The controlled burning of oak, mesquite, and other wood types produces smoke, which manufacturers condense and reconstitute in water. The process is known as deconstructive distillation.
Naturally derived colouring plays a critical role in broadening the visual spectrum of possibilities for liquid smoke.
Liquid smokes are typically in the range of pH 2 to 3. Liquid smoke uses colouring with stability at pH 3.0 or less.