Jim Gallas, a physics professor
at the University of Texas at
San Antonio, and Gerry Zajac, an
industrial physicist and adjunct
faculty member at the University
of Illinois at Chicago, may be
revolutionizing the coffee
brewing process with their newly
patented coffeemaker. The "Just
Right" coffee brewer brews
coffee to precisely the desired
strength and color using an
electronic sensor and feedback
system.
"The idea is to use a light beam
to monitor how dark the coffee
is," says Gallas. A red light
beam on the right side of the
coffee maker's housing unit
shoots across the bottom (at
about the half-cup to one-cup
marker) of the glass carafe it
cradles. On the other side of
the housing unit is a light
detector, measuring the
intensity of the light. "It
produces a photovoltage," says
Gallas. "The brighter the light,
the higher the voltage and the
weaker the coffee."
At the beginning of the brewing
process, the first few cups are
considerably darker than the
remaining to process, so the
intensity of the red light beam
getting to the detector is low,
as is the voltage. As the
brewing continues, the coffee
gets lighter, the beam gets
brighter, and the voltage goes
up to the point that's been
preselected. Once it reaches
that point, the brewing process
ends.
If you put in too few grinds for
the number of cups you wanted to
make - instead of making eight
cups as you intended - it
[coffeemaker] might make six
cups, but it will give the same
color," says Gallas. "It will
always come to the darkness that
you have selected. So you play
around with it and use a couple
of settings until you find one
you like."
The machine also monitors the
oxidation level in coffee after
it's been brewed. Once the
process is completed, all 10 LED
lights in the front of the
machine are lit. After coffee
sits for 15 minutes to a
half-hour, the lights begin to
turn off, one by one, indicating
that coffee is darkening or
oxidizing.
Gallas and Zajac hope to license
their Just Right system to a
large company or start their
own. According to Zajac,
companies that make large -
volume coffeemakers are
particularly interested because
the "Just Right" helps avoid
waste.
Gerry Zajac and James Gallas
invented a system that monitors
the darkness of coffee to get it
"just right".
It's not something that kept him
up awake at night, but Gerry
Zajac, M. S. '74 UIUC, an
industrial physicist and adjunct
faculty member at UIC, spent
much of his spare time over the
last six years developing a
better coffeepot.
Gerry Zajac and colleague James
Gallas, a professor of physics
at the University of Texas at
San Antonio received a US patent
for a coffeemaker that brews
coffee to precisely the desired
strength, using an electronic
sensor and a feedback system
they believe will add only about
$10 to the cost of coffeepots.
Manufacturers are looking at the
prototypes right now, said Zajac.
Companies that make large-volume
coffee makers are particularly
interested because the system,
which the inventors call "Just
Right" helps avoid waste.
The system uses a harmless beam
of red light passing through the
brewed coffee to monitor the
darkness of the beverage.
The darkness of the coffee when
it is first brewed indicates the
strength of the drink, said
Zajac, and the darkening
continues as the coffee sits in
the pot. User's would experiment
with the coffeemaker setting to
find what strength of coffee
they want to produce.
When Zajac and Gallas applied
for a patent, they discovered
that the idea of monitoring the
strength of coffee with a beam
of light was not new. But their
device is the first to use a
light-emitting diode, a small
and efficient light source not
available to the earlier
inventor of 1970s.
Zajac said the project started
as 'kind of a lark" when he and
Gallas were sitting around the
kitchen table at Gallas' house
one evening. They were imagining
what household appliances might
do in the future when
manufacturers incorporated
microprocessors. They realized
that a system to monitor the
optical absorption of coffee, or
its darkness, and shut off the
brewing at the desired level,
would be very simple. To prove
it, Zajac built a model at home.
There is an unexpected benefit
to his coffee research, said
Zajac - he has learned how to
make a really good cup of
coffee. Coffee starts to oxidize
and acquire a stale taste as
soon as it is brewed; keeping it
warm in an open carafe hastens
this process. Zajac now puts his
coffee in a sealed thermos and
warms a cup in the microwave if
necessary, he said.
