There are some foods that we think of as just naturally going together: cookies and milk, soup and sandwich, apples and cheese. The reasons for those pairings are as complex as the flavors themselves. Part of it just comes down to cultural preferences: should French fries be paired with ketchup, mayonnaise or gravy? The answer depends on what you grew up with. But flavor is ultimately about chemistry, and offers many variables to experiment with. When one food has a strong flavor, it diminishes your ability to taste that flavor as well in the food that it’s paired with. A piece of cake, for example, helps to moderate the sweetness of your dessert wine. Salt can help to reduce bitterness, which is why pretzels go so well with a mug of beer. At other times, one flavor can enhance another—vanilla is such an effective flavor enhancer that even chocolate doesn’t taste quite right without it. And food cultures all over the world favor the pairing of fats with astringent flavors (sharp, tangy, sour, etc.), whether that’s a dill pickle with your deli sandwich, wine with a fancy cheese assortment, or the zing of sliced ginger with your sushi.