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Grain Composition and Physical Attributes | Cooking and Eating Characteristics

Size and Weight

The length and width of a rice grain are important features that determine the class of the rice. There are three main classes of rice, based on grain length: short, medium and long. In terms of width, arborio grains are generally the widest, followed by short, medium and long grain varieties.

The ratio of length to width is used in international trade to describe variety shape.
Grain length and width are important because:
· all rice grains of a particular type must be uniform.
· new rice varieties must fit into one of the three length classes
· during packaging in the short term, new rice varieties will be mixed with the varieties they aim to replace so must not be shaped differently.

Grain weight provides additional information about the size and density of the grain. Grains of different density are likely to retain moisture differently and cook differently. Uniform grain weight is important for consistent grain quality.

Length and width are measured on brown rice and grain weight is measured on paddy rice.

The Grain - Size and Weight
Rice Class
Length (mm)
Width (mm)
Length/Width
Grain weight *g
Short - Japanese style
5.2
2.9
1.8
25
Short - pearl
5.3
3.0
1.8
30
Medium
5.9
2.8
2.1
28
Arborio
6.3
3.3
1.9
32
Long - Australian style
7.5
2.1
3.5
25
Long - firmer cooking
7.4
2.2
3.4
25
Fragrant - jasmine style
7.5
2.2
3.4
25
Basmati style
7.0
2.2
3.2
25
Waxy
5.3
3.0
1.8
30
Purple
variable
variable
variable
variable
Saki
5.3
3.0
1.8
26

* Grain weight is measured by weighing 1000 paddy grains with a moisture content of 14%.

Text and images adapted from the publication "Production of Quality Rice in South Eastern Australia" (Chapter 13) with the permission of the Rural Industries Research and Development Corporation (RIRDC). Acknowledgments to: Dr Melissa Fitzgerald, Warwick Clampett, Lucy Kealy Pty Ltd and the Irrigation Research and Extension Committee (IREC)

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