1 1/2 teaspoon yeast (bread machine or quick)
4 cups warm water
3 cups all-purpose flour
4 teaspoons sugar
In a large glass bowl, mix the yeast into the warm water. Be sure it is the largest bowl you have. I had to go through three sizes of bowls before it stopped expanding and overflowing.
Be sure your water is not too hot, or it will kill the yeast. It should be between 105 and115 degrees F.
Stir in the the flour and sugar. Beat with a mixer until smooth. Cover loosely and let sit in the counter for a week (it will be bubbly and smell like a distillery). The layer of liquid that forms on the top and smells like alcohol is normal.
Move to a 2-quart or larger container and store in the fridge. I went through several different containers, but ended up with a small pitcher. Just make sure that whatever you pick is not metal.
Either use the starter once a week or stir in a teaspoon of sugar. If you use it, add 3/4 cup of flour and water as well as one teaspoon of sugar to replenish what you have used. Also, let it sit on the counter overnight after you do this. It should stay foamy and bubbly the whole time.
This is what a cup of the starter looks like after bringing to room temperature:
This is what it looks like straight out of the fridge before I feed it:
And this is what my loaf of bread from the oven looked like once sliced: