I need to have a scientific explanation of why rice cooks faster in plain water than water containing sugar. I know the sugar interferes with the gelatinization of the rice, but I would like a scientific explanation - such as how the elements within the rice respond to the water with sugar in it to interfere with the gelatinization.

  • Can you describe your rice cooking method? Feb 9 '16 at 6:16

I had some fun with this one. To start: Gelatinization is when the intermolecular starch bonds break, see Starch Gelatinization

I originally thought it had to do with the sugar changing the boiling point of the water. I thought this would increase cooking time, but turns out that's wrong. A higher boiling point means the water can get hotter before turning into water vapor. Therefore shortening cooking time. The mystery continues.

Under the last paragraph in section 8.2 of Thermodynamics of Water it talks about impurities.

Shortly after that I found help in this paper Effects of Sugar on Starch Gelatinization. It says that there are two reasons that I'll summarize here. 1) Sugar bonds with the water making it less available to bond with the starch. This makes it so that the water needs to be hotter to bond with the starch. 2) The sugar bonds with the starch holding them together a bit longer.


The rice soaks up the boiling water by transferring water into it's cells and absorbing the moisture into it. We boil it in water so the rice softens and is warm instead of a distasteful cold. The sugar interferes with this process and since it is not water being absorbed into the rice and a more dense fluid being absorbed by said rice then takes longer.

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