Of all the epiphanies that emerge from reading Salt Fat Acid Heat, perhaps none are as unexpected as those in the brief but informative chapter on acids. Although I realized some years ago that Asian cuisines were particularly good ways to learn about acids in cooking, until I read this chapter I probably would have only thought of vinegar and tomatoes, lemons & limes, and maybe wine, as the usual acidic suspects found in American dishes.
But alas, there are so many more acidic flavorings with which we balance our foods. And not only that, but attention to culinary acids can make a dish extraordinary. Acids balance flavors, acting “as a foil to salt, fat, sugar, and starch” (SFAH, 103). This is why a drizzle of lime or dollop of sour cream tastes so good on a taco, and the bacon vinaigrette in a spinach salad makes the flavors pop.
As with salts and fats, Salt Fat Acid Heat teaches us that acids are unique to specific cuisines around the world and include a whole lot more than obvious ones like citrus. Samin distinguishes between “cooking acids” and “garnishing acids” in order to help us understand how acidic flavors can be layered in a dish. Cooking acids are often liquids–citrus juice, vinegars, wine and wine vinegars–that are often added to a dish at the beginning of the cooking process, and which may function to make meats and veggies more tender. Garnishing acids are more varied in their form and are added to complete a dish. In American and European cuisines, dairy items such as cheese, sour cream, and creme fraiche are frequently used garnishing acids, while in Asian cuisines fish sauce, soy sauce, and pickled vegetables add acidic balance to dishes. Yogurt is the go-to acidic condiment in India and the Middle East, and my favorite preserved lemons in northern African cuisines. As with salts and fats, it’s necessary to add culturally appropriate acids to your dishes.
But what I found most surprising about Samin’s education in acids was that there are some really surprising items in our kitchens that technically fall on the acidic side of the pH scale. In fact, some of these things initially strike me as the opposite of acids: honey and sugar, for example. Hello, these are sweet, and isn’t sweet the opposite of acid/sour? Well, it’s complicated. Think of how many times your mom screamed at you about your teeth falling out of your head if you ate too much sugar. And she was right, because sugar is acidic–that’s precisely why it can damage our teeth.
Take a look at the drawing of the pH level of things Samin tested in her home kitchen:
Sugar tested at 5.6 on the pH scale, which, granted, is pretty close to 7, which is neutral in its chemical properties (anything 7 or above is considered base or alkaline). In other words, it’s not like sugar is highly acidic. But still, it is interesting that sweet is, in this sense, not the “opposite” of acid; sweetness might just be a lesser form of acidity. Anyway, the point is that if we develop a sense of where the items we cook with fall on the pH scale, we’ll have a better understanding of how one ingredient can balance another, and our dishes will be so tasty!!!
Plus, not only do acids balance flavors, but they can also aid–or hinder–the aesthetic qualities of our foods. A squeeze of fresh lemon juice on sliced apples will prevent them from browning, and a splash of vinegar in your poached eggs’ water can help the whites to coagulate more quickly. On the other hand, acid can dull the green of veggies, so be sure to add the acid just before serving. And when cooking dried beans, you want to reduce the acidity because it will make the beans tough, so add a little baking soda to the cooking water to counter their natural acids.
One of the most interesting things I learned from this chapter of SFAH was that I’m going to have to revise my views on ketchup. For years, I’ve kind of written off ketchup as something appropriate only for the palates of 5-year-olds. I wince as I look back on how much my elementary-school aged self loved ketchup on open-faced grilled cheese (made with American cheese, of course). But Samin makes a really interesting case for ketchup as a key source of umami flavor, with its combination of sweet, salty, and acid. I’m going to have to get off my high horse and give ketchup another chance. (As of yesterday, Locavore is now carrying Spicy Ketchup made by Golden Oaks Food/Nunda Mustard and I really like it. It contains ghost pepper oil, so it is hot, even to me!)
One last thing: the acid chapter of SFAH closes with the observation that we should pay attention to the balance of acids not only in each dish, but also in our entire meal. If you’re serving a buttery entree, for example, it needs to be paired with something sharply acidic, such as a vinaigrette on a nice salad. You need an acidic flavor in a meal to balance out the salty, fat, or sweet stuff! I will be contemplating these new insights for decades to come.