More on how the buzzworthy home espresso grinder is changing the game.

BY DAVID SCHOMER
SPECIAL TO BARISTA MAGAZINE ONLINE

Photos courtesy of David Schomer

Yesterday, we released part one of this article. Today, David Schomer continues his thoughts on La Marzocco’s home espresso grinder, the Pico, and how it’s revolutionizing the coffee industry.

After Synesso introduced PID in 2005, I focused entirely on grinding as the next frontier of improvement, and it became clear that two principal challenges emerged. 

1. Particle Control

One challenge the old dosers presented was the ability to maintain the exact distribution of fine particles within the powder on the way to the portafilter. We learned that any static en route would ruin the shot by pulling the fines out of place, so any free-floating powder left in the machine meant failure on this front, as well. Static mitigation does not work; the only way to preserve the integrity of the mix of particles is to impact them just enough enroute to trap the fines. The dosing system on La Marzocco’s Pico grinder does this perfectly by shooting the powder into the portafilter with spinning ramps, creating a “jet” of ground coffee.

2. Chambered Coffee

No grinder had yet solved the problem of leftover grounds being trapped in the grinding head between shots. Roasted coffee still contains a little moisture, and chambered ground coffee instantly begins to absorb or expel moisture within the trapped powder. Ground coffee is wildly hygroscopic, i.e., it freely exchanges moisture with the ambient atmosphere. 

Moisture content within the ground coffee affects the rate of flow of espresso from the grouphead. More moisture in the powder slows down the extraction; less moisture speeds up the pour.

It is hard to overstate the importance of controlling the rate of flow of espresso into the cup. This is intimately related to the final volume of the shot, of course. At my Seattle coffee company, Vivace, we favor a slow short shot, maybe 22ml extracted in about 35 seconds. This rate of flow and ristretto volume maximizes caramelized sugars and origin flavors into the cup. Shot times that are too fast—say, less than 27 seconds to hit our ideal volume—will be sour/astringent and have less caffeine. Too slow of an extraction—over 40 seconds, for example—may be hollow, sour, or bitter.

The effect of flow rate is much more nuanced than simply saying good shots exist between 27 and 40 seconds. What is fascinating to me is the range of flavors that exist within the boundaries of a decent shot. There is a spectrum of flavor nuances from more fruity (faster pours) to heavier umami and body (slower pours).

Take an Ethiopian Sidamo natural, for example. As it is with most Ethiopian naturals, the shot will have a heavy body and thundering chocolate umami balanced with notes of berry in the finish. Faster flows for this coffee—around 30 seconds total grind time—may highlight malic acid in the final shot and offer more fruity flavors like stone fruit or berry. Slower flows—in the upper 30s—emphasize heavier body and more savory richness, and berry flavors may recede a bit.

A master barista is able to decide what flavors they want to emphasize for any given coffee they are serving. If Dr. Joseph John of Josuma Coffee, who is a very sophisticated lover of our espresso, comes into our shop and asks the master barista to up the berry flavor a bit in his Sidamo, they can easily fulfill the request by aiming for a 30-second pour.

Precise control of the flow rate reveals the impossible beauty of the espresso method of coffee brewing. Within each well-roasted coffee is a host of flavors that a highly skilled barista can reshuffle at will by controlling the flow rate. And of course, this can only be achieved if there is no ground coffee trapped in the grinder.

Note: If you can follow this article, you understand that all factors in creating an espresso—temperature, coffee freshness, a clean, well-maintained machine, and the barista’s technique—must be perfected to taste the nuances in flavors at each flow rate.

So, for 37 years, we have been guessing how much to purge the grinder to expel ground coffee that has been affected by moisture exchange, and ultimately throwing out lots of shots when we misjudge. (My DRM unit had 12g of chambered coffee trapped in the head and dosing chamber; the Niche Zero got it down to four grams). My baristas are exacting professionals, and guessing the condition of the trapped coffee has always been driving them nuts.

With the Pico you adjust the grind as needed, and all of the coffee at the new setting is what you were aiming for, absolutely no powder remaining in the grinder at the previous grind setting.

With the Pico, waste and guesswork are over. And the precise control of grind reveals a whole new dimension in profiling the coffee of your choice.

Dosage Control

Of course, the dosage of coffee impacts the flow rate of the espresso quite directly. I like to tell baristas in training that dosage control by feeling it with your finger is very difficult.  

Weighing the powder as it grinds to an accuracy of 0.1g solves this dosage problem perfectly. I will try to couple the Pico with the Bluetooth scale made by Acaia, so keep an eye on Vivace’s Instagram.

Currently, the Pico does not contain a scale to weigh the powder and turn the grinder off at the desired gram setting.

Heat Control

The ground coffee ideally should be slightly warm exiting the grinder, about 95°F. But grinding by the cup, turning the hefty motor on and off constantly, creates a lot of heat. In this area, the stock Pico overheats very quickly, making it suitable only for home use. After about 12 sequential shots, the powder is about 110°F, and the shots thin out immediately.  

The base of the hopper is well-designed to be removable without spilling beans; it automatically shuts when turned and lifted. A simple 3D printed collar mounts easily to accommodate our Mazzer bean hopper.

So far, my vented grinder is handling a medium commercial volume with a 55cfm fan and effective vent placement. Let’s see if it can keep cool at Brix on a Saturday—fingers crossed.

The Vivace baristas love the grinder. They hadn’t realized how difficult it had been to control flow rate before using the Pico. Now, they have a consistent grind right at the burr set with no purging. Each bean is absolutely fresh until it hits the portafilter. We have had virtually no compromised shots. And the grinder is quiet: It sounds like a gentle wind in the trees.

This grinder is the biggest improvement in the art of espresso since PID espresso machines. Having this grinder on my bar is a dream come true. In espresso and many other pursuits, perfect is the enemy of good. Humility is always required in the seduction of the bean, but may I say we are much closer than ever to each shot tasting like freshly ground coffee smells.

ABOUT THE AUTHOR

David Schomer started Espresso Vivace on April 18, 1988, in Seattle, Washington. From day one, the company’s charter has been to “research, develop and promote caffe espresso as a new culinary art.” David’s published works include over 100 articles for coffee trade magazines, and his series of books, which launched in 1996. The series is also available in Japanese, Korean, and Chinese. David’s video course Caffe Latte Art from 1995 is known to have inspired the explosion of latte art everywhere. David is most widely known as the father of latte art. David is currently focused on roasting and preparing his beloved espresso at Espresso Vivace’s two locations in Seattle.

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