OK, so I'm getting carried away with this! But for anyone intersted in self-sufficiency being able to make bread is an almost necessity!! Anyway, being able to make yeast, I think, is an awesome skill and I'm going to try it (after I grow my hops vine, that is!!!)
http://www.thecookinginn.com/yeasta.html
(quote)
Homemade Yeast Cakes From Hops
1 double handful of hops *
2 med. Irish potatoes
3 pts. water
1 tbsp. sugar
3 tbsp. flour
Meal
* Use the blossom of the hop vine when it is just fully opened with the pollen still in it.
Tie the hops in cheese cloth; peel the potatoes; boil in the water until the potatoes are soft.
Discard the hops; mash the potatoes in the water; add the sugar and flour; set in a warm place until it foams. If you still have a cake of yeast from last making, add it after soaking. This hurries the fermentation; but given time the mix will work without yeast starter.
When it has worked until good and light, thicken with meal so that you can spread it on a board and cut it into cakes about twice as big as the store cake. Set them in a cool place to dry. Soften one in warm water and use it in bread just like any other yeast. Keep the cakes cool and dry until needed.
Replenish Hop Yeast Without Hops:
1 c. fresh buttermilk
1 cake hop yeast, softened
Flour to make a soft batter
Meal to make a soft dough
Batter the milk, yeast, and flour and set in a warm place by the fire. When it "works good" - gets frothy - thicken with meal and proceed as above. (end quote)