Espresso and espresso brewing is an ongoing evolution. New trends and technological advances occur at a rapid pace in today’s coffee world. New coffee markets emerge as more mature markets continue to expand. Consumption increases as customers become more sophisticated in their coffee preferences.

Greater understating of coffee and espresso technology is not solely a result of locked away R&D people wearing lab coats in the foothills of Italy. Sometimes advances come from the ‘field’ as they say. Take the Naked or bottomless portafilter: it has revolutionized espresso brewing and sparked an unbridled enthusiasm for tactile appreciation of brewing. And the drinks do taste better. It is geeky and a little tecky but shows the error of improper dose and tamp within seconds of activating the brew switch and pulls a sexy shot when done right. 

First off, what is the naked portafilter, sometimes called the bottomless portafilter? It is a traditional spouted portafilter for the espresso machine that has been altered by removing the bottom of the portafilter including the spouts. The filter basket is then seated on the upper portafilter rim; with the lower portion of the portafilter and spouts completely removed, the espresso as it is brewing only has the fine holes of the filter insert to deal with. Nowadays most espresso machine manufacturers offer the altered portafilters for extra cost. But most of us have an extra portafilter not in use and can take it to a machine shop and have the mechanic saw off the bottom. A metal file will soften the edges and away you brew. 

So how did all this come to be? Chris Davidson, a formidable baristi in his own right, now Coffee Trader for Atlas Coffee Importers in Seattle Washington USA, is credited with coining the term “bottomless portafilter” along with barista friend Jacob as a collaborative effort in 2005. Both were slinging shots of espresso at a well-known Seattle espresso bar at the time. Chris had been a barista champion finalist, barista trainer and coffee roaster for a few years. “Jacob Ellul-Blake and I co-invented it, I’d say,” according to Davidson. “I came up with the idea, and he chopped the first portafilter in his garage at home. Jacob was at Zoka at the time, and worked for La Marzocco for years after as a product designer. He’s now designing motorcycle parts.”

 So what was the logic behind the invention?

“The inspiration was purely for training purposes,” Davidson said. “Jacob and I didn’t think about the effect it would have on the cup. I don’t consider myself an inventor type, particularly. I do come up with the occasional creative idea, but Jacob for sure is someone who gets hands-on with the execution of ideas.”

Another barista posted about the bottomless experiments online and the rest is history as they say. 

As a trainer, I personally find it an invaluable tool for baristi to use to evaluate the quality of the espresso long before the 25 second pull time is up. Improper grind, dose and/or tamp are visible to the naked eye immediately, with pinhole squirts of water streaming at off-angles showing extraction malfunction.

When dosing fresh ground coffee into a portafilter basket, the coffee grounds must be exactly level and settled prior to tamping. Tamping is the act of firmly packing the lose coffee grounds (powder) into the filter basket. 

Many baristi understand the pack must be no less than 18kg pressure, and perfectly, repeat, perfectly level. If there is any angle to the firmly packed coffee, the high temperature, high pressure water will find its way through the easier path when brewing, thereby under-extracting and even over-extracting the very same espresso. 

With the naked portafilter, only the resistance of finely ground espresso, the 8 to 10 bars of pressure, and the skill of the barista who grinds and doses the coffee affect the brew (all other elements being equal). Using a naked portafilter, within seconds of activating the brew switch, the barista will know if it is a good shot of not. Tiny spurts of water find weak spots in the grounds and create pinholes where water gushes or “channels” through. Imagine the perfect swirling motion of honeyed streams of espresso as it all comes together on one spiraling ribbon of perfection into a preheated demitasse cup. Sounds great, yes?

During the Cup of Excellence this May in Guatemala City, cuppings were held at the formidable headquarters of Anacafe which hosts prestigious coffee laboratories, offices and the Anacafe coffee and espresso school. The school features the latest and greatest in all things espresso and includes the bottomless portafilter. 

Anacafe coffee trainer Enrique Molina spoke about the bottomless portafilter which he uses in advanced barista classes. 

“I use the bottomless portafilter to improve techniques of the professional barista,” Molina confided. “Through its use, a barista will understand the purpose of dosing and tamping and how finite adjustments positively impact the espresso.” 

Molina insists he can taste the difference between espresso brewed in a traditional portafilter versus the bottomless. 

“The espresso is sweeter with less contact between it and the metal,” he claimed.

Tea&Coffee Asia tends to agree, the espresso will also retain heat longer as there is no metal to rob the espresso of heat. 

So, if there is a tool that helps baristi understand the perfect shot and how to get there, we are all for it. There are many things that come and go in coffee world. The bottomless portafilter will stand up to the test of time. 

Drink Up!