The phrase “flavored oils” might conjure images of Italian-ish garlic and herb oils, chile oils to dress Sichuan dishes or maybe supermarket truffle oils. But there’s some new players on the scene that are changing the concept: deep green pine oils and dill oils, intense and dimensional rose oils, oils flavored with not-previously considered-edible things such as aromatic woods, onion ash or hay. In the kitchens of creative restaurants around the world, infused oils let cooks add a precise dose of concentrated, blendable flavor to any dish. Think of them as a customizable, flavor-capture-and-delivery technique — or maybe cocktail bitters for food.
At Ink on Melrose Avenue in Los Angeles, chef Michael Voltaggio uses several oils he makes in-house, including a black-olive olive oil — olive oil blended and infused with kalamata olives — and black garlic oil. A favorite, the burnt coconut oil currently adorning a dish of big eye tuna, was a happy accident — a forgotten sheet tray of toasting coconut burnt to a crisp in the oven had an intriguing aroma but a gritty and ashy texture. A quick trip in the blender with good olive oil transformed it into a nutty, sweet and pleasantly charred-tasting product. And when combined with coconut milk in an acidic fish-sauce dressing, the result was a layered, complex coconut flavor.
At the Catbird Seat in Nashville, chef Ryan Poli briefly loses count listing the flavored oils he produces in-house. There are seven — mushroom, pine, shrimp, chile, charred spring onion, roasted kelp and lemon verbena.
Using essential oils — produced by steam-distilling ingredients to collect their aromatic components in an extremely concentrated form — is one option. Another is DIY, which allows for a greater degree of customization and use of ingredients that are either inedible or that might otherwise end up in the compost. Poli’s pine oil allows the chef to use the flavor of fresh pine trees in his cooking. Voltaggio’s burnt coconut oil transforms a mistake into a bonus addition to his culinary arsenal.
And unlike some modern restaurant tricks, like rotovapping or centrifuging, this one is easy (and inexpensive) to pull off at home.
A little chemistry is useful here. The simple phenomenon that oil and water don’t mix — that matter prefers the company of other matter that is similar on a molecular level to itself — is what enables the flavor concentration that makes such oils so versatile. Much of flavor comes from aroma — that is, most of what you taste when you eat something is actually the result of your sense of smell — and aroma molecules tend to be nonpolar, like fat and oil, instead of polar, like water. So, flavor molecules will happily take up residence in nonpolar materials like oils and fats, a process called extraction — or sometimes infusion or tincturing.
Think of what happens when you leave butter in your fridge for too long — it picks up the aromas of other foods nearby, and rarely in a good way. As is their wont, aroma compounds in flavorful ingredients circulate in the air. When they encounter butter, their mutual chemical similarity acts like a sponge, like (butterfat) dissolves like (aroma molecules), unintentionally flavoring it.
Intentional aromatic extractions are almost as easy to produce. While you could stick a flavorful ingredient like coriander seeds next to butter and let it gradually sponge up the nonpolar flavor molecules, you can get much faster results by blitzing those coriander seeds with double their weight in oil in a blender, and letting the mixture marinate at room temperature for 24 hours. Strain through a coffee filter or triple-layered cheesecloth, and you have an oil that will keep in the refrigerator for a few weeks, a few months in the freezer.
This basic recipe is more like an improvisational tool. You can swap out coriander seeds, say, for an equal weight of hojicha tea or lemon verbena — just play with whatever flavors suit your tastes.
Speaking of taste: Bitter-, sour-, salty-, sweet- and umami-tasting molecules are polar and extract poorly into oils and fats, so coffee bean or Lapsang souchong oils have softer, less bitter and more aromatic qualities than their corresponding water extracts (i.e. coffee and tea). Capsaicin, the molecular culprit behind chile heat, on the other hand, is extremely oil soluble, as fans of Sichuan cuisine can attest.
Oils can also be used to preserve the flavors of the season well past their best-use date. When I worked at René Redzepi’s restaurant Noma in Copenhagen, we made tubs of oils flavored with blink-and-you’ll-miss-the-season Nordic pine, dill, seaweeds and flowers. Harvest-time gluts of green herbs such as dill, basil or tarragon (blanched and shocked before blending) are particularly well-suited for the process. So are flavorful scraps (shrimp shells, wild mushroom trim), as well as flowers (roses, lavender, geranium) and spices (coriander, cardamom, lime leaf, rosemary) and blends (ras el hanout or shichimi togarashi).
How to operate these new flavor-power tools? Use as you might a very peppery olive or chile oil — try drizzling them over root vegetables, on poached chicken or fish, avocado toast, even ice cream. Dribble liberally into dressings, stews, soups, cocktails. Fold into popcorn or your favorite grain bowl. Or go highbrow and dress a grilled Santa Barbara prawn with charred spring-onion-top oil. You’re a far cry from cheap white truffle oil, you sophisticated home cook.
Johnson was the resident scientist at Noma in Copenhagen and is now a researcher at the MIT Media Lab in Cambridge, Mass. She holds a PhD in flavor chemistry.