Cook times are going to vary. Because briskets can weigh between 12 and 22 pounds, times can range from 8 to 16 hours depending on size, temperature, and the specific brisket. No two animals are the same. Our general rule of thumb is to plan on between 30 and 60 minutes per pound. For example, a 16-pound brisket cooked at 275 degrees Fahrenheit will take between 10 and 12 hours. The entire process from trimming, injection, seasoning, and cooking will take between 18 and 20 hours. Give yourself enough time. This is a “good things come to those who wait” kind of deal, but rest assured … you’ll be glad you did.