This one area of commercial espresso machines operation in cafes, pubs and clubs that is frequently overlooked and very underestimated.
Most of our service calls are simply due a poor cleaning regime and or dirty machine / grinder.
There is a few things that guarantee you're serving the best coffee you can.
1. Great, fresh coffee beans. (not too fresh > 4 days, < 21 days) Custom Coffees can help you with that.
2. A pristine espresso machine. I cannot stress that aspect enough. If you seriously want good coffee, then you should back flush your machine with the appropriate chemical every day. Very busy, twice a day.
Failure to do so will mean the loss of delicate aromatics from the coffee, a slow build up of carbon in the machine (causing blockages), and a bitter flavour (especially present in the after-taste).
Why?
Once the coffee stops pouring in an espresso machine, pressurized water in the brewing group is exhausted back through the solenoid and into the drip tray, taking coffee oil with it.
The coffee oil burns on the hot metal surfaces of the pipes etc, and turns to carbon - tainting the flavour of the water used for subsequent coffees.
How?
1. Insert a blind filter or rubber disc into the group handle to prevent
water escape.
2. Put about 1/2 a teaspoon of back flush chemical on top of the blind filter or rubber.
3. Insert the handle into the group and push the button
(as though to pour a coffee). Once the handle is
pressurized (listen for the pump to go quiet, - about
5-10 seconds), push the button to stop pouring
(you’ll hear & see the chemical spitting into the drip
tray). Repeat switching on/off about 5-6 times.
4. Remove the handle & switch on again to rinse most of the
soapy chemical out of the group & handle. Re-insert the handle and repeat step 3 without the use of chemical.
5. Remove the blind disc and put coffee into the filter
basket as though to make a coffee.
6. Pour a coffee as you normally would but switch the button on & off throughout the pour (to get as much coffee oil back into the system as possible from one coffee portion).
Rinsing in this way is not enough to remove all traces of the chemical from the machine. Minute residues still remain & must be neutralised by re-introducing coffee (and it’s natural oil) into the system. Yes, this will dirty the machine again, but at least you have removed the buildup of old coffee oils.
Failure to do this within a short time of back flushing can result in damage to the solenoid by the chemical - see steps 5 & 6.
