E61 Group Head Maintenance

In the sixty years since Ernesto Valente had the idea for this groundbreaking design, the E61 group head has become ubiquitous on espresso machines the world over. You can find this massive chunk of chrome-plated brass affixed to machines spanning all sorts of manufacturers and styles.

Its distinctive exposed look, like that of the lever machines that preceded it, allows it to shed heat to the atmosphere to slightly cool the (very) hot incoming water down towards a more reasonable brew temperature. The thermosyphon effect also helps to stabilize the temperature of the group by constantly circulating water from the boiler/heat exchanger through the group head.

It’s because of these features, and its robust design, that it has become so much of a staple. As tough as it is, it still has a number of moving parts that can wear down over time. Below, I will describe the parts to be aware of, and when to know to replace them.

Cam Lever

When you lift and lower the brew lever, you are turning the cam attached to the end of that shaft to actuate the brew, preinfusion, and drain valves to allow water to go to the coffee and the drain respectively.

To prevent that same water from leaking past the cam lever, there are two donut-shaped gaskets compressed around its shaft. These gaskets, and the DOW 111 lubricant that keeps the cam lever moving smoothly, can over time wear down. This can lead to a brew valve that squeaks when it’s turned, leaks water, or refuses to stay in the brew position.

When this happens, we recommend using our E61 Cam Lever Gasket Repair Kit to replace those gaskets and relubricate everything so it runs smoothly again.

Group Gasket

Each time you lock the portafilter into your E61 brew group, it compresses your group gasket so that it seals and blocks water from leaking around the portafilter instead of through the coffee. While they may last for a number of years, we recommend replacing the group gasket once a year.

If you wait too long, then they become difficult to remove. What would normally be an easy two-minute job could turn into an hour-long process of chipping away at desiccated rubber with a chisel or awl. If it begins to leak around the portafilter before the year is up, then you should go ahead and replace it anyway.

Most machines come installed with an 8.5mm gasket so you can use this 8.5mm group gasket as a direct replacement. If you’re using a bottomless portafilter, however, then I would recommend that you use the slightly thinner gasket like the 8.0mm group gasket.

Brew / Pre-Infusion / Drain Valves / Mushroom Group O-Ring

Inside of your group, the heavy lifting is being done by three valves. In order from the top of the group to the bottom, you have the brew valve, the preinfusion valve, and the drain valve. The brew valve is what opens to allow water to make its way to the shower screen.

The preinfusion valve allows for a gentle increase to full pressure, rather than a sudden increase in pressure all at once. The drain valve is what releases pressure once the brewing is complete so that your portafilter is easier to remove and doesn’t spray you with water when it’s removed.

Many of the symptoms that tell us that valves need to be replaced can also be caused by insufficient backflushing or cleaning where a build-up of coffee residues can ensue. It’s always a good idea to backflush and clean your group before deciding to replace your valves. Learn more about that process, in our "Backflushing 101" guide.

Signs that you may need to replace the valves in your group include:

  • The portafilter is difficult to remove and makes a “hissing” noise when it is
  • Water constantly drips from the shower screen, even when the brew lever is down
  • Water constantly drips from the exhaust of the group, even when the lever is lifted

Whenever replacing one of the group valves, it is a good idea to replace all of them, as well as the o-ring for the group mushroom since they all tend to go bad at around the same time.

Other Components to Consider

In addition to the above parts, there are also a few other components inside the group that you may rarely find yourself needing to replace. In general, unless something catastrophic happens, these don’t need to be changed. Your Teflon seals will last the lifetime of the machine unless they are excessively twisted or punctured while disassembling the group. The springs behind each of the valves and compressing the cam lever gaskets likewise tend to last as long as the machine.

Differences

Though E61 groups may all look the same, there are a number of machines and kits that modify the internals of the group. For instance, both the Vesuvius and the Flow Control kit that we sell on our website replace the spring that controls the Pre Infusion valve. This is to prevent it from opening while brewing, so as to give you more control over the pressure and flow of water going towards the shower screen.

If you believe you have one of these machines, feel free to reach out to our Service Department so that we can find the correct replacement part for you. They can be reached on our contact us page or (518) 452-5995.