The E61 Brew Group. Demystifying the Mystique.
(I’ve noticed that a lot of people use the terms brew group and group head interchangeably. But they are not one and the same. The group head is part of the brew group. The brew group is the whole assembly that circulates the water around and through the front of the machine, down through the grinds in the portafilter. It is made up of the group head. The manual lever, which activates the pump for the brewing process and the pressure release system. And the pressure relief valve. What makes it uniquely an E61 group head, is that the lever and valve are manual. The moment you put an electrical unit in, like a solenoid valve, it ceases to be an E61 brew group.
Now you can have a machine with just the E61 group head. The group head is the channeled, metal disc-shaped piece of brass that the portafilter locks into. Again, it is just one piece of the entire brew group assembly.
Okay, enough of brew group semantics 101. Onto the article, which focuses on the whole enchilada - the brew group…)
The E61 Brew Group. It’s been hailed as the industry standard, revered in coffee circles worldwide, and reverently passed over the lips of every espresso connoisseur in search of the perfect espresso machine - from the newbie to the well-seasoned barista.
o what I want to know is, why all the hooplah?
And with that, I set off to spend some time with Todd, a tech at Whole Latte Love, who knows espresso machines inside and out, and talked to me with a knowledge and passion like I talk to my friends about poker.
The result of good brewing
Now I know a fantastic espresso when I have one. But when Todd extracted an espresso for me from a prototype machine that used the E61 Brew Group, it took my appreciation of espresso to a whole new level. It was phenomenal - from the foamy, light brown crema on top, to the aromatic fragrance that filled the air in just 22 seconds, to the amazingly smooth yet bold, rich taste as I sipped it from the preheated shot glass.
He looked at me expectantly. "Well?"
"Wow," I responded, to which he nodded knowingly. "Why?"
"Heat. Consistent, stable heat. And that’s the beauty of the E61. And why so many prosumer (professional quality consumer machines) and commercial machines use this brew group over all the others.
"You see, the boiler has a temperature of 200 plus degrees. If that temperature varies in the slightest from the boiler to the moment of extraction, you’ll end up with sour espresso. The E61 is engineered to maintain that temperature consistently right through extraction. Absolutely no fluctuation. In other words - it’s perfect."
And, after watching me savor the rest of my espresso, he took me to back to his workshop for an up close and personal encounter with the workings of the E61.
You could kill someone with this thing
"Here, pick it up," Todd said, handing me an E61. I was surprised at how heavy it was. It reminded me of a dumbbell, except prettier. Eight and a half pounds of chrome-plated brass. I think the brew group itself weighed more than my entire espresso machine a friend gave me for Christmas a few years back. (Mental note: re-evaluate that friendship.)
"It’s the density that helps it maintain the water temperature," Todd explained, and I vaguely recalled a lesson from high school physics about mass and heat. "But its simplicity of design and lack of any electrical element is what makes it so reliable. As long as you take care of it, the E61 will last you for years and years. It doesn’t break down, and never fluctuates in its performance - delivering a perfect espresso extraction after extraction." But more on caring for the E61 later.
Back to the roots
The E61 brew group is a manual or piston driven brew group. It was first introduced onto the Italian marketplace in 1961 in Faema’s - the renowned Italian espresso machine manufacturer - revolutionary E61 espresso machine. The E61 was the first espresso machine to use an electro-mechanical pump - making it a semi-automatic machine in today’s lingo - replacing the manual or hydraulic pistons that up to that time had characterized the machines’ functioning, and has become the industry standard because of its amazing ability to keep the at a consistent temperature of 200 degrees - the ideal temperature for extracting espresso. In fact, almost every commercial espresso machine and high-end prosumer machine today feature the innovations first seen on the Faema E61 - the rotary pump and the heat exchanger system, which produce the flash-heated, fresh brew water and on-demand steam. But only the best have purchased the innovative E61 grouphead design and technology to include on their machines - such as well known and trusted brands like Expobar and ECM, just to name a few.
