A few minutes maintenance every 3 days can make all the difference
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I am often asked how often should I backflush with cleaner (e.g. Puly Cafe) or should I do a clean water backflush every day. Well perhaps once every 2 Weeks to 1 month is sufficient to backflush with cleaner and of course don't forget to lubricate the cam after backflushing see e61-lubrication. Backflushing too often with cleaner is probably unnecessary and if you don't lubricate regularly could also result in premature wear of group head components. Backflushing with water after each shot can be done, but to be honest it's doesn't help hugely in the specific problem under discussion in this article.
The first point to get across is that backflushing (with or without cleaner) doesn't really clean the shower screen and group….it's main benefit is to clean the crap out of the vent pathway, the part where water shoots out at when you raise the lever to end the show, or on automatic machines when the shot ends and the group de-pressurises. I know, everyone will tell you that it does, but it really doesn't do very much for all the stuff behind the shower screen..I would guess that even if you backflushed with cleaner every week (don't) it still wouldn't prevent the build up behind the shower screen. Now of course I can't ask you to accept this without evidence….so here we go.
After the machine has been idle for a while (5 or 10 minutes), pull 1 oz of water water into a white cup…..it will probably look slightly brown. As you can see from the Photos. Try tasting the water…..it's probably not a good taste, as it cools down further it tastes even worse. If it tastes like that when you drink it, it's hardly likely to be improving the taste of your espresso or other coffee drinks!
OK lets have a look behind the shower screen and group and see what it looks like…Yuk!
So I replaced the screens and did a proper backflush with cleaner (Puly Cafe). As usual there was the satisfying heaps of brown foam from the vent tube and the usual brown crap from the group….it really looked like it was getting to the heart of the matter…..was it….lets see in the photo of water pulled from the group 5 minutes post cleaning:
So what was it doing….probably a fantastic job of cleaning the brew exit pathway, but we don't drink the water from that, or use it to make coffee. Our water passes into the group and into the space behind the shower screen….let's have another look behind there post cleaning, hmm….it hasn't done very much has it! Sure it will actually clean the chamber with the cams inside and our brew water does pass through that on it's way to the group, but that usually stays reasonable clean over a few weeks or so.
So now on to the 5 minute routine I am suggesting you follow every 3 days.
Drop the shower screen and with a Pallo Coffee Brush (as seen in the photo) or similar use a drop or two of washing up liquid and a tiny amount warm water on the (hopefully hot) shower screen. Scrub away at the inside/outside and very quickly it will look as new, rinse and set aside. Take the same brush and a drop of washing up liquid and scrub round the inside of the group and the dispersion disk…..they will come up like new (unless you've been very very naughty with the maintenance over a long period of time..Use a sponge cloth or similar to wipe away all traces of washing up liquid and replace the group gasket and shower screen. If like me you are lazy, the gasket will still be in place. Don't worry if it's a bit of a loose fit, this is because your gasket and shower screen will be cold (shrinks slightly) and the group will be hot (expands slightly), simply lock a portafilter in and once the shower screen is up to temp, it will be nice and snug. See shower-screen-and-group-gasket for instructions on how to remove and reinsert group. A bit of good news here, once you are removing the screen and gasket regularly, it will come out very easily and won't need lubrication each time you put it back. That advice is put there for people who might remove it once per year……yes they do exist and are more numerous than you might think.
It looks like this when it's clean and as you can see the water is clear and tastes good…..the bad news, you really need to do this every 3 days, but it's a small price to pay in time for the improvements it's going to bring to every shot you make on your machine. If you can, point others to this article because there are a lot of people who don't do this!
This advice has not been in this Wiki up until now because I was concerned that people might get the wrong end of the stick and start backflushing with cleaner each week, or simply become frightened about the whole process. If you have followed the Wiki and become competent with the maintenance routines, you will find doing this no problem and it's really easy to do, because once the screen and gasket is being removed every 3 days it's comes out really easy. Often newcomers to these machines find the whole process of screen and gasket removal daunting and wait 1 or 2 years until they are forced to do it because the gasket leaks….by then of course, it's a real bugger to get off and this makes them fear the task next time.