Backflushing is an essential part of commercial espresso machine maintenance. In use your machine will develop a build up of Tannin and layers of oil produced from the ground coffee bean. These Tannin and oil deposits quickly dry and settle around the workings and components of the machine group head or group heads forming an unsightly, unhygienic and unwanted obstacle for the water of your machine to run over or through.
These elements have no mercy and stick to anything they come into contact with, the result is that your coffee will soon develop a bitter and undesirable tonal quality, not only affecting the taste of the espresso but also affecting the aroma, in extreme cases tannin deposits have been known to cause partial blockages to the path of the water before it hits the portafilter or filter holder. Tannin deposits are well known to be one of main causes for complaint of bitter tasting espresso.
However all is not lost as you can beat this problem with regular backflushing of the group head using PulyCaff Powder and a blind filter basket, so long as your machine has a 3 way solenoid (which all known commercial coffee machines do). Puly Back Flush Powder is the food-safe, high concentrate, fast dissolving product to use for best results.