How do stove BTU’s work and how do you calculate what stove setting (e.g. 1,2,3 etc) is how many BTU’s?

Question

I have a presto pressure cooker that isn’t supposed to be used on anything higher than 12,000 BTU’s.

I’d like to use it outside, but it says to not use on any outdoor heat source because higher BTU’s. Case in point, I have a Coleman classic double stove that kicks out a MAXIMUM of 20,000 BTU’s.

I could buy something like this (https://www.jbtools.com/sportsman-series-sbcishd-single-burner-cast-iron-stove/?wi=off), which says max 8,500 BTU’s, but if I can get by with my Coleman, I’d rather just do that.

But I’m wondering how i’d go about figuring out what heat setting on the Coleman is 12,000 BTU’s?

In: 3

Answer 1

A BTU is a British Thermal Unit, an archaic unit of measure that represents the amount of energy needed to raise 1 pound of water by 1 degree Fahrenheit, when the water is at 39 degrees Fahrenheit.

When a burner says that it does 20,000 BTU, it actually means 20,000 BTU per hour. It’s an old-timey version of a proper unit for power – 20,000 BTU per hour is 5,861 watts.

Unfortunately it’s not very easy to measure. You could theoretically work it out with a scale, a stopwatch, and a thermometer, by heating a known mass of water for a known period of time and measuring the temperature change… but that gives you the heat that it transfers into the water, and doesn’t account for any heat lost to the air around the burner.