How to Do a Flow Rate Check on Your Machine

Make this test a semi-normal part of your cleaning and maintenance routine

What is a Flow Rate Check?

A flow rate check is a test designed to assess whether or not the flow restrictor (gigleur) in the machine’s brew boiler assembly has become occluded with scale or other debris.

Should I conduct a Flow Rate Test?

Every owner of a La Marzocco should conduct a flow rate test semi-monthly as part of their normal maintenance and cleaning routine.

How do I do a Flow Rate Test on my La Marzocco?

To conduct a flow rate test, all you need is a bowl capable of holding up to 800 grams of water, a digital scale set to weigh in grams, a timer, and a La Marzocco espresso machine.

1. Remove the portafilter from the group
2. Make sure that your reservoir is full
3. Place the bowl on the scale underneath the open group
4. Tare (zero) the scale
5. Open the group and allow water to flow for 30 seconds.

We’re looking for the amount of water that comes out in that 30 seconds.

What do my results mean?

For a GS3, with a .6mm restrictor, we are looking for approximately 250 grams of water in 30 seconds.

For a Linea Mini, with a .8mm restrictor, we are looking for approximately 500 grams of water in 30 seconds.

If you find that your flow rate is significantly lower than specification, this simply means that your flow restrictor is occluded and needs to be replaced. It does not mean that your machine has been damaged, or that it needs to be de-scaled.

The solution is to have the restrictor replaced, and then take a hard look at the water that you’re using, and also how you’re using your machine in terms of how long you keep it turned on vs. how often you use the machine. If you need to know more about water, take a look at our “Water for Home Espresso” post.


If you have questions, please don’t hesitate to call our Technical Experts at 206.258.2532 option 3. You can also email them at