It takes about 540 peanuts to make a 12-ounce jar of peanut butter. By law, any product labeled “peanut butter” in the United States must be at least 90 percent peanuts. It takes fewer than 5 gallons of water to produce 1 ounce of peanuts. (Bonus fact: 1 ounce of almonds takes 80 gallons) The average peanut farm is 200 acres.