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Name: Stephanie
Status: educator
Age: 30s
Location: N/A
Country: N/A
Date: 7/28/2003


Question:
There has been a debate about the reason many people put uncooked rice in the salt shaker. Most will answer that the rice will absorb the atmospheric moisture instead of the salt so that the salt will not cake. I have trouble believing that rice is more likely to absorb moisture in the air than table salt. I believe the larger rice grains more likely "knock" the lumps out of the salt when it is shaken, rather than keeping the salt from absorbing water. So, what is the answer?


Replies:
Stephanie,

I think both sides of the argument are correct. Indeed, the grains of rice will tend to "knock the lumps out of the salt." So would small glass beads. However, the porous starch structure of well dried rice is also very attractive to moisture by virtue of hydrogen bonds that can form between water molecules and the -OH groups in the starch matrix. Thus, dried starch grains make a fairly decent desiccating agent.

Regards,
ProfHoff 713


Never really thought about this but your explanation makes sense. Rice does not readily absorb water. That is why you have to cook it for 10-20 minutes in boiling water -- so it would not seem to be very hydroscopic, does it? I tend to agree with your mechanical interpretation. You notice when you dissolve salt in water that the solution is hazy, that should not be. But if you look at the list of ingredients on the box you will find silica gel or aluminum silicate added (to prevent clumping). These fine particle powders DO absorb water and act as anti-caking agents.

Vince Calder



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