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Is smart heat the smart equipment selection for your client’s
project?
As a member of FCSI,the news of many developments in foodservice
technology float across one’s desk.. FCSI members are
responsible for sorting out these new technologies to create an
ideal environment for preparing food which optimally satisfies
their client's specific requirements. I use many criteria in
determining what equipment best suits a given project’s needs,
size, initial cost, reliability, clean design, safety,
performance, operating cost, and overall user-friendliness.
My principal efforts are
devoted to developing the best-performing kitchen possible for
Friendly’s Restaurants – a regional 800 unit combination
coffee and ice cream shop chain. The operating realities of
Friendly’s are strongly influenced by high turnover labor
pools, pressure to reduce operating costs and a desire for
increased cooking process simplicity, consistency, and
reliability in the smallest possible area.
In the past, the
past, the foodservice industry has made great strides toward the
better engineering of various menu products (i.e.,consistent
frozen paties, unique processing, innovative packaging, and a
wider variety of taste and texture choice), so it seemed
appropriate to reconsider the engineering of the appliances used
in the final preparation stages of these imporved items. Of
Friendly’s 800 kitchens, in excess of 700 are all-electric,
with the old GE griddle the accepted standard in most.
Griddle technology has remained stagnant for years, with only
enhanced controls,better construction meterials, and better heat
distribution as developments of any significance. Unfortunately,
the major equipment "enhancements” brought with them
higher costs and more complexity. In spite of feedback from
restaurateurs for new cooking equipment addressing their most
pressing issues, there have been no significant operational
breakthroughs.
However, a new
grill heat transfer technology developed by Metcal,Inc. Brings
some fresh tidewater into the
food service sea. Before I describe this new development,
I’d like to explain why I feel that the present conventional
all-electric thermostatically- controlled griddle technology
is inadequate.
Testing of the
classic GE electric griddle revealed the following results:
1)
The typical temperature variation within the prime
central cooking zone exceeds 110ºF during a typical full load
cooking cycle (thermal regulation exceeds +
50º F}.
2)
Cooking
consistent product (the same mass of product with the same bulk
temperature, at the same grill location to the same level of
doneness) requires a widely variable rate of power consumption
from batch to batch. A range of between 0.15 and 0.35 Kw was
consumed for the identical thermal mass batches under similar
operating conditions.
3)
A temperature
variation of 76º F within a central cooking area is experienced
under non-load conditions (thermal regulation exceeds+ 38ºF).
4)
For an identically timed cooking cycle, a frozen
quarter-pound hamburger may be grilled to rare, medium rare, or
medium within the same batch of patties. Even worse, consecutive
batches may range from rare to medium well.
The positioning of the heating elements and the thermostat sensor
controlling their performance cause these variations. It’s an
inherent problem in every conventional griddle- gas or electric.
In addition to the above concrete results, I have postulated three
conclusions:
1)
Griddles which perform well on one criteria sacrifice
quality on another.
2)
For some
criteria, like temperature consistency, none perform ideally,
and there is only a choice from the “lesser of two evils”
–poor sensitivity and dynamic response or high thermal
gradients.
3)
Although
manufacturers have come out with various bells and whistles such
as digital controllers and easier to clean surfaces, these have
provided little change in overall performance cooking
consistency, especially when one factors in variable demand
(time of day and product mass).
After re-examining Friendly’s griddle performance profile and
literature describing Metcal’s patented design features,
I elected to visit Metcal, Inc., in Menlo Park, CA, to test
their new “Smart Heat” Convertible Grill. After some initial
wariness, I discovered that this grill really offers some new
features, innovative concepts, and sound solutions. For example,
after the grill is turned on, it reaches operating temperature
in only two minutes.
There are no thermostats, sensors, or heating elements, yet the
grill surface maintains consistent temperature +3 F within 2”
of the edge of each cooking zone at idle.
How is this
superior performance achieved?
The Metcal proprietary heating technology is simply based
on physics principles that are over 50 years old, yet is
radically different from any technology used in the foodservice
market today. Metcal has unleashed the physical properties of
the grill surface itself
to self-regulate around a designed-in temperature. This concept
has been used in commercial electronics, medical equipment, and
soldering systems for a decade.
Unfortunately,
their self-regulation principle is not as readily described as
operating the grill. Simply stated, the Metcal Convertible Grill
is based on the principle that magnetic material will self-heat
when placed into and inductive field. The more magnetic the
material is, the faster the heating, and conversely, the less
magnetic it is, the slower the heating.
Metcal’s unique
grill surface changes its magnetic properties by itself. When
the grill surface is below the desired set temperature (Curie
Point) it is highly magnetic and instantly draws power only to
those spots not at the set point. As the surface approaches its
predetermined set temperature, the material becomes less
magnetic and stops heating entirely when the Curie Point is
reached. As a
result, when a load is placed onto the surface, it instantly
starts recovering (drawing power) and once at temperature stops
drawing power. It can’t create a hot spot as only cold regions
draw energy. This means that it is physically impossible to
overdrive a properly constructed Metcal grill plate!
This self-regulating
effect is one of the physical properties of the ferromagnetic
alloy that makes up the grill surface. It is not driven by
controllers, thermostats or any other device. In fact,the Metcal
system has the fewest mechanical parts of nay marketed system.
In place of the usual complicated elements, sensors,and dials,
the Metcal Grill consists of a
power supply, a power switch, an inductive coil, and the
grill plate itself. If simplicity is grace, the Metcal system
seems graceful indeed.
This inherent
simplicity leads to may advantages over existing griddle
designs. Cooking consistency is improved since the grill
maintains a truly consistent surface temperature profile over
the entire surface when under full, random, or no-load
conditions. This is accomplished without any sensors requiring
calibration or adjustable dials and switches to set. While
cooking, obtain greater effective cooking area from the
consistent temperature profile edge
to edge.
Because each plate can have its own set point temperature, separate
cooking zones are created without any temperature profile
migration, providing flexibility for multiple item menus. Power
consumption is dramatically lower because power is drawn only
where and when it is needed, with thermal efficiencies ranging
between 75%-85%. And, when the day is over, clean up is easy
because elimination of hot spots means less burned on fat and
carbonized material. The grill plate is portable and may be
carried to the dish machine if desired.
Test Results:
1)
The typical temperature variation within the prime
central cooking zone is less than 30˚F during one cooking
cycle (thermal regulation is less than 15˚ F).
2)
Cooking
consistent product (the same mass of product with the same grill
location to the same level of doneness) requires between 0.14
and 0.15 Kw per batch; a more consistent rate of power
consumption than the competitive thermostatically controlled
electric resistive element models.
3)
A
temperature variation of only 3˚F within a central cooking
area is experienced under non-load conditions (thermal
regulation is less than 2˚F) This is 36˚F superior to
the current industry standard.
4)
For an identically-timed cooking cycle, a frozen quarter
pound hamburger will always reach the same level of doneness.
Convertible technology does achieve this consistency.
In the future, Friendly’s will be doing extensive testing of a new
Metcal “Smar Heat” Convertible Grill in our R & D test
kitchen. If this extended test continues to confirm the inetal
results of better food consistency, it will be a key element in
Friendly’s Kitchen of the ‘90s design activity and
presumably make a significant impact on our industry.
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