Why Does Brown Rice Take Longer to Cook Than White Rice ?

Brown rice takes longer to cook than white rice because it is still has bran and germ layers intact in the rice. The bran and germs contain fiber, oil and many nutrients, which makes the brown rice denser in texture and longer cooking timing. The bran and germ layers is typically tough and fibrous and it acts as a barrier to water absorption. It means that when cooking brown rice, it takes longer time for water to penetrate through the bran and germ layers and reach the starchy endosperm inside the rice grain ( when water reach the starchy endosperms the grain, the starch inside the grain gelatinize and absorb water, causing the rice to swell and become tender). In addition, Brown rice is chewy and tough texture because the fiber in brown rice, primarily found its bran and germ layers, does not soften completely during cooking due to its complex and resilient texture. Fiber is made up of long chains of complex carbohydrate that are resistant to breakdown by heat and moisture.

some of the fiber in brown rice may soften slightly during cooking especially with prolonged cooking time, if the rice is soaked before cooking. However, the fibrous structure of the bran layers generally remain intact. The inability of fiber to soften completely during cooking is why brown rice retain a chewer texture compared to white rice. 

In contrast, white rice has had the bran and germ layers removed the processing, which not only shortens the cooking time, but also result in lighter texture of rice, without bran and germs white rice grain absorb water more easily and cook faster. However, the bran and germ layers are not removed from the brown rice during processing due to preservation of its nutritional content.

These layers are rich in dietary fiber, antioxidant, B vitamin and healthy fats. Removing the bran and germs layers from the brown rice would reduce its cooking timing and lighter texture similar to white rice, but it will also significantly diminish its nutritional value, but retaining these compounds makes brown rice healthier portion as compare to white rice.

Terminological system

• Endosperm: Endosperm is a tissue found in seeds of flowering plants, serving as a nutrient reserve for the developing embryo. It typically contains carbohydrates, proteins, and other nutrients essential for the germination and initial growth of the plant embryo.

• Complex Carbohydrate: A complex carbohydrate is a type of nutrient found in foods like grains, vegetables, and beans. It's made up of long chains of sugar molecules, which take longer for your body to break down compared to simple sugars. This slower breakdown provides a steady source of energy and helps you feel full for longer periods. Examples of complex carbohydrates include whole grains like brown rice, oats, and whole wheat bread.