Live Brewing Action (the series) continues with a wee video of the Ossian wort boiling for all its worth in the kettle.
We brewers are called thus for our habit of boiling. We've heard the expression 'putting on a brew' for boiling the kettle for a cup of tea or coffee, but in the brewer's world, putting on a brew means boiling the wort. We boil for several reasons - to sterilise the wort to avoid any off-tasting bacterial infections, to evaporate any excess water to reach the correct initial specific gravity for the beer, to extract the bittering resins and aromatic essential oils from the hops and to ensure clarity in the beer with a vigorous boil by clumping together unwanted protein hazes with hop tannins, which become the trub (hence trubble of the title) or sediment after the boil is finished.
The quality of the vid isn't that great but you can see that there's plenty going on in there.