February 7, 2011

Keys To Food Flavours

Harold McGee’s Keys to Good Cooking (2010 Doubleday) provides simple statements of fact and advice, along with brief explanations that help cooks understand why, and apply that understanding to other situations. Not a cookbook, Keys to Good Cooking is, simply put, a book about how to cook well.

Flavours are the major source of our pleasure in eating. They come from specific chemicals in foods, usually present in tiny amounts, which we are able to sense with our taste and smell receptors. Good cooks hone their ability to analyze food flavours, recognize how they can be improved, and make adjustments.

1. Flavour is a combination of taste and smell. We sense taste on the tongue, and smell, or aroma, in the nose.

2. There are five basic tastes:

  • Saltiness comes mainly from sodium chloride, in foods and added in the form of salt crystals.
  • Sourness comes from acids of several kinds, especially citric and malic acids in fruits, acetic acid in vinegar, and lactic acid in fermented foods such as yogurt and cheese, cured sausages, and sauerkraut. Acids stimulate saliva flow and contribute to the mouthwatering quality of foods and drinks.
  • Sweetness comes mainly from various kinds of sugars found in plants and in milk. There are many different chemical sugars, all with names ending in -ose. Table-sugar sucrose is sweeter than corn-syrup glucose and milk-sugar lactose, but less sweet than honey’s main sugar, fructose.
  • Savoriness, also called by the Japanese term umami, is the brothy, round, mouthfilling taste caused by monosodium glutamate (MSG) and a few other chemicals. It’s strong in meat stocks, soy sauce, aged cheeses, mushrooms, and tomatoes.
  • Bitterness is the characteristic taste of chemicals that some plants make to deter animals from eating them. This is why it takes getting used to, and why not all people enjoy it. Bitterness is strong in chicories, brussel sprouts, and mustard greens, and an important part of coffee, tea, chocolate, and beer flavours. Added salt greatly diminishes bitterness.

3. Pungency and astringency are other important mouth sensations. Pungency is the heat and bite of black and chili peppers, ginger, raw garlic and onion, and mustard, wasabi, watercress, and arugula. Astringency is the drying, rough effect caused by tannins in strong black tea or red wine.

4. There are hundreds of different aromas in foods. Aromas are what individualize foods and give them their specific flavour identities. All fruits have sweet and sour tastes, but only apples smell like apples, peaches like peaches.

5. There are many different aroma qualities in foods, which may smell not just fruity, meaty, fishy, eggy, nutty, or spicy, but also flowery, grassy, earthy, woody, smoky, leathery, and barnyard-y.

6. Food aromas are always mixtures of aroma chemicals. Like chords in music, food aromas are an integrated combination of several individual chemical notes. Coriander seed and ginger share a lemony note in their spiciness; ripe banana has a note of clove.

7. When we combine ingredients in cooking, we create new aroma mixtures. Herbs and spices give us dozens of notes to fill out the flavour harmony of a dish.

8. Heat changes food flavours. Cooking gives meats and fish stronger flavours than they had when raw. It makes onions and garlic milder, cabbage stronger. Mustard greens lose their pungency and gain bitterness.

9. Cooking can add new flavours to foods. Frying in oil or fat creates a characteristic flavour from changes in the fat molecules.

10. High heat or prolonged heat creates especially delicious “browned” flavours. When a food turns brown in the frying pan or oven, or on the grill, it’s a sign that heat has caused flavourless proteins and carbohydrates to react together to form hundreds of taste and aroma molecules. The browning reactions are most productive at temperatures above the boiling point of water, so foods brown best when heat dries out their surfaces.

Reprinted with permission from Harold McGee’s Keys to Good Cooking (2010 Doubleday).