Back flushing 101

With the exception of Lever machines, regular back flushing is a vital part of any machine's maintenance schedule. Not only will it prolong the life of your machine, but it will also prevent the buildup of rancid coffee oils that will make your espresso taste bitter and acrid.

While everyone's needs may vary slightly, I recommend that machines making less than five shots a day be back flushed with detergent every two weeks. If you're using a particularly dark roast, then you ought to instead back flush with detergent every single week, since the oils will accumulate more quickly.  If you're making more than 10 shots a day, Just jump straight to back flushing with detergent every week. I also recommend that you back flush daily without detergent. Doing so right after your last shot of the day will help to keep some of the oils from adhering to the shower screen to begin with. The detergent you use is important enough that it could damage your machine if you use the incorrect detergent. In such a case, we would not cover the resulting repair under warranty.

Unless your machine calls for a specific product to be used, such as certain UNIC machines, or a Slayer, we recommend this detergent for home and commercial use. Not only can it be used for back flushing, but it's also perfect for use in cleaning your portafilters. It's not so aggressive that it will damage the rubber gasket materials in your machine, yet it is efficient enough to readily dissolve accumulated coffee oils. 

Possible signs that your machine may need to be back flushed include:

  • A constant small leak of water through the brew valve exhaust
  • A portafilter that's hard to remove, in combination with a release of pressure from the portafilter when it is removed
  • Slower than normal flow through the group, even though your brew gauge shows the same pressure as normal

Now that you know that you have to back flush, follow the steps below to learn how to do so.

  1. Take out the regular coffee basket from the portafilter
  2. Add the blind basket to the portafilter (or the rubber stopper, depending upon the brand of your machine)
  3. Dose out 1/2 teaspoon of cleaning detergent into the blind basket
  4. Put the portafilter into the group
  5. Use the manual button to start the pump, or lift the brew lever
  6. Wait ten seconds
  7. Press the manual button again to stop brewing
  8. Wait ten seconds
  9. Without removing the portafilter, repeat steps 5-8, four times
  10. Remove the portafilter from the group
  11. Press the manual button to start the pump
  12. Wash the blank basket in the stream of water until no detergent remains
  13. Once again put the portafilter into the group, without any detergent this time
  14. Repeat steps 5-8, five times
  15. Remove the portafilter from the group
  16. Remove the blank basket
  17. Install your normal brew basket  

It's important to follow these steps as closely as possible. If you skip some of the rinsing cycle, you run the risk of having some of the dissolved cleaner precipitate out solution to clog the brew valve--thereby by causing the same issue you might have been trying to resolve by back flushing in the first place. You can cause the same exact issue by adding too much detergent.

Have you just finished back flushing, only to find that the brew lever on your E61 machine is squeaking? Not to worry, that's perfectly normal. The detergent we recommend will also slightly break down the DOW111 lubricant used on the cam lever shaft. As a side-note, this is another reason why it's important to back flush daily without detergent--it reduces the coffee oil buildup without excessively removing the lubricant. If you move the cam lever gasket up and down a number of times, it will redistribute the lubricant and the lever will start to move smoothly again. If it doesn't, or if the brew lever doesn't stay in the upright position unless you hold it there, then it's time for you to replace and re-lubricate your cam lever gaskets.