Baking & Snack - November 2020 - 88

OVENS

Convection ovens are
often easier for changeovers because they only
use one burner per zone,
or up to six in a 300-foot
cookie and cracker oven.
Reading Bakery Systems

giving it a natural, baked flavor, " he explained " It's like
putting that hot dog over the campfire where you get the
intense heat. It always tastes better because you're getting those reactions on the surface versus just putting it
on the stove in your home. "
Convection energy then pulls moisture out of a product the most efficiently.
" By putting initial zones of DGF for flavor development, followed by the remaining zones for convection for the efficiency of pulling the moisture out of
the cracker, you're getting the best of both worlds, "
Mr. Zvoncheck said.
Effective heat transfer is critical to the baking process.
Mr. Barnes observed that proper application of convective heat transfer quickens bake times at lower overall
temperatures. That combination leads to more moisture
retention and less bake loss that can improve quality and
extend shelf life.
For operating versatility, Ken Johnson, president,
Gemini Bakery Equipment, pointed out that Gemini/
Werner & Pfleiderer's indirect-fired tunnel ovens feature " true turbulence " that can be incorporated into each
oven zone. The turbulence in each zone can be independently adjusted via variable-speed blowers configured to
blow from top-to-bottom or bottom-to-top, depending
upon the product. The oven also comes with radiant or a
combination of radiant and convection heat.
" This turbulence feature provides for a uniform bake
color and elimination of white under-baked sides on
pan bread, " Mr. Johnson said. " Bake temperatures and
times are reduced with the use of turbulence zones due
to the higher heat transfer efficiency of convective heat. "
In an Auto-Bake Serpentine convection oven, the

air speed directly impacts the heat flux. Scott McCally,
president, Auto-Bake Serpentine, a Middleby Bakery
company, noted the fans act as the mechanical force that
increases the rate that the heat is driven into the pans
and products.
" For most product baking profiles, a high fan speed in
zone one is desirable to quickly get the pan temperature
up to setpoint, " Mr. McCally explained. " As the products move through zones, there is a gradual transition
from predominantly bottom heat to predominantly top
heat. As that transition occurs, the air speeds often slow
down, so the product is hit with a more subtle force. "
By adjusting the oven's airflow, Mr. Zvoncheck said,
RBS balances the vertical heat to control the cracker's
top and bottom color, while keeping the cracker lying
flat on the oven belt. To create a variety of snacks, RBS
Smart Zone technology combines convection and radiant heat in each zone.
" We're covering all of the bases with this Smart Zone
technology, " he said.

Timely transitions
Adjusting oven temperature depends on various factors.
In an Auto-Bake convection oven, Mr. McCally said, the
transition time between temperatures of +/- 30ËF and
less can be achieved in fewer than 5 minutes. The size of
the zonal package burners along with large exhaust fans,
which bring in a high volume of cool ambient air when
necessary, reduces oven temperature quickly.
Brent Grantham, national account manager,
Middleby Bakery, suggested that some baking profiles
can change almost instantaneously by focusing more
on Btu input than temperature to optimize oven per-

THE ONSLAUGHT
OF PRODUCT
INNOVATION
COUPLED WITH THE
PROLIFERATION
OF VARIETIES TO
MEET CUSTOMERS'
CHANGING NEEDS
HAS PROMPTED
BAKERS TO EXPLORE
NEW TECHNOLOGIES.
88 Baking & Snack November 2020 / www.bakingbusiness.com

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Baking & Snack - November 2020

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