Well, I don't buy much yeast anymore, unless I want a different yeast from what I brewed with. What I do now is just boil up some DME or wort I canned. I put it in a 12 ox bottle (just under half full). Then I go get a bottle of my homebrew (one fermented with the desired yeast). I pour the top 10 oz. into a clean pilsner glass (for me to drink). Then I clean the rim of the bottle with vodka and swirl the remaining 2 oz. of beer in the bottle to suspend all the yeast trub and then pour it into the sanitized 12 oz. bottle half full of wort. I then affix a bubbler. When I see a little activity I then add wort in gallon jug up to a pint, then when it is active up to a quart, then up to 1/2 gallon. And, now I have a
1/2 gallon of starter for 10 gallons of brew. The whole process does take about 5 days. I normally start on a Monday and brew the following Saturday.Anybody else do this regularly. It saved over $5 each batch.