E61 Group Maintenance

This month we are going to take a look at the ever popular E61 style brew group. This group can be found on many machines today and is a very temperature stable brew group, thus its popularity. Introduced by Faema in 1961 on the E61 machine, this group head revolutionized the espresso industry by providing a thermically stable method of espresso preparation.

Today the E61 group or versions of it can be found on several brands of machines and still manages to be one of the best groups available. This is a case of technology being way ahead of its self I suppose, and the fact that “If it’s not broke don’t fix it”.

The E61 group is a massive chunk of brass, when assembled and ready to place on a machine it weighs in at 9 lbs. This weight mass contributes to its ability to maintain a consistent temperature. The other function that helps with this temp stability is the thermo syphon function; this is a function of water circulation that reduces hot spots within the group head. A very simple system that is worth its weight in creama.

This article is part one of a series of articles based on the E61 group head. As so many manufacturers use this style of group, I find that there are still Baristas out there that do not know how to properly maintain the screen and baskets. The maintenance procedure is quite simple and if kept up your espresso machine will last many years.

The first part of maintaining this style of group is to understand the idea behind back flushing. Back flushing an espresso machine is a process that involves forcing water and a detergent back through the group all the way to the three way valve. This procedure starts by replacing the filter basket in the portafilter with what is referred to as a blind filter or a back flush disc. This blind filter has no filter holes thus allowing the group to build pressure and force the cleaning product back through the group. The manufacturers of these products provide information on the quantities of the product to use. Make sure that you stick to the prescribed amount, never use more than suggested as this can create trouble.

This is the blind filter or back flush disc as it is also known. Note the lack of holes in this filter.

The big brass screw. This is the diffusion screw and or disc. Make sure that you clean the oil residue from this as well.

The portafilter or filter handles of your espresso machine fit into the group and are sealed by way of a rubber gasket. After a period of time the gaskets can become hard and do not seal well. If you notice that water is leaking around the group where the filter resides, it is time for gasket replacement. The gaskets need to be replaced on a quarterly schedule, and if you decide to operate on a longer schedule you may find you need to chisel them out. Gaskets not maintained, are very difficult to remove as well. The rubber has a tendency to carbonize and turn very hard. Maintaining these gaskets on a regular schedule will make your life easier.

This image shows the condition of a gasket that is ready to replace. Note the groove, this is many times the cause of leaks.

These are the old parts removed from the group. In this case we have opted to replace the screens as well.

The new parts ready to install.

Removal of the gasket is very simple and involves the use of an ice pick or a scratch awl. These devices will help you remove the gasket without much effort. Simply pry the gasket out. When you do this the group screen will follow as the gasket holds the screen in place.

This is where all the action takes place. You will be spending a little time with this view. Take your time and get it all clean.

Use a scratch awl or an ice pick to remove the gasket. The gasket holds the screen in place , so it will all come down together.

Now with the gasket removed and the screen in your hand, take a look at the screen. Hold it up to a light to inspect for holes larger than the screen it is made from and also look for coffee build up. You want to be able to see clearly through the screen. If you find that there is a build up of coffee oil, you can do one of two things. First you can use a scribe to clean the screen and then soak it in some machine cleaner or you can simply replace it with a new screen.

While the screen is down it is a great time to scrub the diffusion disc. If you look up into the group you will see what appears to be a large slotted screw, this is the diffuser.The disc is made of brass thus you should use a brass brush to clean it. A simple solution of machine cleaner applied to the brush will aid with the removal of coffee oils. Make sure that you have removed all traces of coffee oil and debris from the surfaces that are now exposed, and prepare for the reinstallation of parts.

Now its time to reassemble the screen and gasket assembly. The group screen as mentioned earlier is held in place with the group gasket. Take the new gasket and insure that the beveled edge is facing up. Squeeze the group gasket around the screen. Now take the assembly of the two items and place them on your filter handle without the filter basket in place and insert the entire assembly into the group head. Give the handle a turn as though you are locking it in place to brew coffee, this will insert the gasket into the groove that holds it in place. To complete the installation insert the filter basket back into the filter handle and insert it into the group head, this will completely force the gasket into the proper position. While most E61 groups use an 8.5mm gasket there are some that use 8mm and 9mm. make sure that you use the proper thickness gasket for replacement. Your portafilter handle should be in the 6 o’clock position when installed. If this is not the case you need to use a different thickness gasket or paper shims to create the correct spacing.

Here we have the assembled screen and gasket. Note the beveled edge of the gasket is facing up, this will ease installation.

To install the assebly, remove the filter basket from your portafilter. Now take the assebled unit and place ontop of the portafilter and install into the machine. Give the portafilter a good twist to the right to set the gasket in place.

This photo shows the use of a paper shim to get the correct spacing of the group gasket.

There, now you have completed the job of group gasket and screen replacement. Simple maintenance like this will ensure that your espresso machine operates the way it was intended to and your espresso will be just how you like. Next article we will do a photo essay of sorts showing all of the components of the E61. Till next time…