In Bitter: A Taste of the World’s Most Dangerous Flavor, with Recipes (Ten Speed, Oct.), James Beard Award–winning cookbook author Jennifer McLagan (Fat, Bones, Odd Bits), wants cooks to reconsider bitterness as a taste that not only challenges palates and culinary sensibilities, but also adds depth and balance to dishes. PW spoke with McLagan about the subjective ways we experience bitterness and some of her favorite ways to incorporate bitter elements into dishes.

Why is experiencing the taste of bitterness, as you describe it, “a whole body experience?”

Bitter is the most interesting taste. We can all agree on what is salty or sweet, and most of us agree on what is sour, but we are never ever going to agree on what is bitter, since it is a range more than an exact taste—from subtle celery leaves right through something like bitter melon. Receptors for bitter are throughout your whole body, not just on your tongue. They are all over the place because they’re designed to signal something as possibly dangerous or toxic, so it is a very important taste. These receptors also can signal something that is good for you, since bitter signals many phytochemical compounds. A small amount of toxin can be pleasurable, like caffeine, so it’s a very fine line. There’s a current body of research exploring the benefits of bitter.

What is the science behind the human instinct to both avoid and crave bitter flavors?

We have so many more bitter receptors than we do for other tastes since bitter can signal toxicity. There’s a universal response—people grimace, screw up their face, and want to spit out what’s on their tongue, and it’s more pronounced in babies and young children because they have more taste buds. As we age, we don’t have as many taste buds, and we can get used to bitter flavors. As we experience more bitter flavors, we are more likely to crave and appreciate the digestive powers of bitter, which can, for example, balance fatty foods.

You identify bitter as both a “taste” (along with salt, sweet, and sour) and a “flavor.” Why can it be both?

I understand that scientists are more precise than I am saying that taste is what’s on your taste buds, and flavor is determined more by your brain. Foodies use the terms interchangeably. I do agree that flavor is based on a whole range of sensations and all our senses. We can discern fat, metallic, and soapy tastes, too, though I find that making the distinction between taste and flavor is not particular useful, unless you are a scientist.

Would you say you’re on a mission to broaden our palates and overcome our bias against bitter foods?

I’ve been on a mission ever since I started writing cookbooks! I’ve always championed unloved foods that really should be loved and all things that are important in the kitchen to the taste and flavor of food. I haven’t written a book full of bitter recipes. What I want to show is that by trying to add a little bit of bitterness into what you cook, you will add balance and complexity. Your cooking will benefit from a little bit of bitterness. For example, when cooking caramel just to the right point, it is so much more complex than a caramel without that degree of bitterness. Or if you make truffles, don’t dip them in melted chocolate or roll them in powdered sugar. Roll them in cocoa. The first bite will be bitter but enhance the contrasting sweetness that follows.

What do you think bitterness adds to dishes?

It gets your taste buds working and is more satisfying in many ways. All those packaged salad mixes are now adding radicchio. Its red color may help us think it is sweeter than it is, but it adds a complexity, depth, and an interest. It finishes off the flavor. When using bitter in cooking, you need to create a mixture, since a dish can’t be all sweet or salty, so add it to the dish or on the plate itself. With a fatty duck dish, it’s so much better with a side of rapini or bitter greens. A squeeze of lemon juice keeps a dish from being flat, or a tablespoon of coffee in a pan sauce rounds it out. You won’t taste any bitterness or coffee flavor. You need some bitterness in a menu or plate to balance out a whole meal.

Historically speaking, how have people’s preferences for bitter foods changed over time?

I think that since sugar became cheaper, we’ve moved away from bitterness. We tend to go toward the sweetness, though this may be a cultural preference. Brits have a much greater love for a pint of bitter ale than Americans do. I believe you appreciate bitter best if you grew up with it.

To what extent does our understanding of bitterness need a makeover?

We need to stop thinking of it as something negative, and start thinking of it as a positive addition to the palate of flavors and taste. Bitter needs to get a positive image, and you need to expand your horizon of what you think of as bitter. Start by tossing some celery leaves or bitter greens into the Boston lettuce in your salads. Another way is to go the supermarket and get some quality chocolates—65%, 75%, or 85% cocoa. Let a piece melt on your tongue, and over time you will begin to appreciate it. It’s a great way to begin tasting more than the sweetness and to start experiencing the raisiny fruitiness of chocolate that emerges once you remove some of the sugar hiding the rest of the flavor.

How difficult was it to select foods to include in this book?

I thought I knew exactly what I was going to include, and I discovered that what I thought of as bitter was not necessarily included in other people’s lists. Some foods were obvious, and then there were things that I thought were bitter but aren’t really anymore, like eggplant. I had a huge list and had to narrow it down, and I probably left things out. I’m sure in the future I’ll continue to discover other bitter things.

Which recipes in your cookbook are good examples of how bitterness enhances deliciousness?

I love them all! I just made the chicken liver recipe the other day. The liver has a touch of bitterness, but with the sweetness of the caramelized onions, the saltiness from the capers, the herbal-ness of rosemary, and the glaze from the Fernet-Branca, the bitterness is balanced. Another good example is caramelized oranges, because you take caramel to the point with that little bit of bitterness, and the orange peel and small bit of pith make the dish much more interesting to eat.

Your previous books are primarily meat-focused, while Bitter examines a single taste experience. Are there other single topics that you plan to explore in the future?

I don’t know. I think I like the single-subject cookbook because exploring one topic takes you into interesting places, but it’s a lot of work. I enjoyed my summer off. [But I’m interested in] lots of things people have just forgotten about. For example, there’s a resurgence of foraging, which has been around for a long time. As for my earlier focus on meat, well—I eat vegetables, too! It’s hard in the food world to always come up with something new, but I have a couple of ideas.

How would you describe your own journey with bitterness? Are there any ingredients that you have grown to love or any that you still can’t quite enjoy?

I always had a tendency toward liking things that were bitter. I wouldn’t have started on a book if I didn’t. I like to cook with Fernet-Branca, and I love gin and tonic, but I now prefer only homemade tonic water and could never open a can of Schweppes. I find I need sweet things less and less as time goes by. I’m much happier to end my meals with something bitter, especially something in a glass, like a bitter tipple. And cardoons are marvelous vegetables, though probably no one has ever seen cardoons except on a restaurant menu. Maybe I can start a cardoon craze.

Bitter: A Taste of the World's Most Dangerous Flavor, with Recipes by Jennifer McLagan. Ten Speed, Sept. ISBN 978-1-60774-516-7