. They all have different structures but will all survive in the fridge in small pots. You can add sugar to feed them each week and when they get too big throw some out or give it away. In the summer if you contact your local highways dept they will be only two pleased if you would come and remove new swarms of bees which hang on street signs and trees