To make a basic polenta you need 4 cups of water for each cup of cornmeal and salt. Bring the salted water to a boil and add the cornmeal in a thin stream while stirring constantly to prevent lumps. Once all the cornmeal is in the pan, reduce the heat to low and continue stirring every 5 minutes until the polenta is cooked, 20 to 30 minutes.
As per Joyce Goldstein,” whisking together the cold water, salt and cornmeal, bringing it to a gradual boil over medium heat, and then whisking from time to time as it cooks, is foolproof, producing lump-free polenta. As soon as it boils, reduce the heat to low and simmer it, stirring often, until the polenta is creamy, rather than grainy, on the tongue.”