Unless otherwise specified I use a fine-grained sea salt called Lima Atlantic Sea Salt in my recipes. There are significant differences between the various kinds of salt in terms of flavor, density, texture, purity, nutritional profile, intended uses, and cost. Here is how I approach the choice of salt:
I avoid table salt altogether, which contains chemicals used as anti-caking agents that alter the flavor of the salt. Kosher salt is better as it’s typically pure sodium chloride free of anti-caking agents. In case you're wondering, there is nothing inherently kosher about the salt itself, but its flaky texture makes it suitable for koshering meat. I use kosher salt to season pieces of meat, poultry and seafood, because that consistency makes it so easy to apply evenly. I also use it in water to boil pasta or beans or to blanch and ice vegetables. Most of this salted water is destined for the drain anyway and kosher salt is cheaper than sea salt.
I use sea salt for everything else. Due to the absence of chemicals, pure sea salt has a cleaner, sweeter flavor than table salt. Sea salt also contains naturally occurring and desirable minerals that are absent from the chemically pure kosher salt. Sea salt comes in a variety of consistencies suited to different uses. Fine sea salt is my go to salt for most uses including salad dressings, soups, stews and sautéing vegetables. It dissolves fast and it’s easy to get a feel for the quantity used in your hands and fingers.
Fleur de Sel and Maldon Sea Salt are finishing salts with salt crystals that are just the right size to sprinkle on ready to eat foods - large enough to not completely dissolve immediately on impact with anything moist but not so large that a single crystal would ruin your bite. They make the flavors pop in your mouth and provide a little crunch – perfect as a finishing touch for a tomato salad, a piece of meat or fish or a poached egg. They are expensive, but they will last you a while if used only for their intended purpose.
I don’t have much use for coarse sea salt, which needs to go through the additional step of being ground up in a salt mill. I prefer to use salt with my hands and fingers out of an open container, so I can have a better sense of the quantities involved – something that’s harder to do with a salt mill.
Different salts can have dramatically different densities depending on the type and even the brand. A teaspoon of table salt for example will result in a much saltier taste than a teaspoon of Diamond Kosher Salt. Other recipes will assume other salts and it’s always a good idea to salt gradually to taste if possible. Over time you will develop a feel for your salt. Through experience I know what the right amount of salt for one egg feels like between my fingers. When I make a frittata with 5 eggs, I use 5 such pinches of salt and then salt the other frittata ingredients separately to taste. That way I usually get it right without having to think about tasting raw eggs.