Something happened this week, I honestly cannot remember what, that reminded me of an instance that occurred some years ago regarding espresso machine cleaning. I had asked a barista I was visiting to demonstrate her cleaning technique to me. She proceeded to lift a dirty old rag and, with pride (!!?), polished the steel panels until they gleamed. Ok, she was not only new to the country but new to the industry. However this is not the sad part. When the shop owner passed by he berated the unfortunate girl for missing a spot! Now this guy had been trained by both myself and his GREENBEAN sales rep on numerous occasions and had obviously missed the whole point of both the workings of an espresso machine and the need to treat fine (for fine think “non- burnt”) coffee with proper respect.

As I thought about it, it began to dawn on me that after 25 years roasting coffee I had forgotten that, in this country at least, most people are used to brewing quality teas not quality coffees. So, for those of you interested, here are some facts (Note: This relates just as much to home machines)

  • An espresso machine brews coffee by passing hot water through the coffee at a pressure of about 9 bar. This is a very high pressure, certainly too high to remove the handle safely (if at all) after the brew is finished. To counteract this, the machine releases the pressure automatically by way of a solenoid valve.
  • As the pressure releases some of the coffee brew “rushes” back through the narrow tubes in the hot brass group. This happens every time an espresso is made.
  • When an espresso machine is cleaned properly, a detergent mix (please, NOT Milton. Use a food -quality detergent available from all good coffee companies) is forced through the tubes by way of the solenoid valve. This cleans the coffee oils before they have a chance to become stale and rancid.

Cleaning with detergent should be performed at least daily and preferably last thing at night (Don’t allow coffee oils to dwell in the tubes overnight). Do this and I guarantee 95% of your coffee related issues will have been resolved.