While it can be modified, the E61 brew group in its purest original form has only has one electrical part - the micro-switch. This simplicity of design is what makes it so reliable. Looking at it, you see the group head front and center, the manual 3-way lever to the right, the pressure release valve below. The whole thing is made of channeled chrome-plate brass. Inside, there is a minimal series of springs and moving parts.
The circular group head has channels cut through it to keep the water circulating and the brass warm. And it literally screws onto the machine. If you unscrew the large bolt at the top, and remove the spring - which provides resistance to the valve - you’ll see a small hole not much bigger than a pinhead. This tiny hole is where the water shoots through the system under the built-up pressure produced by the heat - the description of the thermal-siphon system.
Leveraging Your Brewing Process
The brew group’s functions are all activated with a manual lever that has 3 positions. Up turns the pump on. The middle position turns the pump off. And the down position depressurizes the system. It’s that simple.
With the lever up, it raises a piston in the brew group that lets the water pump through the brew group from the boiler at 120 psi using forced heat pressure. The water then circulates around the group head and seeps through the finely ground coffee you’ve tamped into the portafilter which snugly and securely attaches to group head in the grooves that have been cut into the brass. It is leak-proof thanks to the gaskets that form the seal when the portafilter is correctly in place. This initial part of the brewing process is called pre-infusion, which basically primes the grinds for the water to come through them evenly in order to get the most flavor and aroma out of them.
When the coffee begins to drip into your glassware, the lever is then pressed down, which pushes the piston down, causing the rest of the water to plunge through the coffee grounds. At the bottom of the portafilter is the shot basket, which has 180 tiny holes to keep the grounds out of your cup. And above the portafilter, the E61 has a shower screen to keep the grinds out of the system and the machine. These two screens offer dual protection to your machine and your espresso.
When the lever is pushed all of the way down, the brew cycle or extraction of espresso is complete, and you have pulled - extracted - a spectacular shot of espresso as evidenced by the fine crema - or light brown froth - on the top of your shot. It also sucks the coffee moisture from the system and portafilter, making the puck (used coffee grinds) easy to remove and keeping the portafilter cleaner.
Okay, so now that we know how it works, how do you take care of your E61 Brew Group? Todd was kind enough to give me a lesson in this as well.
Backflushing your home system removes the oils and "schmutz" - as Todd puts it - from the grouphead and parts from the boiler forward. You should backflush your home system every 2 to 3 weeks, depending on usage. And use detergent - Todd recommends Urnex Espresso Machine Cleaner for excellent results.
First remove the shot basket from the portafilter and put in the backflush disk - or blind filter basket. (You’ll recognize this filter basket immediately, as it has no holes in it.) Then put the portafilter back on the machine. Hit the brew lever for 5 to 10 seconds. Listen for the system to pressurize. You’ll know it’s pressurized because the noise will decrease. At this point, push the lever down. A moment later, a pressurized stream of water will shoot into the drip tray. Check the drip tray. If this water is dirty, simply repeat the process until the water runs clean.
If you’re using detergent, put 1/2 teaspoon of detergent in the backflush disk, and run through the steps above. Just keep backflushing the system until the water runs clean so you won’t have any detergent in your espresso - yuck. It takes about 10 times.
To clean your portafilter, shot basket and drip tray, simply mix a spoonful of detergent with hot water and let them soak, being careful not to get the cleaning solution on your plastic portafilter handle (can you say piranha?). There’s no scrubbing necessary. The detergent will literally lift the crud right off the components. Just rinse clean, put the shot basket back in the portafilter, wipe out your tray and you’re ready to make espresso all over again.
A quick word about scale. On the spring and around the pinhead at the top of the grouphead, you may notice white crust - like plaque on teeth. This is scale buildup that occurs over time. It’s a combination of coffee oils and water minerals. Talk to a technician like Todd directly before you try to clean it. And don’t fret, it takes years for this buildup to occur, so it’s nothing to worry about.
"And that’s the E61 brew group," Todd concluded. With that he showed me out of the shop. I left armed with knowledge, a greater appreciation of the process, and bitter disappointment that he didn’t offer me a second espresso, as the buzz from the first one was wearing off even though its incredible taste was still fresh in my memory.
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