World Grain - August 2021 - 64

TECHNICAL PROFILE
Dampening's
importance in wheat milling
Process provides optimum moisture level to grain before the grinding process
By Önder Seker
D
ampening is an essential part of the wheat milling
process. Impacting flour quality and endosperm
extraction, an effective dampening operation
helps millers achieve better results.
The process of dampening, also referred to as tempering
or conditioning, is an important process in grain
milling that is used to provide the grain's optimum
moisture level prior to the grinding process.
This optimum moisture can
be defined as: " the bran being hard
enough to be separated from the endosperm
easily, and the endosperm
being soft enough to be milled
properly. "
The process plays an important
role in milling yield and
bread-making quality of the
flour. It ultimately helps to adjust
the flour moisture content
as well, which has a significant
impact on profitability.
How does it work?
The fragile wheat bran tends to
crumble during milling, making
its separation from the flour
harder, ultimately reducing the
quality of the flour. The dampening
process allows the endosperm
to mellow and soften
and the bran to gain elasticity
so that they can be easily
separated.
When wheat moisture is
above the optimum level, it
will be difficult to separate
the bran and endosperm during
milling and sifting due
to their increasing cohesion
and stickiness.
64
If the moisture is lower than optimum, the bran and
endosperm become easily crumbled. Although a higher
amount of flour is obtained, it is of lower quality.
In optimal dampening conditions, the bran can be
observed in bigger, flake-like particles during milling,
and it is easily separated during the sifting operation.
How dampening is applied
The dampening process includes two main stages. The
first is bringing the moisture content of the wheat to
the optimum level by adding water or, in some cases,
extracting water.
The second stage is the resting period in dampening
silos for a certain time to allow the absorption of the
water and spreading it along the entire wheat kernel.
The water must have enough time to penetrate the kernel,
which is called " dampening time. "
Grain dampening is considered a hydrothermal process.
The three main factors affecting the dampening
process are: water amount, temperature, and time. The
final flour moisture should not exceed 14.5%, otherwise
flour quality will be negatively affected during storage.
Water amount
Water significantly impacts the efficiency in milling
and sifting. The optimum level of moisture before
the grinding process varies depending on the type of
wheat. The ideal moisture levels prior to milling (at the
first break) are given in chart 1 (see page 65).
In dampening, generally 5% to 8% water is added
to the grain, especially for hard wheat. Since it is not
possible to add it all at once, the process is completed
in two stages.
The maximum amount of water that can be absorbed
by a grain corresponds to 40% of its weight.
Alapala's Automatic Dampening Machine (TOCA)
measures the grain's moisture content, temperature,
flow rate, and specific gravity and calculates the
required amount of water automatically.
August 2021 / World Grain / World-Grain.com
Photos courtesy of Alapala
http://www.World-Grain.com
World Grain - August 2021

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