The relatively short and, in many ways obscure, history of espresso coffee has produced a phrase that sticks tight to the Gaggia Gilda...."The First Espresso Machine for Domestic Use". To modify, it would be better said that it was the first domestic machine for "Crema Cafe", as discovered by Achille Gaggia. I say, discovered, rather than invented as this process seems to have been there all along just waiting for someone to find the secret to unlock the beauty of cream coffee and open what has become the Modern Age of Espresso. To live that era of post war Italy is now impossible .....but having spent 6 months or so working on this machine to bring it back to full function I can sometimes feel the sparks of innovation, and commerce, emanate from this machine and almost intuitively recreate this historic time and place. That is the draw of these vintage machines....they can speak to us from the past and tell in some ways a story which has been lost or hidden....has become obscure and diluted through the retelling of just highlights. The Gilda reflects many things from that era....a man with a vision, a dream if you will, having happened upon a great discovery, and of course, turning this discovery to some commercial advantage in a very cutthroat environment of entrenched manufacturing, scarce resources, but with a populace hungry and eager for the good things in life.....wine, food, coffee.
So, this seems like a moment of challenge....and the machine reflects many challenges of engineering, design, public acceptance, marketing, not to mention manufacturing.....so let's take a tour through the machine and contemplate how these challenges were met by a simple entrepreneur with a big idea....its all in the machine, the 1948 Gaggia Gilda.
One of my favorite parts of the machine that tells so much about promotion is the badge. 100 years of espresso coffee machines. A stable, sound, reputable company. A company that you can put your trust in. In a sense this is the Centenarian model of the machine. Rock Solid! Dependable....been around forever. A name you can trust.
The materials.....ALUMINUM....smooth sleek modern aluminum....with a few touches of chrome plated brass. Again, from observation of the machines from this era, it seems that Italy was well populated by foundries, metal casting companies. Most of the parts of this machine are cast and polished with very few machined parts. Mold making, casting, polishing, but not a lot of metal turning but for a few cut threads . Let's take a look at the entire parts layout of the machine.....
Here you have it. The boiler is made in 3 parts: cast base with group containing the heating element, aluminum cylinder, and cast top cap. Very similar in design to a modern boiler made for economy sake from 3 parts, but these days from stainless steel. Cast base. Stamped drip dray and grate. Die cut under base cover. Brass piston and pressure valve workings. Many small parts to make the whole and many seals to fit them together.
The top cap must accommodate 4 functions: The center hole is for the assembly bolt that joins the 3 parts into one, the large threaded hole for the filling neck, the small threaded hole for the pressure regulator device, and the last hole to seal the piston rod in its travel through the boiler cap. Again, cast and tapped threads, using 1/8" BPP thread for the pressure valve fitting. A channel around the entire outside holds the seal....in our case an o ring, but originally likely lead wool or treated string or paper. The dispersion screen seems to be cut from a filter basket using a die or even possibly hand cut.
The boiler base, a much more complicated casting. One piece of aluminum which contains the extraction cylinder, a central tapped hole for the assembly rod to hold the boiler together, lower tapped sockets for the bolts that will join the kettle to the base, two holes for the installation of the heating element, and again, a groove around the outside for a seal. Note in this view how many engineering problems were addressed in one cast piece. The support device in the form of bolts for the legs. The cylinder has drilled holes in the sides to allow the water to enter the cylinder when the piston is raised above the holes. There is no water level tube on the machine, so as a safety feature, the heating element is placed below the holes for water entry into the cylinder. Yes, the machine can boil dry from careless use but the heating element will be submerged in water even when the level is too low to make coffee. Another safety device can be seen in the cup that surrounds the toggle switch.....making it difficult to accidentally turn the machine on by a casual pass of the hand.
A bottom view of the group shows that this is a very complex cast piece, but very much like most groups today. A machined groove at the lower inner cylinder wall retains the dispersion screen. Openings for the portafilter lugs and a ramp for tightening, a channel to retain the group gasket. All in continuity with the hot water in the kettle, and quick heat transfer through the aluminum. Add a high shine on the outside....whew, what a piece of work!
