Flour and water can be mixed together to produce a thickener, a paste or a batter. The end result of mixing flour and water depends on the ratio of flour to water as well as on the temperature of the flour and the water.
Mixing one part water to two parts flour produces a paste that can be used for paper mache projects or even in place of glue. Adding 2 tablespoons of flour to 1/4 cup of cold water produces a thickener that increases the density of sauces, stews or gravies. Equal parts flour and ice water mixed together along with the yolk of an egg produce a tempura batter, which is a batter commonly used to fry food in Japanese cooking.