The Portafilter Won’t Lock Or Is Unscrewing Itself (Solved!)

Are you tired of wrestling with your espresso machine’s portafilter every time you crave a fresh brew?

This article provides easy and practical solutions to fix a portafilter that won’t lock or is unscrewing itself, helping you reclaim your perfect cup of espresso.

How To Fix A Portafilter That Won’t Lock?

To fix a portafilter that won’t lock, make sure the basket is fully inserted, use less coffee if overfilling, apply force with new machines, warm up the machine before use, check and replace any damaged parts, and ensure the portafilter is clean.

If the portafilter unlocks during brewing, you may need to replace worn-out parts, reduce the amount of coffee used, or clean and dry the seal properly after backflushing.

Let’s dive deeper into the solutions below.

Portafilter Won't Lock Or Is Unscrewing Itself

Insert The Basket Fully

Make sure that the basket is fully inserted into the portafilter. It should be in and not partially pushed down. Press it down on a flat surface if necessary, applying a bit of force if needed.

Generally, the coffee filter basket protrudes slightly (around 1 millimeter) from the portafilter handle that holds it. However, this can vary based on the manufacturer.

You can tell that the basket is seated properly when it feels like it’s stuck and you can’t remove it easily with just your fingers.

So, if you’re using a coffee machine from one brand and a filter basket from a different brand, the fit may not be the same as with the original basket.

Don’t Use Too Much Coffee Grounds

When dealing with a portafilter that won’t lock, the excessive use of coffee grounds is often a key issue. Using too much ground coffee can make it very hard to lock the portafilter in.

To fix this, aim for about 18-20 grams of coffee for a double espresso shot. Using a coffee scale can help ensure accuracy. Make sure you’re using the right basket, so in this case, a double shot basket.

When you’re using too much ground coffee you also run the risk of causing a portafilter sneeze after brewing if you do manage to get it locked in.

Once, I tried to lock in my portafilter, not realizing that the puck from a previously brewed espresso was still stuck on the group head screen of my machine. It took me a moment to notice that this was preventing the portafilter from locking in. So, before you start troubleshooting other areas, make sure this isn’t the problem.

the right amount of coffee grounds
The right amount of coffee grounds

Apply Extra Force

It’s normal for new machines to require a bit more force to lock in the portafilter, the new gaskets can be a bit rigid in the beginning.

Firmly grip the handle and turn it into place. Be sure to place your machine on a non-slip surface to prevent it from moving.

Warm Up The Espresso Machine

Before attaching the coffee-filled portafilter, run a few “dummy” shots without the portafilter. This will warm up the shower head, making it easier for the portafilter to lock in.

Check The Shower Screen In The Grouphead

The issue could stem from a damaged shower, also known as the dispersion disc. The shower, a plastic component located above the metal shower screen, is responsible for evenly distributing water across the coffee.

A broken shower can cause a slight bulge in the shower screen, which can then obstruct the portafilter from locking into place.

To check whether this is the root of the problem, follow these steps:

  1. Disassemble the group head: Start by unscrewing the center screw and removing the shower screen. Above the screen, you’ll find the dispersion disc. Remove this as well.
  2. Inspect the dispersion disc: Check the plastic dispersion disc for any signs of damage or breakage.
  3. Replace if necessary: If the dispersion disc is broken, a replacement will be needed. You can obtain replacement parts directly from Breville’s official website or trusted third-party retailers.

In addition, it’s worth noting that a similar problem could arise if the gasket (the rubber seal where the portafilter locks into the group head) is damaged. A damaged gasket may impede the portafilter from securing properly. In such a case, the gasket would also need to be replaced.

Ensure The Portafilter Is Clean

Check the bottom of the portafilter to make sure there’s no rubber mat or any residue that might prevent the basket from fully settling in.

For instance, there could still be remnants from the last coffee brew attached to the shower screen, as I previously mentioned.

Give It Some Time

It’s common for new machines to have a tight fit at first. With regular use, the components will naturally adjust to each other, and locking the portafilter will become easier.

Please remember that while a certain level of force is needed, you should never feel like you’re straining or might break the machine. If problems persist, it’s best to reach out to the manufacturer for assistance to avoid causing any damage to your machine.

How To Fix A Portafilter That Is Unscrewing Itself?

After you’ve finally got the portafilter locked in, there could be a second problem where the portafilter unlocks itself during brewing because of the pressure build-up. The most common reason why this happens is that the portafilter is not all the way locked in. Some other reasons are:

Group Head Gaskets Are Worn Out

If the portafilter unscrews during pouring, one potential reason could be that the group head gaskets or the lugs on the portafilter are worn out. Over time, with extensive usage, the lugs or gaskets can wear down, causing the portafilter to lose its tight grip.

If worn lugs or gaskets seem to be the issue, you could carefully file them to reduce their slope. You will need a fine file for this. Be careful not to remove too much material.

If this doesn’t resolve the issue, you may need to replace the gasket. Consider borrowing a portafilter in good condition to determine if the issue lies with your current portafilter.

Always remember to keep your portafilter in the group head when not in use. This practice will help to extend the lifespan of the grouphead gasket.

Overdosing The Portafilter Basket

Overdosing the coffee basket can cause the portafilter to unscrew during the pour. If there’s too much coffee, it can prevent the portafilter from locking securely into place.

You can try a test. This involves filling the coffee basket with your usual dose of coffee, gently pressing a cent coin on top, then locking the portafilter into the group head and removing it. If the coin leaves a clear impression on the coffee, indicates you might be using too much coffee.

To resolve this, try reducing the amount of coffee you use for each shot (under-dose), and check if the issue persists. This could also prevent you from locking the portafilter in the first place, as discussed earlier.

The Seal Is Too Wet Or Soapy

If the seal is excessively wet or soapy, perhaps from backflushing, it can cause the portafilter to slip or unscrew during pouring. This can create a less-than-ideal seal between the portafilter and the group head.

Ensure that you thoroughly clean and rinse the seal after backflushing to remove any residual soapiness or wetness. Also, consider giving it enough time to dry.

If cleaning doesn’t seem to resolve the issue, inspect the seal for any wear and tear. You may need to replace it if it’s no longer able to form a tight seal with the portafilter.


In summary, overcoming portafilter problems can be as simple as proper insertion, optimal coffee quantity, adequate force, warming up the machine, regular maintenance, and cleanliness.

With these straightforward solutions, you can ensure that your espresso brewing process is smooth, delivering that perfect cup every time.

Thanks for reading!