How to Make a Naked Portafilter for Your Espresso Machine
Typical Two-Spout Portafilter
What Is a Portafilter?
The naked portafilter is a fairly new innovation in the old process of making espresso. Typically, a portafilter, which holds the coffee grounds and gets clamped to the espresso machine, has one or two spouts that direct the coffee into the espresso cup. By removing these spouts and making it "naked," the coffee maker can clearly see how effective their coffee extraction process is, enabling direct feedback and greater quality control.
Finished: The Naked Portafilter
Why the Naked Portafilter Is So Great
The naked, bottomless, or crotchless portafilter is a great innovation that provides the home enthusiast or barista with a fantastic training tool. There are many variables to control when making a shot of espresso. Improper grinding, measuring, or tamping of the coffee can result in a wide variety of bad espresso brewing. The naked portafilter offers a clear window into the coffee extraction process allowing common errors to be seen quickly and easily.
Machining a Naked Portafilter
Below are the steps I used to make my own naked portafilter. I made use of a metal lathe and some basic lathe cutting tools. The pictures below are of two La Pavona portafilters: one chrome, one brass. Please understand that there are a million ways to approach this simple machining project. This is the way I have approached it with the tools I have.
1. Unscrewing double spout
2. Removing the portafilter handle
3. Clamp portafilter in lathe chuck
4. Cutting off spout threads
5. Spout threads removed
6. Time to open up the hole
7. Boring open the hole
8. Nearly finished boring the hole
9. Adding a chamfer to the hole edge
10. Machining is complete!
Naked portafilter in my espresso machine
Pulling a shot with the naked portafilter
Perfecting the Naked Extraction by Dan Kehn
- Great article on using a naked portafilter
Normal problems that occur during espresso making are: blonding, channeling, over-extraction, under-extraction, and pre-infusion. Get the definitions of these terms and a lot more here. Click on the link to read.