Ever since humans learned to create fire, we've been burning wood. It's an effective way to stay warm, cook food, and repel predators in the wilderness. However, simply throwing some logs on the campfire is far from the most efficient method of accomplishing these tasks. This is why we've moved from wood to energy-dense fossil fuels such as coal, natural gas, and various oil derivatives (kerosene, gasoline, diesel, and so on). The downside to these fossil fuels is that they're not as easy to obtain, and might become impossible to obtain in a long-term disaster scenario. Wood gas is an alternative biofuel that's simple to produce, even in an austere environment.

You may know about wood gas in the context of devices called gasifier stoves — the Solo Stove is one prominent example. These stoves use controlled airflow to produce wood gas, and immediately burn it to create a more powerful, cleaner-burning flame. But what if you want to save that fuel for later, and use it only as needed? YouTuber NightHawkInLight wondered this, and created a video that explains the principles of wood gas, as well as how to trap it without advanced tools.

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As described in the video above, wood gas can be produced by simply burning wood in an environment with limited oxygen. The wood can't combust, so it turns into charcoal — another extremely useful fuel. (This is the same principle used to make char cloth tinder.) At the same time, it gives off combustible gases through an exhaust tube. These gases contain water vapor, sap, and ash that forms a thick black tar which can be used as a sealant or glue. So, by generating wood gas, you're also able to simultaneously generate useful charcoal and tar — that's a win-win.

NightHawkInLight takes the experiment to the next level by trapping this wood gas in a way that pulls out the soot and other impurities. He does this by passing it through a tank of water and allowing the bubbles to rise into a sealed container, then waiting for the smoke to settle and the gas to turn clear. Submerging the tank then pressurizes the gas enough that it can be released through a valve as needed. It's certainly not as simple as grabbing a pre-filled propane tank before your next camping trip, but it's also free and nearly-unlimited, unlike commercially-refined fuels.

Written by Patrick McCarthy