I use 1 and three-quarters cup of water to 1 cup of rinsed quinoa. If you want a little softer mushier quinoa, you can add a little bit more water. While most people say 1 cup of quinoa to 2 cups of water, rinsing the quinoa first means that you don't always get rid of the excess water, so reducing the cooking amount means that you reduce the risk of mushy grains.