Why cooking times for rice are different in different locations

Question

When I learned to cook rice in the New Orleans area, I used the following recipe:

In a big sauce pan measure 1 cup long grain rice to two cups room temperature water, salt to taste.

Bring to a boil, turn heat down to simmer, cover with lid for 30 minutes and rice is done. Never use a spoon in rice, only a fork. This is the way I was taught and it worked perfectly every time.

I moved to Indiana and tried the same method, same rice brand, same water, approximately the same type of stove. Now I have to use more water and less cook time, about 20 minutes total, instead of 30.

I know that Indiana is more than 700 feet above sea level, and parts of New Orleans are actually below sea level. But from what I have read, you ought to add to cook time when at a higher altitude, not subtract.

What causes this difference? Is it really due to altitude? Perhaps relative humidity? New Orleans has a very humid climate, Indiana is usually much drier. Today for example, I checked and Indianapolis has 39% relative humidity, and New Orleans – 90%.

Has anyone else heard of such a difference in cooking times? I would like to see if there is any kind of table giving cooking times based on local climatic differences. Please confine answers/comments to either experience or research.

Answer 1

Humidity and altitude both can have very large effects on cooking times and methods, especially with methods that are moisture-sensitive, like baking, braising, etc.

In your case, since the altitude difference is negligible, the rice is probably being affected by the ambient humidity; in Indiana, the rice is in a less humid climate and will thus be drier; it will require more water than rice which is stored in a naturally wetter climate like Louisiana. The difference in cook time could be either due to a difference in your stove's efficiency in heating the water, or possibly due to drier rice being more efficient at absorbing water, I'm not sure (and can't find any real references either way).

I live in a place which is high in altitude (around 4800 feet/1460 m) and very dry (it's classified as a desert), so I have to heavily adjust any recipe involving rice, baking, etc to use more moisture and often cook longer (boiling rice I usually add about 25% more water and it takes about 25% longer, sometimes more, than the instructions specify).

Generally, if you move from one climate or elevation to a very different one, you have to experiment a little to figure out how to adjust for your specific circumstances.