Here's my simmer burner in action. My stove burns 1oz of fuel in 6 - 7 min. I had a full boil around 3:30 and at a little over 4:00 I put the simemr burner on. I estimate I had about 1/3oz of fuel left, and it contiuned to simmer for 18min, a total burn time from lighting of 22min and change.