Restaurants and commercially-processed ready-to-eat foods tend to contain significantly more salt, sugar, and fat than most home cooking, even that prepared according to published cookbooks. A french restaurant’s coq au vin will be saltier than what comes out of your kitchen even if you prepare it according to Julia Child (or Louis de Gouy). That actually gave me an idea. Both Child and de Gouy were Paris-trained, both wrote cookbooks, and both books are in front of me now. Assuming no significant differences arise just from the fact that de Gouy’s The Gold Cook Book came out in 1947 and Child’s Mastering the Art of French Cooking came out in 1961, the big difference, if any, should lie in the fact that Child tested her recipes at home and wrote her book to educate the mass of American home cooks, and de Gouy was a consummate industry professional whose book, while personable and even often funny, is definitely not aimed at amateurs.
I started by looking at sauces, figuring that would be the area where there was the least room for individual variation. Except for the wiggle room provided by the most frequent instructions for salt, i.e., “to taste,” which doesn’t tell us much, and “pinch,” which is also vague (you can pinch salt between thumb and forefinger, or between thumb and two, three or four fingers), the only difference I found was for bearnaise, in which Julia puts a pinch and Louis instructs us to use none at all. So that was frustrating. Louis de Gouy does use a lot more butter. Usually sweet though, so no effect on salt.
Then I just started looking for recipes they had in common. Here are some (I accounted as well as I could for quantity differences in the final product):
Onion Soup. Julia: 1 tsp Louis: to taste
Sauteed Chicken Breasts w/Brown Sauce. Julia: 1/4 tsp. Louis: “very little.”
Carottes Vichy. Julia: “Salt and Pepper”. Louis: “a few grains salt.”
And here I decided two things. First, I use much less salt than I get in restaurants, and I use a lot more salt than either Julia or Louis, going by their books. Second, restaurants don’t get the luxury of vague measurements or a line cook’s palate. Their food has to be punchy, something that doesn’t taste like the leftovers in your refrigerator, and consistent. So, salt, fat, sugar, as much as a recipe will hold, and the same every time. It’s also undeniable that some professional cooks just do not like it when people re-season their efforts. I don’t know how much that plays into it, but the impetus is to add, not subtract. At the low end, salt fat and sugar are cheap ways to get cheap ingredients to taste like something.
So you have some people who eat out a lot and at both the high and the low end there’s lots of salt, and that drags the middle along. And you have people who can’t afford to eat out much but eat lots of salty processed foods. And then you have the people who like to cook, and do a lot of it, and follow recipes, and wonder why everybody thinks it’s undersalted.