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July 2013 Newsletter


Espresso machines have been around for just over a century, but in
that time there have been significant changes in how they work and
the beverages they produce. The very first espresso machine,
invented in Italy by Angelo Moriondo in 1884, and improved in the
early 20th century by Luigi Bezzera and Desiderio Pavoni, would
today be recognised as a "steam toy".

It worked by forcing boiling water under steam pressure (1 to 2 bar)
through the ground coffee. The resultant beverage was very similar
to that produced by a Moka pot or Atomic type brewer. Thick,
somewhat bitter, no crema.

It wasn't until 1948, when Achille Gaggia began manufacturing the
first spring lever machines, that espresso as we know it today
became common. Back then it was called "Crema Caffe", cream coffee,
and it was the crema that made spring lever machines successful.

A spring lever group is basically a cylinder with a rod, spring and
piston inside. Pulling the lever down raises the piston, compresses
the spring and allows water direct from the boiler to be drawn into
the space under the piston. The barista then releases the lever and
the spring forces the piston down, pushing the water through the
coffee at a pressure of 8-9 bar. Presto, espresso with crema! The
other major benefit of lever brewing is that the water cools down as
it expands into the cylinder, so suddenly a brew temp of 92C or
thereabouts is feasible. Presto, no more "burnt" coffee!

Levers have a number of limitations, including a tendency to
overheat in constant use and the barista developing one arm's
muscles out of proportion, but in capable hands they still produce
an unmatched shot. Lever machines didn't have pumps, simply relying
on town water pressure and a sight gauge for boiler refill. Heating
was controlled by big mercury switch pressurestats  and could be
electric or gas.

It took 13 years of development for the next big advance in espresso
machines to be revealed, and it was a doozy. In 1961 Faema
introduced the E-61 model espresso machine. It had a number of
industry changing innovations, starting with an electrically driven
pump delivering 9 bar pressure to the group.

Instead of drawing hot water directly from the boiler, cold water
was pumped through a heat exchanger inside the boiler and then to
the group. The group and heat exchanger formed a thermosyphon loop
which kept the group heated but below boiling point. The group
itself was a marvel of engineering, cams, rods, washers and springs
which allowed pre-infusion, precise shot flow control and post shot
pressure release.

There has been a lot of electronic automation and control added to espresso machines since 1961 but in my opinion the original Faema E-
61 machine was the single biggest advance ever made when it comes to
espresso equipment. The basic E-61 group and thermosyphon design is
still popular 50 years after it was released. Both consumer machines
(laScala and many others) and commercial machines (including Faema)
testify to the excellence of the original design.

This month's special coffee begins this year's supply of "new crop"
coffees.

Ethiopian Yirgacheffe Dumerso
$48.00/kg

It has a pronounced citrus flower and jasmine aroma, sparkling front
palate acidity with distinct berry fruit tastes, and a creamy,
smooth cacao finish.

Until next month

 Alan.