There’s a lot of talk about how much salt Americans eat these days – and how much they shouldn’t.

But how about what kind?

Making the most of the ever-expanding array of salts on grocers’ shelves involves learning a little about chemistry (though just a little) and giving up on the idea that more money buys more taste. To consider:

Salt’s importance goes well beyond saltiness. It enhances the flavors of other foods, especially anything sweet, such as chocolate, says Chris Kimball, founder and editor of Cook’s Illustrated magazine.

In fact, he says one of the most common mistakes made by home cooks is undersalting food, perhaps a result of the mistaken notion that not adding a half-teaspoon of salt to a pot of soup is a meaningful way to reduce sodium.

It’s probably not. Just 11 percent of the salt in the average American’s diet comes from salt added at the stove or table. The rest comes mostly from processed and restaurant foods, which is why the American Medical Assn. recently called for those industries to halve their salt levels during the coming decade.

Ounce-for-ounce, salt is salt, whether standard, inexpensive table salt mined in the United States or pricey sea salt hand-harvested from French marshes. That changes once you start measuring by volume.

Because coarse grains create air pockets, a tablespoon of kosher contains less salt than a tablespoon of table salt. Volume measurements must be adjusted accordingly. Generally, multiply the volume by 1 1/2 when substituting kosher for table salt.

Chemically, all salts are much the same – at least 97 percent sodium chloride. Salts also contain trace minerals, such as magnesium. Sea salts can have these in higher (though still minimal) concentrations.

In fact, many sea salts are sold on the basis of their trace minerals. This is what gives many of them their unusual colors and – some companies claim – superior taste. The latter is debatable.

According to Robert L. Wolke, a chemistry professor at the University of Pittsburgh and author of the book, “What Einstein Told His Cook,” mineral concentrations in salt are so minute they don’t contribute any meaningful taste.

Sea salt companies may brag about their minerals, but the reality is that no matter how “unprocessed” a salt is, the simple act of evaporation (whether by wind, sun or machine) purifies out most minerals, he said.

While the higher mineral content in sea salts could lend subtle flavors differences when tasted raw, Kimball says those flavors would be indistinguishable once the salt is added to food.

Which leaves texture and size. Because these characteristics determine how well salt grains adhere to food, how they dissolve on the tongue and how quickly they deliver a shot of flavor, they are what determine when and how a salt should be used.

Finely ground salts, such as table and some sea salts, dissolve well and aren’t substantial enough to provide much noticeable mouth feel (such as crunch). They are best used in cooking.

Coarse salts, such as most sea salts, adhere better to food, dissolve more slowly and (when sprinkled on food just before serving) can provide a pleasant texture. They are best used at the table. Seasoned salts also fall into this category.

“If you spend a lot of money on a fancy French sea salt and you add it to a pot of soup that’s going to simmer for two hours, it’s going nowhere,” says David Kamen, chef instructor at the Culinary Institute of America in Hyde Park, N.Y.

The exception to these guidelines is kosher salt, which has large grains, but is equally popular for cooking and table use. Its size makes it easy to grab a pinch for seasoning during cooking. It also is much cheaper than most sea salts. (Kosher salt comes from the same sources as table salt, but is processed differently and generally lacks additives such as iodide.)

Here are some basic guidelines for using salt at the stove and the table:

¢ Table salt works equally well in the shaker and in cooking, though it lacks the textural appeal of sea and kosher salts. It generally is preferred for baking because it dissolves more uniformly than larger salts.

¢ Kosher salt also works equally well for cooking and table use. Many cooks prefer it to table for cooking because it is easier to pinch. The coarse grains adhere well to food and provide a crunchy texture.

¢ Ground or flaked sea salts dissolve very quickly and provide little texture. They work well on the table, and on foods such as popcorn, because their irregular shapes adhere well to the kernels.

¢ Sea salts and seasoned sea salts are best for table use, where their size and texture can be fully appreciated. They provide good crunch and texture. Some say the higher mineral content also produces distinct flavors.