Esbit cubes are solid fuel cubes used for cooking backpacking meals. Weighing just 0.5 ounces (14 g) each, they’re ultralight, you don’t need a container to carry them like an isobutane gas canister or alcohol bottle, and you can even ship them via ground transportation (in the USA), making them ideal for post office resupply mail drops. Esbit will burn at any temperature or altitude, and you can even snuff out a cube when it’s half-used for use at a later time.
One of the major complaints about using Esbit cubes for backpacking is the time it takes to boil water. If you watch boil time tests on YouTube (get a life, seriously), people report 2 cup water boiling times of 8 minutes or more using a 14 gram Esbit fuel tablet.
But there’s a simple trick you can use to drop Esbit cube boil times under 5 minutes by increasing the surface area of a cube so that it burns faster. Simply break a cube in half along the center scored mark and stand the two halves upright underneath your cook pot. Voilà! This boils 2 cups of water much faster.
I learned this technique from Jon Fong, the owner of Flat Cat Stoves, and I’ve been using it all year with great success. I was sold on using Esbit before I learned this trick, but being able to boil water faster is icing on the cake.
Here’s the video by Jon where I first learned this technique. In it, he provides a detailed description of the tradeoffs between speed and efficiency when it comes to cooking with Esbit. I’d also encourage you to check out Jon’s free Backpacker’s Cookbook if you want to try Esbit baking using a very low simmering flame. It is fun to experiment with during the winter months when the days are short and the nights are long and you want a hobby for camp.