Blooming Spices: Why Aromatics Go into Fat First

Aroma dissolves in fat, not water

Most of what you smell in a spice — terpenes, capsaicin, curcumin — is fat-soluble. Stirred into water only some of it comes out; hit with hot oil, far more is extracted and it spreads through the whole dish.

That is why Indian, Thai and Middle Eastern cooking almost always starts by frying spice in fat. Butter Chicken, Biryani and Chana Masala all do.

Whole spices first, ground spices later

• Whole (cumin seed, cardamom, cinnamon, cloves, bay): into the hot oil first. Twenty to thirty seconds and the aroma bursts out.
• Ground (chilli powder, turmeric, ground coriander, garam masala): burns far more easily. These go in later, just before the liquid.

Ground spice can survive in the pan for roughly thirty seconds. After that it turns bitter. If you are unsure, add a splash of liquid first to bring the temperature down.

The order exists for a reason

1. Heat the fat. 2. Whole spices — move their aroma into the fat. 3. Onion — the slowest. Drive off water, develop sweetness. 4. Garlic and ginger — they burn much faster than onion. In once the onion is half done. 5. Ground spices — thirty seconds. 6. Tomato paste or liquid — drops the temperature and lifts the fond.

Add garlic with the onion and it burns before the onion is cooked. Getting just this order right changes a curry noticeably.

Tomato paste is something you fry, too

Stirred straight into liquid, tomato paste keeps a sharp raw acidity. Fried in fat for a minute or two, until it darkens and starts to stick, it turns sweet and savoury. It is why the sauces in Pique Macho and Iraqi Dolma look as deep as they do.

Garlic is three different ingredients depending on heat

• Low heat, aroma only: sweet and mild. This is what Aglio e Olio is aiming at — browning it is a failure.
• Medium, browned: nutty and much deeper.
• Burnt: bitter, and irreversible.

Same clove, three outcomes. See Heat control.

Aromas that go in at the end

Anything heat-fragile is added off the heat.

• Fresh herbs (coriander, basil, parsley, dill): long cooking drives the aroma off.
• Toasted sesame oil: a finishing oil, not a cooking one.
• Garam masala: often added a second time at the end, even in India.
• Black pepper: ground fresh. Pre-ground pepper has almost no aroma left.

Storage

Ground spices lose most of their aroma in six to twelve months; whole ones keep two or three years. Grinding as you need it makes more difference than buying new spice — buy whole and grind. It matters most where the aroma is the dish, like the Sichuan pepper in Mapo Tofu.