Originally Posted by dave the baker
That's a very good starter. One suggestion that really works: After the starter is going, I use a (cheap, like from a motel) plastic shower cap over the crock. It allows the excess gas to escape and is so much easier than fooling around with the cheesecloth every time you feed or use it. Warning, Beginners: Never, ever cap your starter tight! It can, and will, pop or explode all over. And it's one heck of a mess to clean up!
You can use a lot of different liquid mediums for starters: whey, potato water, fruit skins liquified. I get good results and do not use yeast.