Add grits, liquid, and salt to a medium saucepan off heat and stir. Let sit 5 minutes until the grits have settled to the bottom and the chaff has risen to the top. With a small, fine mesh strainer, skim chaff from liquid and discard.
Increase heat to medium-high and bring grits to a simmer while whisking gently but constantly until they have released enough starch so that the individual particles are suspended, about 5 minutes. Reduce heat to low, cover, and stir every 5 minutes or until grits (or polenta) are cooked, about an hour.
Whisk in butter and cover until ready to serve.
Despite their name, remember that grits cook to softness while polenta remains gritty. Food's funny sometimes.