The Float Test is a common method used to determine if a sourdough starter or leaven is ready to use. It involves dropping a teaspoon of starter into a glass of water; if it floats, it is deemed "ripe."

Hooch is a colloquial term for the liquid layer (ranging from clear to grey or black) that accumulates on top of a neglected sourdough starter. Biologically, it is primarily ethanol (alcohol) produced by wild yeast during fermentation.