A survey of the last twenty internet recipes I bookmarked to cook later yields 12 mentions of unsalted butter and only 2 of "butter." There are 9 mentions of kosher salt and 1 of "coarse salt" vs. 7 of "fine sea salt" and 3 just of "salt"-- about even in terms of coarse vs. fine. (Recipes from The New York Times, The Tipsy Baker, Smitten Kitchen, Food & Wine, Ruth Reichl, Andrew Zimmern, Orangette, and TheFauxMartha.) One thing is clear, however: most people now feel that they have to specify what kind of salt they're talking about. Waaay back in 2012, everybody's home cooking guru Deb Perelman wrote in The Smitten Kitchen Cookbook: "You might notice that I call for table salt in most recipes, which might seem odd in an age where salt varieties can take up several grocery store shelves. I did this for consistency. Different types, and even brands, of salt have different weights and thus saltiness that they impart to a recipe... I do call for kosher and sea salts in recipes where I feel the texture of the salt improves the final taste." Well, fast forward a few years, and Smitten Kitchen's online recipes have begun to conform more to fashion: out of 12 recipes I recently bookmarked, 4 call for either kosher or coarse salt, 7 call for fine sea salt (sometimes adding "or table salt"), and only one simply called for table salt. Oh, Deb! We count on you to be down-to-earth!
What does this mean? Why are regular butter and salt suddenly mean and unacceptable, lacking in grace and precision? What has occurred, not only between my grandmother's church cookbook and Bon Appetit, but between 2012 and today? I became very curious about where such recipe trends come from, and how they catch on.
Unfortunately, trends rarely come with a big dose of self-awareness and reflection, so when I tried to research the recent rise in popularity of unsalted butter, what I mostly saw was people talking about how unsalted butter has always been preferable for controlling salt content in dishes, and better because (and I have never heard this discussed before) salt is a preservative, and therefore unsalted butter is fresher. Ohhkay. We have always been at war with Eastasia. The Kitchn does acknowledge that tastes have changed, and offers a reader poll asking which type of butter folks keep on hand (count me in the "both" column; but "unsalted" wins for these probably fairly food-sophisticated readers). Notably, butter consumption overall hit a 40-year high in 2014, and googling "unsalted butter trendy" will lead you to much discussion of the paleo craze for butter coffee. Which, if you ask me, is gross. I would totally try it if I were in Tibet, though. This story on butter consumption from Associated Milk Producers Inc. does vaguely reference the fact that "though salted butter is the clear preference of consumers, AMPI sales of unsalted quarters have been steadily growing." They would know. But I cannot find hard statistics about salted vs. unsalted butter sales anywhere.
On the other hand, Epicurious declared salted butter to be "back" in 2010. I am tragically under-hip.
Now, on to salt. Serious Eats did a great basic article on salt use in recipes in 2013. Key points: "chemically there is virtually no difference between table salt, kosher salt, and fancy sea salt.[...] Dissolve those salts in water side by side, and the differences between them become nearly indistinguishable, just as they are when you use them to season your food." Yeeessss. However, when NOT dissolved, texture can matter. The biggest reason cited here (and elsewhere as well) for using kosher (=coarse) salt preferentially is that it is easier to sprinkle by hand-- easier to pick up with your fingers, and easier to apply evenly. As for flaky sea salts, the following:
Chefs like using them because they add crunchy texture and a burst of salinity that adds interest to plated foods. It should be used exclusively for finishing dishes. Scattering on the tops of glazed loaves of bread before baking. Sprinkling over sliced perfectly cooked steak just before serving. Adding a touch of crunch to slivers of raw scallops. You get the picture. Fancy-pants food.
If you're using your fancy sea salt to cook with, on the other hand, you may as well replace your toilet paper with dollar bills, because you are flushing all of its good features down the toilet.
My guess is that there is a kind of circular action here. The more recipes call for kosher salt (perhaps for initially valid reasons), and the more people start keeping little pots of kosher salt sitting around their kitchens to sprinkle by hand, the handier it becomes to use kosher salt in your next recipe-- you already bought some! It's sitting right there! And if you end up publishing that recipe, "kosher salt" becomes the instruction, whether logically necessary or not. (Measurements do not translate 1:1 for kosher vs. table salt, so you can't simply convert all written instructions back to the nonspecific "salt.")
But Junkfood Science, even way back in 2006, said: "...over recent decades, Americans are increasingly shunning ordinary table salt; and commercial restaurants, food processors and chefs have abandoned iodized salt in response to consumer concerns it could affect the taste of foods; preferring “natural” sea salts, kosher salts and noniodized salts. Last month, Food Technology reported that this fad, along with attempts to reduce salt intakes, may be the most significant factor leading us to deficiencies again. The National Health and Nutrition Examination Surveys found that from the 1971-1974 to 2001-2002 examinations, iodine excretion in adults dropped from 320 mcg/L to 168 mcg/L — by nearly half — and the frequency of iodine deficiencies in pregnant women jumped from 1% to 7%."
Another culprit-- probably a more important one-- besides our use of fancy gourmet salts is the prevalence of processed food; The Salt Institute (admittedly, an industry trade association) also says "Salt used in processed foods is not iodized. Given that people are cooking less at home and buying either restaurant or processed foods, iodine intakes in the U.S. have declined from about 250 μg/day to 157 micrograms/day." Sorry, what? Processed foods don't use iodized salt either? Sign me up for regular use of the everyday carton of boring salt, please. I'll keep my kosher salt, Maldon sea salt flakes, and coarse Mediterranean sea salt for special occasions and, yes, Bon Appetit recipes.