The Boil Kettle is just that: a kettle to boil the wort in. It's fired by a forced-air gas burner that does its job very nicely. Hops (a type of flower) are added to the sweet barley wort during the boil to add bitterness, a green flavor, and aroma. At the end of the boil, bitter wort is re-circulated into the kettle such that it spins clock-wise in the kettle. This makes the particulate matter (denatured proteins and hop particles) form a cone in the center of the kettle so that we do not pull the goo off into the fermenter.