Chefs and food scientists often think about how one flavor in a dish is affected by other flavors. Being able to balance flavors is the key to creating satisfyingly seasoned dishes. Cooks in the know can use simple molecules like salt or sugar to cover unpleasant tastes or round out weak ones (you can learn some of these tricks in our dinner party fix-it quiz ).

This experiment will show you how easy it is to tone down a bitter flavor. Tonic water contains quinine, a bitter compound that adds character to cocktails. With a pinch of salt, you'll see how easy it is to take that bitter edge off. Remember, this trick will work with bitter foods, too. But don't go overboard: Too salty is almost as bad as too bitter.

1. Fill 4 glasses with some tonic water. Try to put the same amount in each glass, about 4 ounces, or 200 milliliters.

Tip
Temperature also takes the edge off bitter flavors. That's why coffee tastes better hot than cold. Heat will destroy the bitter compounds in some foods, making them taste better. Learn more in the dinner party fix-it quiz .

2. Line the glasses up and number them 1 through 4.

3. Put a pinch of salt in glass #2, half a teaspoon of salt in glass #3, and a whole teaspoon of salt in glass #4.

4. Take a sip or two of the unsalted tonic water in glass #1. Does it taste bitter to you?

5. Take sips of the other glasses of tonic water, and take note of how the bitter flavor changes as the amount of salt increases. You can write your thoughts down, and then try tasting from the glasses in reverse order. Does it taste any different to your palate?

The basic tastes of sweet, salty, sour, and bitter are sort of like a palette of complementary colors. If you add some of one, it mixes with the others and changes the overall sensation. This is true for other combinations of tastes besides bitter and salty: Some cooks use a touch of sugar to balance the flavor of salt, and it's no secret that adding sugar to lemonade makes it less sour. You can experiment with these flavor balances each time you cook, and especially when you're making easy-to-adjust recipes like salad dressings.

• Salt can also take the bitter edge off a fruit. Next time you have a grapefruit, instead of sprinkling sugar on it, try a little salt. How different does it taste?

• Tomatoes can be bitter if they're not ripe. Try sprinkling some salt on a tomato to see if that rounds out the flavor a bit. You could also try adding a bit of extra salt to a dish that calls for tomatoes if the ones you're using are a little on the green side.