In this age of change, technology seems to advance at a rate that cannot be measured. Robotic assembly technology has placed sophisticated electronic devices are in all areas of our lives. Wristwatches with GPS, sunglasses with digital music players built in, and ballpoint pens with video cameras in them. Amazing, mind boggling, and in some cases, questionable. These advances have nearly eliminated the electronic repair shops that use to dot every town and city. Drug stores use to have rows of tube testers for the do-it-yourself crowd. Folks would show up with a pile of vacuum tubes, individually wrapped in a paper towel, each numbered with a piece of masking tape. Spin the wheel to advance the roll to the proper number, plug the tube into the indicated socket, set the dials, and press the "TEST" button and watch the analog needle. Now what isn't disposable has to be sent in to get fixed. Everything has to go back to the shop or off to the electronic recycling center.
      Even in the world of espresso, electronics have appeared. For the home user we see the PID now factory installed and preset for many machines, a few of them even under the $1000 mark. Programmable dosing, and even digital electronics on grinders that can be set for a period of time, and a couple that grind by actual weight of grounds!
      Juxtaposed to that is a noteworthy invention that is 50 years old today. The event is marked by the original U.S. filing of patent #3,230,974 on September 25, 1961 by Ernesto Valente. The invention was named after the way it worked: "Alternately Seating Valves." We refer to it as the E-61 group. You can download a copy of the original patent in PDF form HERE.
      In around 1960, Faema was working on inventing the next generation of espresso machines for commercial use. Up to this point nearly all commercial espresso machines were lever machines. The operator either had to pull down on a lever using the barista's own muscle to move a piston forcing water through the coffee, or with the same action, compress a spring and release the lever to allow the springs force to push the water. Faema's change was to use a pump to pressurize the water, but they wanted to emulate, if not duplicate the quality of coffee that lever machines created.
      The solution invented by Ernesto Valente, the E-61 group, used a valve which opened at about 1.5BAR. That valve allowed the water, at that low, initial force, to flow into a sub-chamber. Until that chamber was filled the pressure in the entire group including the water hitting to coffee, was held at around 1.5BAR. That infusion valve and infusion chamber was an important part of the patent that helped the E-61 create "creamy coffee... allowing a desired interval of infusion between the opening of the cock and the distributing of the drink."
      We have seen a lot of changes over the last fifty years in the world of espresso, but the E-61 group remains essentially unchanged. The three-valve system is still the same, operated by the sale centrally-located cam. The infusion chamber still slows the initial delivery of water to the coffee, and the group is still saturated by hot water, keeping it at or near the desired brew temperature for more consistent results. Even the spring that regulates the opening point of the infusion valve is still 1.5BAR. One notable difference is in the area of the gicleur (jet) which regulates the flow of water into the brewing area. Originally, Ernesto specified that a needle could be forces into the gicleur's opening to clear it of any foreign matter. Today, the gicleur is protected from clogging by a small, tubular screen in the upper chamber.
      Today, September 25, 2011, fifty years later, the E-61 group is sill found on many new machines, and I do not think it inaccurate to say that it is the single most-used, and single most-recognized group in the industry. And why not? Its shiny chrome surface and undulating shape are beautiful and in the right hands and fed quality coffee it makes great espresso. It is also very simple to disassemble and overhaul or clean. It's simplicity and exposed nature means that two or three common hand tools can have the entire group apart in just a couple of minutes.
      I invite you to use the above link in my article to download the patent. it contains the original text of the patent, and for those who enjoy such things, it makes a delightful and educational read. I find Ernesto's insight in inventing this group amazing. Fifty years later, the espresso it can create is a testament to his creativity and engineering skill.
      So Happy Birthday E-61, and thank you, Ernesto Valente for fifty years of wonderful espresso!