Cleaning and Tempering of Wheat
06 February 20145 min reading
“If the wheat is milled directly without being tempered, it can be cracked like boiled and pounded bulghur as well as the non-separation of the bran or bran’s being milled with the wheat. As a result of this situation, the flour has a grey (darker) color. The importance of the tempering process occurs at this point.”
The most important thing in milling is cleaning and dampening the wheat by classifying according to its color and hardness. Wheat has to be processed into different cleaning machinery to separate it from foreign substances such as stalk, halm, stone, sand and black grain.
These processes are specified as following: separating the incoming raw material from the ones bigger than wheat (stalk, halm) and separating the ones smaller than wheat (sand, black grains) in the Waste Separator. After this by using Air Passage, Radial Tarar and Waste Separator, the thin substance is separated from the wheat. Then, a mixture of small and big stones brought with the incoming wheat is separated in a Dry-Stoner. In a Husk Peeler wheat and its husk is rubbed and particles of dust have been cleaned from the wheat after all the substances separated from wheat. Then, again wheat is processed into Air Passage and Radial Tarar to separate the husk from the wheat. Following the separation; the big black grains are separated in a Small and Large Grain Trieur machine; the long grains are separated in Long Grain Trieur machine.
Following the cleaning process of the wheat, it is transferred to the intensive dampener machine via an elevator in order to temper the wheat. The new intensive dampeners have 3 rotors and provide a better water distribution process to temper and blend it. This process is the first tempering process in mills. In first tempering process, the stand by time is depends on the class of the wheat (white or red wheat). For example, in white wheat stand by time is changing from 8 hours to 10 hours, but in red wheat these time increases to 15 hours to 20 hours. After first tempering process the moisture of the wheat is calculated. And this moisture has been fixed to the 15.5% to 16% in the wheat, 16.5% to 17% in red wheat. Then by using an elevator, the wheat is transferred to second tempering process.
The difference between these two tempering processes is the time of stand by. For the white wheat this time is 5 to 8 hours, for the red wheat the time is 8 to 10 hours. In the second tempering process, wheat is also processed into intensive dampener. It would be effective for preventing the formation of cracks to take the wheat into the B1 roller when its husk is still wet before being rested too much.
Also in tempering process, the stand by time and tempering time of the wheat of biscuit, which is white and soft, can be decreased. In red and hard wheat tempering time could increase to the 48 hours.
The tampering period of durum wheat (pasta wheat) varies 10 to 15 hours in the first tempering process and 5 to 6 hours in the second tempering process. As it is very important to separate the black heads from the grains like pasta wheat, barley and oat; Long Grain Trieur should be used for cleaning.
IMPORTANCE OF TEMPER
If the wheat is milled without tempering, it can be cracked like boiled and pounded bulghur or the bran is milled with the wheat. As a result of this, the flour has a grey (darker) color. The importance of the tempering process occurs at this point. In tempered and waited wheat, the husk is softened with the help of the water that had been given to the wheat, then the moisture is penetrating to the heart of the wheat. This helps the change in the wheat color and the process of separating from the husk grains speed.
The wheat that has been rested and tempered enough in first tempering process is mixed separately before the grinding process in order to separate the husk completely in the husk peeler machine; then it is rubbed and the dust particles are cleaned from the wheat. Air passage and Radial Tarar is used to separate these particles from the wheat. This process prepares the transfer of the wheat to the milling process.
MIXING OF WHEAT
In mixing process, the gluten, sediment and index rates of wheat has been calculated. These values average must be as stated below;
Wet gluten (min) : 27
1st sedimentation (min) : 26
2nd sedimentation (min) : 30
Index (min) : 70
Realizing the mixing process after the second tempering process is very important as the moisturizing and mixing processes can lead a big disequilibrium in moisture rate when it is done after the first tempering process. One type could be very soft and the other type could be very hard. Another important point also is that the wheat, which is being milled after the first tempering process would result a decrease in the quality of flour if the values that have been stated above are not equal before the mixing process.
Whereas the mixing process that is done after the second tempering process helps to hold the values stable and if there is a change in these values, the mixing values could be regularized easily to keep the quality of the product the same.
In modern flour factories, it is seen that filter using has started to be preferred more each passing day. Because the articles are thrown out the chimney, the cyclone system that has been used before hand is polluting the environment. The usage of the filter has an important role in environment protection and in the establishments. Filters hold the particles and small parts, which come from the cleaning machinery and vacuumed by an aspiration, in particle bags. This is the best system that should be preferred for the hygiene in the establishments in order not to give harm to the environment.
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