Distillation Unit process that works a little like a still. Instead of removing contaminants from your water, a distiller reverses the equation and removes the water from your contaminants. Specifically, this countertop machine — which resembles what you'd expect to see if a hot-air popcorn popper and a pressure cooker ever mated and produced offspring — heats water to the boiling point, traps the rising steam, and uses an electric fan or other cooling device to condense the vapor into liquid again, minus the contaminants.