The brew unit brews, as the name suggests, but, just as importantly, it's also responsible for tamping ground coffee into a consistent puck. Inside the unit are two tracks which should be lubricated every six months or so for best results in the cup. Watch the video on the right to get the low down on food safe lubricant and how to keep the brew unit functioning smoothly.

Espresso Machine Maintenance -- How To Lubricate A Brew Unit