How to Improve the Quality of the Rice Mill

The Best quality rice will be attained if

(1) the quality of paddy is good and

(2) the rice is milled properly. 

To improve the quality of the rice mill, the following factors should be considered: 

1. Paddy:

Mill at the right moisture content (MC)

A moisture content of 14% MC is ideal for milling.If the MC is too low, high grain breakage will occur resulting in low head rice recovery. Broken grain has only half the market value of head rice. Use a moisture meter to determine the moisture content. Visual methods are not accurate enough.

Pre-clean paddy before husking.

Use of paddy without impurities will ensure a cleaner and higher quality end product.

Do not mix varieties prior to milling.

Different varieties of paddy have different milling characteristics that require individual mill settings. Mixing varieties will generally lead to lower quality of milled rice.

2. Technology:

Use rubber roll technology for husking
Rubber roll huskers produce the best quality. Engleberg-type or “steel” hullers are no longer acceptable in the commercial rice milling sector, as they lead to low milling recovery and high grain breakage.

Use a paddy separator
Separate all paddy from the brown rice before whitening. Paddy separation after husking will lead to better quality milled rice, and reduce overall wear and tear on the rice mill.

Consider two-stage whitening
Having at least two stages in the whitening process (and a separate polisher) will reduce overheating of the grain and will allow the operator to set individual machine settings for each step. This will ensure higher milling and head rice recovery.

Grade the milled rice
Install a screen sifter to remove small brokens and chips from the polished rice. Rice with a large number of small brokens (or brewer’s rice) has a lower market value. The small brokens can be utilized to produce rice flour.

3. Management

Monitor and replace spare parts regularly
Turning or replacing rubber rolls, refacing stones, and replacing worn screens regularly will keep milled rice quality high at all times. 

How to Produce Good Quality Rice

To produce good quality milled rice, the paddy should be good, equipment well maintained, and the operator should have appropriate skills.

1.Good quality paddy

The starting quality of the paddy is should be good and paddy should be at the right moisture content (14%) and have a high purity.

2.State-of-the-art equipment

It is not possible to produce good quality milled rice with poor milling equipment even if the paddy quality is optimal and the operator is skilled.

It is evenly important to service and maintain the mill properly. The rice mill should always be clean and well maintained.

3. Operator’s skills

The mill should be operated by a skilled operator. An operator who is continually adjusting valves, hammering ducts, and screens does not have the required skills. Tell tales of improper mill operation are paddy in the rice husk exhaust, rice husk in the separator, brokens in the bran, excessive bran recovery, and under-milled rice. Training of operators in operation and maintenance of rice mills are crucial in improving rice quality.

If any of these requirements is not met, milling will result in poor quality rice. For instance, milling of poor-quality paddy will always result in poor quality milled rice, even if a state-of-the-art mill is used or the miller is experienced.

Similarly, the use of good quality paddy by a well skilled operator may result in poor quality rice if the mill is not maintained regularly. The losses in rice milling that can be attributed poor paddy quality, machine limitations, or operator innocence, is anywhere from 3 to 10% of potential.