Spice Science: A Toast to Toasting

We toast many of the spices that go into our blends ourselves, at our warehouse in North Carolina. Some get a light toast and some are roasted deep and dark, and it makes a big difference in how a blend tastes. Here's what happens when a spice meets heat, how to do it in your own kitchen, and the blends where we've done the toasting for you.

What happens in the pan

Most of a spice's flavor comes from aromatic oils held inside the seed, bark, or pod. When you heat whole spices in a dry pan, the moisture in them cooks off and some of those oils rise into the air. That's why you smell cumin in the kitchen before the seeds look any different.

A second change happens on the surface. Spices contain small amounts of sugar and protein, and under heat they react with each other to form new flavor compounds that weren't in the raw seed. This is the Maillard reaction, the same chemistry that browns bread in the toaster and gives roasted coffee and seared steak their flavor. The new compounds taste nutty, roasty, and a little bittersweet.

Toasting also changes the flavors that were there to begin with. Cumin loses some of its sharp, bitter edge and becomes earthier and rounder. Coriander turns warm and nutty. The seeds dry out and become brittle, so they break down easily in a mortar or spice grinder.

How to toast at home

Start with a heavy skillet, cast iron if you have one, big enough to hold your spices in a single layer. Warm it over medium heat for a few minutes with no oil, then add your whole spices and keep them moving with a spoon or a shake of the pan. Within 30 seconds to a minute you'll smell them. Pale seeds like coriander and fennel darken a shade, while darker ones like cumin may barely change color, so trust your nose over your eyes. Mustard and sesame seeds pop and hop around the pan when they're close.

As soon as they're fragrant and a shade darker, tip them out onto a plate to cool. Spices keep cooking in a hot skillet, and there's no rescuing a burnt one. If you see smoke, pull them off the heat right away.

A few more things we've learned along the way:

• Toast spices of a similar size together, so they finish at the same time.
• Go gently with dried chiles and open a window. Chile smoke stings your eyes and throat.
• Toast whole spices only. Ground spices scorch in seconds in a dry pan. For those, warm them in a little oil or butter for 30 seconds before the rest of your ingredients go in.

Good spices to start with are Cumin Seed, Indian Coriander Seed, Fennel Seed, Brown Mustard Seed, Black Sesame Seed, and Tellicherry Black Peppercorn. Grind them into a powder, drop them whole into a simmering pot, or scatter them over a finished dish.

Here's our full guide on toasting at home: How to Toast Spices.

The blends we toast for you

We toast each blend to its own level, from a light roast to a deep, dark one. Here they are from darkest to lightest.

Sri Lankan Curry is our most heavily toasted blend. We dry roast the spices dark and leave out turmeric, so the powder comes out deep brown instead of yellow. You taste coriander, cumin, cinnamon, and fennel, with a little heat from Japones chiles. Use it in hearty meat curries, or toss it with squash and root vegetables before roasting.

Kashmiri Garam Masala is roasted dark too, with cardamom, cinnamon, nutmeg, and mace. Stir a spoonful into dal or a pot of chickpeas near the end of cooking, or add it to berry compote with a touch of vanilla.

Roast Chai is our mellow chai. We roast coriander, cinnamon, fennel, cumin, black pepper, and clove, and leave out the ginger and cardamom. Simmer it, then add a black tea like Jorhat Assam, and you'll taste notes of chocolate and coffee in the cup. Rooibos makes a caffeine-free version.

Syrian Za'atar is built on toasted cumin and coriander, with toasted sesame, tart sumac, and a hint of anise. Sprinkle it on lamb before and after grilling, on eggs, or over flatbread brushed with olive oil.

Seattle Salmon Rub is lightly roasted. You taste orange peel and brown sugar first, with star anise, cumin, and fennel underneath. Rub it on salmon before it goes on the grill or into the oven, or try it with sweet potatoes.

Here's a toast to the Maillard reaction, and to whatever you cook with it this week.

 - World Spice