Wheat, Durum Milling, Flour classes and varieties

Wheat, Durum Milling, Flour classes and varieties

Wheat (Gehun) is used to make Atta (Bread flour), Maida (All purpose flour) Dalia (cracked wheat), Sooji (Semolina)

Wheat has been used in India for over 5,000 years. Wheat today is not the wheat grown up to 1970s. The wheat has gone through major evolution. First major change occurred during 1960s (The Green Revolution What was the Green Revolution?) when existing species was changed to 'Sharbat Sonora' dwarf species. Later on Durum was introduced. Today there are two basic varieties of wheat produced in India to make Atta: Durum (Triticum durum Desf.) and Aestivum (Triticum Aestivum L). Aestivum is a semi hard wheat compared to hard Durum. For discussion, I will refer to Aestivum as Gehun. In India, about 90% of Atta is made from Gehun. Durum is also called Semolina.

Durum is harder than any variety of Gehun. In United States Durum is  used to make Pasta products (Spaghetti Macaroni), and short patent bread flour.

Wheat

The wheat is categorized by it's hardness. Durum is the hardest. Gluten gives the dough its elasticity ('Loach') and ability for yeast to work efficiently. Harder the wheat, higher is its protein content, and potential to produce gluten. For discussion, we will just categorize wheat as Soft, or Hard and Durum.

I can not resist mentioning a 'cultural' thing in India. Wheat color ranges from creamy white to to reddish tan. In the olden days, the parents of a boy were always looking for a bride whose complexion was 'Wheat-ish' resembling color of soft wheat grain.

Structure of wheat grain

After, the husk is removed, the wheat grain is revealed. It has three layers. The outermost layer (the skin of the grain) is called 'Bran' and represents about 15% of the grain, followed by 'Endosperm' representing 82.5% an then the inner most called 'Germ' representing 2.5%. Technically, The bran consists of two layers, but we will just call it bran.

Bran is basically fiber, endosperm is starch, and germ is the protein

Wheat Classes

In United States, the wheat is divided into six classes:

Hard Red Winter, Hard Red Spring, Soft Red winter, Hard white, Soft white, and Durum

In United States, Spring wheat (hard, soft, and durum) are planted in spring and harvested in summer. The winter wheat are planted during fall or winter. In India, spring wheat may be planted in fall.

The white wheat lacks the red gene present in the bran of red wheat. The red gene gives a slightly bitter taste. During 1950s, when India imported the wheat from United States under PL 480 deal, it was Hard Red wheat. The red gene in the bran made the flour was slightly more bitter and harder than the local hard red wheat. Locals cut it with native wheat to make it more palatable for Indian taste.

 In India Hard red, Hard white,  and Durum are used to make Atta. Soft white is used to make Maida and Pastry flour. The hard wheat classes are really semi-hard in comparison to Durum.

Milling

Household Chakki

In the olden days, I remember every household had a Chakki to mill the wheat. It consisted of two stone disks, each about 20" in diameter, and 3" thick. The bottom disk was stationary, the top disk is rotated to ground the wheat. The top disk has a hole to feed the wheat. As the top disk is rotated, it scrapes the wheat spreading it out to the outer edge. The scraping surface of both the stones is corrugated. The top disk sits on a spindle located on the bottom disk. The different length spindles are used to determine the coarseness of the output. The output is sifted to obtain different varieties of the product.

Chakki Milling/Stone Milling

Chakki milling in India is almost same as Stone milling in the western world. The basic basic principal of Stone milling is same as the Household Chakki milling. There are enhancements like automatic control of the spindles to adjust space between the disks. The process results in 15% to 17% starch damage and no loss of Ash.

Roller Milling

There are three sets of rollers, each consisting of two rollers and associated sifters. The first set of rollers has corrugated surface, one moving faster than the other causing the brown skin (bran) of the wheat grain to be sheared away. The out put is than sifted. After the bran has been removed, the output is passed through two more sets of rollers and sifters  to separate germ and finally producing flour. Normally, this results in 5% to 6% damage to the starch and loss of Ash. In India, the corrugated surface of the first set of rollers is designed to actually crack the wheat grain and NOT just shear it. This technique results in comparable starch damage