Have you ever wondered why farting on a lighter causes a brief burst of flame? There's rarely any methane in farts, so what is it that causes some people's farts to ignite?

It was commonly believed that farts contain methane, which is why they smell and can ignite. This would be true... if people were cows.

There are certain kinds of gut bacteria which live in a certain percentage of the population, that do produce methane, but not in the majority of farts.

It really depends on what you put in your body. Egg, cauliflower, and meats are often more sulfur-rich, so they contribute a little hydrogen sulfide to the.. um.. release. As for the rest, the largest component is usually nitrogen, which makes up a good portion of the atmosphere, so it doesn't ignite all that readily.

It's mostly the hydrogen in the hydrogen sulfide that's released. So if the person does have the lucky gut that produces methane, it'll burn along with the hydrogen. To get the most flammable fart, people would generally have to eat sulfur-rich food.

There is so much more to farting than we know, but to get an idea of how an ignited fart looks like, watch the video below: