Salt, Fat, Acid, Heat. Samin Nosrat
acidic, in a way I never imagined a fat could be.
The following autumn I was in Liguria, a coastal province, during the raccolta. Olio nuovo pressed on the shores of the Mediterranean was wholly different: this oil was buttery, low in acid, and so rich I wanted to swallow spoonfuls of it. I learned that where olive oil comes from has a huge effect on how it tastes—oil from hot, dry hilly areas is spicy, while oil from coastal climates with milder weather is correspondingly milder in flavour. After tasting the oils I could see how a peppery oil would overwhelm a delicate preparation such as fish tartare, while the more subtle flavour of a coastal oil might not be able to stand up to the bold flavours of a Tuscan bistecca served with bitter greens.
At Zibibbo, Benedetta Vitali’s Florentine trattoria, we used peppery Tuscan extra-virgin olive oil more liberally than any other ingredient. We used it to make salad dressings. We used it to drench the dough for the focaccia we baked each morning. We used it to brown soffritto, the aromatic base of onions, carrots, and celery at the foundation of all of our long-cooked foods. We used it to deep-fry everything from squid to squash blossoms to bomboloni, the cream-filled doughnuts I ate with gusto every Saturday morning. Tuscan olive oil defined the flavour of our cooking; our food tasted delicious because our olive oil was delicious.
As I travelled throughout Italy, I saw how fat determines the particular flavours of regional cooking. In the North, where pastures and the dairy cattle they sustain are abundant, cooks use butter, cream, and rich cheeses readily in dishes such as polenta, tagliatelle Bolognese, and risotto. In the South and on the coasts, where olive trees flourish, olive oil is used in everything from seafood dishes to pastas and even desserts such as olive oil gelato. Because pigs can be raised in just about any climate, though, one thing unites the diverse regional Italian cuisines: pork fat.
As I immersed myself in the culture and cuisine of Italy, one thing became clear: Italians’ remarkable relationship to fat is essential to why their food tastes so good. Fat, then, I realised, is the second element of good cooking.
WHAT IS FAT?
The best way to appreciate the value of fat in the kitchen is to try to imagine cooking without it. What would vinaigrette be without olive oil, sausage without pork fat, a baked potato without sour cream, a croissant without butter? Pointless, that’s what. Without the flavours and textures that fat makes possible, food would be immeasurably less pleasurable to eat. In other words, fat is essential for achieving the full spectrum of flavours and textures of good cooking.
Besides being one of the four basic elements of good cooking, fat is also one of the four elemental building blocks of all foods, along with water, protein, and carbohydrates. While it’s commonly believed that fat, much like salt, is universally unhealthy, both elements are essential to human survival. Fat serves as a crucial backup energy source, a way to store energy for future use, and plays a role in nutrient absorption and essential metabolic functions, such as brain growth. Unless you’ve been directed by your doctor to strictly reduce your fat consumption, you don’t need to worry—there’s nothing unhealthy about cooking with moderate amounts of fat (especially if you favour healthy plant- and fish-based fats). As with salt, my aim isn’t so much to get you to use more fat as it is to teach you how to make better use of it in your cooking.
In contrast to salt, fat takes on many forms and is derived from many sources (see Sources of Fat, here). While salt is a mineral, used primarily to enhance flavour, fat plays three distinct roles in the kitchen: as a main ingredient, as a cooking medium, and, like salt, as seasoning. The same type of fat can play different roles in your cooking, depending on how it is used. The first step in choosing a fat to use is to identify the primary role it will play in a dish.
Used as a main ingredient, fat will significantly affect a dish. Often, it’s a source both of rich flavour and of a particular desired texture. For example, fat ground into a burger will render as it cooks, basting the meat from within and contributing to juciness. Butter inhibits the proteins in flour from developing, yielding tender and flaky textures in a pastry. Olive oil contributes both a light, grassy flavour and a rich texture to pesto. The amount of cream and egg yolks in an ice cream determines just how smooth and decadent it’ll be (hint: the more cream and eggs, the creamier the result).
The role fat plays as a cooking medium is perhaps its most impressive and unique. Cooking fats can be heated to extreme temperatures, allowing the surface temperature of foods cooked in them to climb to astonishing heights as well. In the process, these foods become golden brown and develop the crisp crusts that so please our palates. Any fat you heat to cook food can be described as a medium, whether it’s the peanut oil in which you fry chicken, the butter you use to sauté spring vegetables, or the olive oil in which you poach tuna.
Certain fats can also be used as seasoning to adjust flavour or enrich the texture of a dish just before serving: a few drops of toasted sesame oil will deepen the flavours in a bowl of rice, a dollop of sour cream will offer silky richness to a cup of soup, a little mayonnaise spread on a BLT will increase its succulence, and a smear of cultured butter on a piece of crusty bread will add untold richness.
To determine which role fat is playing in a dish, ask yourself these questions:
• Will this fat bind various ingredients together? If so, this is a main ingredient.
• Does this fat play a textural role? For flaky, creamy, and light textures, fat plays the role of main ingredient, while for crisp textures, it’s a cooking medium. For tender textures, fat can play either role.
• Will this fat be heated and used to cook the food? If so, this is a cooking medium.
• Does this fat play a flavour role? If it’s added at the outset, it’s a main ingredient. If it’s used to adjust flavour or texture at the end of cooking the dish as a garnish, it’s a seasoning.
Once you’ve identified which role fat will play in a dish, you’ll be better equipped to choose which fat to use, and how to cook food that will result in the taste and texture you’re after.
FAT AND FLAVOUR
Fat’s Effect on Flavour
Put simply, fat carries flavour. While certain fats have their own distinct flavours, any fat can convey aromas—and enhance flavours—to our palates that would otherwise go unnoticed. Fat coats the tongue, allowing various aromatic compounds to stay in contact with our taste buds for longer periods of time, intensifying and prolonging our experience of various flavours. Peel and slice two cloves of garlic. Gently sizzle one clove in a couple of tablespoons of water, and the other in the same amount of olive oil. Taste a few drops of each liquid. You’ll have a much more powerful impression of the garlic flavour in oil. Take advantage of this capability to intensify and circulate flavour by adding aromatics directly into the cooking fat. When baking, add vanilla extract and other flavourings directly into the butter or egg yolks for the same result.
Fat enhances flavour in another extraordinary way. Because cooking fats can withstand temperatures well beyond the boiling point of water (100°C at sea level), they perform a crucial task that water cannot—the facilitation of surface browning, which typically does not begin at temperatures below 110°C. In some foods, browning will introduce entirely new flavours, including nuttiness, sweetness, meatiness, earthiness, and savouriness (umami). Imagine the difference in flavour between a poached chicken breast and one browned