In a medium saucepan bring 2 cups water and to a boil. Slowly add 1 cup long grain rice and, if desired, 1 tablespoon butter or margarine, and return to boiling. Reduce the heat and cover with a tight-fitting lid.
Cook about 45 minutes or until rice is tender and water is absorbed. Do not remove the lid during cooking since proper cooking relies on the development of steam inside the pan. Remove pan from heat and let stand, covered for 5 minutes. Fluff rice with a fork before serving.
Cooked brown rice can be stored, covered tightly, in a shallow container in the refrigerator for 4 days. It will maintain good quality in the freezer for 6 months.
After cooked rice has cooled in the refrigerator, transfer it to plastic freezer bags in quantities needed for future meals. Label with the date and quantity.