A small cover made of chrome plated stamped brass hides and protects the heating element terminals. This cover is held in place by the leg trim column which slides over the steel leg at the rear of the machine. No tapped holes are used to secure this cover.
My curiosity and enthusiasm led me to knock out the dispersion screen with a drift only to force me to discover how it was installed at manufacture. The secret was to form the screen into a curved bowl shape, insert into the bottom of the cylinder to align with the cast retaining groove and then flatten the screen into place with a hammer and dolly held inside the cylinder. I am positive that this is the only manner of installation. This view shows the screen with group gasket and heating element cover installed.
The boiler top and bottom speak to the engineering aspects of the machine and the kettle body brings us back to the brilliance of Achille Gaggia's promotional skills, and also the solving of another problem. The polished aluminum cylinder which forms the boiler would, of cours,e be subject to scratching and blemishes over time. To solve this, a double band of twined "Gaggia Gilda Milano" entirely wrap the body of the boiler, adding a strong visual design element, an unmistakable promotional identifier, and solving the problem of an occasional scratch or blemish on the high shine aluminum. No pun intended, but truly BRILLIANT!!
Now you can see the machine taking shape. The heating element has been electrified with the hot wire interrupted by a simple bipolar switch....ON/OFF. The wire routes along the right side of the base and is contained in the large diameter aluminum column in the back. the lower part of the boiler is in place along with a flat ring device on the left which stabilizes the bottom of the pressure valve drain tube. The machine now awaits the installation of the two basic functional systems.....the extraction piston and the pressure relief system.
The piston itself has a machined body made of brass connected to an extremely long rod. The piston body is made in parts....a bottom plate, a central body, a top plate, and a floating inner spacer that functions as a divider for the two u-cup piston seals. The entire assembly is joined by the rod. I was unable (or unwilling better said, for fear of damaging the piston) to remove the rod from the piston body. It is either swaged together or threaded, but this is the one part that I did not disassemble. The "floating" divider was most fortuitous for the successful resealing of the piston. Originally, like most espresso machine pistons, the u-cup seals have a rectangular format. In this case, the outer diameter is 1 1/2", to seal the cylinder at the same nominal diameter. The inner diameter of the seal is 1" (the OD of the piston body). Today, almost all standard u-cup seals have a square cross section profile so a 1" x 1 1/2" seal will be 1/4" wide and 1/4" tall. As shown above, this is the bottom or the power seal, which is responsible for sealing the piston on the downstroke. It is the all important seal for espresso extraction. The upper seal is responsible for sealing the kettle in the static position and for moving the water on the upstroke. In the case of the Gilda, there was not enough room for a second 1/4" seal, and the next available size down, 3/16" does not exist in a 1" x 1 1/2 size......remember the square profile and do the math. So the solution is to use the ideal seal on the bottom and a 3/16" upper seal (ID=1 1/8"). The piston body, for the upper seal, was shimmed out larger using high temperature silicone tape and successfully seals the entire piston in the cylinder both for the low pressure static seal and the high pressure power seal.
This approach to sealing a piston, by the way, is simply a matter of economics, for two perfect seals could be made for the cost of the mold (thousands of dollars). So for quite a few thousand dollars less than the cost of picture perfect LOOKING seals we get picture perfect functional seals. Thanks to Gaggia and his floating seal divider, of course. What was an economical solution to manufacturing the piston turned out to be an economical solution to resealing the piston.
This approach to sealing a piston, by the way, is simply a matter of economics, for two perfect seals could be made for the cost of the mold (thousands of dollars). So for quite a few thousand dollars less than the cost of picture perfect LOOKING seals we get picture perfect functional seals. Thanks to Gaggia and his floating seal divider, of course. What was an economical solution to manufacturing the piston turned out to be an economical solution to resealing the piston.
The second major functional system is the pressure control valve and drain system. On the earliest models this consisted of a pressure valve mounted on the boiler top with an encased counterweight and a tube which was routed directly down the side of the kettle to drain into the drip tray. This was later modified with a lower swivel arm to allow the user to move this tube out of the group area for better access to the group area.
This system is composed of numerous parts and seals and in this case the original chrome plated drip tube has been replaced with a functioning copper line.
The bottom swivel arm has an internal seal against the ball mounted in the upper cup.
