Destructive distillation involves the use of primarily organic feedstock and is done in the absence of oxygen. It takes complex molecules and breaks them down into smaller pieces. Destructive distillation, particularly with organic feedstock, is capable of producing many products from a singular source. Wood, for example, will produce terp, terpentine, methanol, and a solid charcoal. Coal will produce coal tar and pitch. Fractional distillation, on the other hand, is the separation of a mixture of different substances, often by the use of their different boiling points. Substances whose boiling points differ by 25 degrees Celsius may be easily separated using fractional distillation. Fractional distillation is responsible for many of the fossil fuels we have in use today, each one possessing its own individual boiling point. So destructive distillation differs from fractional distillation in that it breaks down complex molecules into simpler forms, while fractional distillation simply separates what is already there.