What is the point of a salt mill?

Question

Salt mills and pepper mills often come in pairs. I understand the purpose of the pepper mill: It breaks open the pepper corn and releases the aroma. But there is, to my knowledge, no such thing as a salt corn, at least on the macroscopic level. So what do I gain by grinding the salt at the table or at the stove instead of just buying the smaller version to begin with? I understand that there are different kinds of salt, but it seems they ought to be independent of the size of the bits.

Asked by Peter Eisentraut

Answer

Trying to get to the bottom of the issue, I decided to take a few pictures of a few different types of salt. The pictures shown below were taken by me and are all proportional (the camera was the same distance away from each type of salt, so you are getting an accurate size comparison).
The picture illustrates my suspicions, which is the difference is the surface area (ignoring of course mineral content and different types of grinding salt). Standard table salt is a compact little cube, effective when it’s to be dissolved in a liquid, but not so much when it comes to direct contact with the taste buds. Place one cube on your tongue and you get 1/6th of the surface area in contact, meaning, a lot of salt without much saltiness. Sea salt, with a more rectangular shape is closer to 1/4th the surface area touching your tongue. Ground salt is more like shards of glass, so nearly 1/2 of the exposed area could be in contact making things taste that much more salty. Also with a much finer texture, you are left with many more particles in a wider area, meaning, saltier with less salt.
It’s a good way of finishing a dish when the salt is going to be lightly dusted on top or mixed with an oil where it will not dissolve at all. When you are dissolving it in a liquid, it really makes little difference which type you use. When it comes down to it, it’s all about how picky you want to be with it.

Answered by FoodTasted

Check more discussion of this question.