Cartridges have a built-in wire-coil, similar to one found in a light bulb. This wire-coil heats up to vaporize e-liquid. The unpleasant burnt taste is often a sign that there is a lack of e-liquid in the wire-coil. If your cartridge is new, take two long draws from the E-Cigarette to bring the nicotine into the coil. If you experience this taste after using your cartridge for some time, it’s likely time to change your cartridge and dispose of the used one properly.