The upper part contains the pressure regulation device and the threaded post which holds the cup against the boiler top and installs the unit as a whole.
The brass 1/8" BPP threaded fitting is installed with a spanner socket.
And fits together just so - with the cap placed on top, requiring a seal to direct the flow of steam downward into the lower swivel arm and drip tray.
When assembled and installed this proves a simple solution to overpressure control and steam/water draining from the top of the machine to the drip tray.
The brass 1/8" BPP threaded fitting is installed with a spanner socket.
And fits together just so - with the cap placed on top, requiring a seal to direct the flow of steam downward into the lower swivel arm and drip tray.
When assembled and installed this proves a simple solution to overpressure control and steam/water draining from the top of the machine to the drip tray.
After installing a small u-cup seal in the piston rod opening on the boiler top, the rest of the top parts can be installed. The boiler fill neck is threaded in place with a seal, the pressure valve is threaded in place with needed seals and the piston rod passes through its sealing cup. The entire boiler is held tight by the central assembly nut which also is the base for the lever system. You can see the 3 pin format for this system. This allows not only the lever to be secured in a minimum of space, but this system allows the piston to move up and down in the cylinder while maintaining the proper alignment within the cylinder. Also, the rod will travel vertically without deforming the rod seal by the application of horizontal forces. This is a very ingenious solution to this engineering challenge, but as you can see, one which required the manufacture of numerous specialized parts, no doubt adding much expense to the production of just the lever part of the machine. But since Achille Gaggia had his (and his backer's) fortunes on the line, this part of the machine was critical to the success or failure of his invention.
View with lever raised showing perfect alignment of piston rod. The rod seal is compressed by the top rod housing nut.
View with lever raised showing perfect alignment of piston rod. The rod seal is compressed by the top rod housing nut.
One outstanding feature of the machine is the addition of a simple dial thermometer to the machine....here as the top knob of the water fill cap. This was both a tremendous addition to a machine that had no apparent control functions, but also clearly marked at the temperature to produce Cream Cafe, for this was what Gaggia was promoting....not so much the machine as the espresso produced by the machine. This thermometer changes the entire machine in that it gives the user a clear level of control and mastery that does not exist without the thermometer. It really takes the operation of the machine to a much higher level and makes the use self explanatory. Perfect!
Drip tray grate with the big "G" pattern....another bit of showmanship and flair!
There can be no mistake who made this machine.
Drip tray grate with the big "G" pattern....another bit of showmanship and flair!
There can be no mistake who made this machine.
The 1948 Gaggia Gilda is sometimes incorrectly described as an open boiler gravity fed espresso machine. No so....it is a pressurized closed boiler machine, much in the same vein as the lever machines still in production and many other small format espresso machines. The Faema Faemina and LaCimbali Microcimbali use the same sleeve cylinder with open kettle design, though with a spring applied to the piston. The difference is basically the presence of a steam wand. Add the wand and the Gilda would be right at home in a modern consumer appliance show.....so why no steam wand? In working with the machine and thinking about just what Achille Gaggia was doing at the time we can only conclude that he was promoting Caffe Crema. Of course, he was also selling espresso machines but had met resistance to his new espresso coffee. Caffe Crema was not the instant hit as is sometimes described in the historical literature, since as with many things, it was not universally accepted . Imagine the Cafe owners looking at their new Verticale with 6 spigots and just what THEY thought of Achille Gaggia and his new invention. What did the espresso machine dealers and restaurant equipment suppliers think of Cream Caffe? One can project many sources of resistance to this idea. The coffee bars all used milk and sugar and chocolate to combat the bitterness of their steam extracted espresso, and the public were accustomed to this as well, both at the bar and in the home. So the Gilda would do one thing.....make Cream Espresso Coffee without the need of steamed milk to make it drinkable....it was just perfectly sweet as it was!!!! So to produce a machine with a milk steamer would have defeated the promotional purpose of the Gilda.....to spread the gospel of Cream Coffee far and wide......if the Gilda accomplished this mission and what part she played, we cannot say, but for all of his entrepreneurial genius and feats of design and engineering Achille Gaggia did indeed change the world.....of coffee.