Down & Dirty: Citrus

Every week we get Down & Dirty, in which Nozlee Samadzadeh breaks down our favorite seasonal fruits, vegetables, and more by the numbers.

Citrus are winter's glory, the bright spot of sunshine amongst a cellar's worth of dirt-covered root vegetables. There's a fantastically wide array of them, too -- so many that we're taking two weeks to cover them all. Stay tuned for tiny citrus next Friday, because today it's all about the big guns: orange clones, grapefruit's meaty predecessor, hard-to-find Bergamot, and everything in between. (Bonus points if you correctly identify all 8 varieties in the above photo. No peeking!)

1(a). Navel Orange: These are the quintessential orange, what we envision when we think of the fruit: convenient, sweet, juicy, and dependable. Why so dependable? Well, it helps that all navel oranges are clones! That's right -- because they're seedless and propagated by grafting, navel oranges are all direct descendents of the same tree. Of course, there are variations based on other factors: oranges grown in humid, southern regions like Texas have thinner skin and are lighter in color, while cooler climates like California produce thicker-skinned, more brightly colored fruit.

1(b). Bellybuttons: The "navel" of a navel orange does indeed look like one, but what is it really? A more accurate name for the fruit would be "conjoined twin oranges" -- that bellybutton is another orange, grown from a mutation that causes a second fruit to start growing at its opposite end! This is the genetic change that caused the fruit to become seedless, so next time you're snacking on a navel orange, give thanks to those tiny segments.

2. Blood Orange: Everything looks normal...until you peel them, that is. Blood oranges' color, much like red cabbages and red grapes, comes from the presence of anthocyanins in the fruit's flesh. The color develops with the onset of cooler temperatures at night, which means only a few climates are ideal for growing blood oranges -- Italy and California produce the best ones -- and according to Harold McGee, their color starts out at the blossom end of the fruit and radiates outward. (This is why you may have purchased a blood orange to discover orange or streakily orange-red flesh.) That gorgeous color affects the fruit's flavor: blood oranges have a deeper, sweeter flavor with raspberry-like undertones.

Based on their unusual colors, it's easy to think that blood oranges and pinkish Cara Cara oranges are related. In fact, Cara Caras' color comes from lycopene -- the same red pigment that colors grapefruit, tomatoes, and watermelons!

3. Minneola Tangelo: As you may have guessed from their name, Minneolas are a hybrid variety of citrus -- a cross between a tangerine and a pomelo, in fact, developed in Florida in the 1930s. You'll know them right away from the knob on their blossom end and their intensely red-orange skin. Inside, Minneolas are thin-skinned, extremely sweet and juicy, and not too acidic, making them the perfect snacking citrus.

4(a). Clementine: Clementines are part of the larger family of mandarin oranges originating in Japan, although Clementines were originally hybridized somewhere in the Mediterranean. They're by far the most popular variety of mandarin for their low acidity, their thin skin and membranes, and -- it must be said -- their sheer snackability. (Raise your hand if you've ever accidentally eaten a half dozen clementines before catching yourself.) Satsumas, a Japanese mandarin, are like more delicate clementines -- keep an eye out for them during their winter season.

4(b). Thin Skin: Sometimes being thin-skinned is a good thing. Clementines are a perfect candidate for marmalade because their skin has so little pith, although you will have to add high-pectin seeds (like lemon or quince) to make it gel. Nigella Lawson even puts whole, boiled clementines -- skin, pith, and all -- into a flourless cake. And mild-flavored clementine orangettes would make the perfect homemade gift.

5. Tangerine: Like clementines, tangerines are a variety of mandarin orange. They're squat, heavy for their size, and have thin skin that dries out easily. (This is why grocery-store tangerines often have brownish striations.) Tangerines are seedy little buggers -- one little fruit can have as many as 24 seeds! Their intensely sweet, syrupy juice is worth it, though, whether you're eating them out of hand or caramelizing their juices for a vinaigrette.

6. Grapefruit: You'd never guess it, but it makes perfect sense: grapefruit is a hardy, weather-resistent hybrid between bitter-skinned pomelo and the sweet orange. Depending on the orange cross, grapefruit flesh can be yellow, light orange, intensely pink, or red (in the case of the popular Ruby Red hybrid), but no matter what it has a bitter sweetness that's more similar to Campari than Tropicana. Because of their bitterness, grapefruits aren't eaten in segments like other oranges -- you're better off broiling halves before diving in with a grapefruit spoon, juicing them, or adding their zest to a minty pound cake.

7. Pomelo: You can't tell just by the photo, but pomelos are huge -- easily 6-8 inches in diameter. Native to South Asia, they're one of the few widely available citrus fruits that aren't a hybrid. The pale yellow-green skin of a pomelo cuts away to reveal an inch-thick layer of skin that houses blushingly pink segments with a sweeter flavor than grapefruit. The segment membranes are extremely bitter, so the best way to eat them is by unsheathing each segment from its wrapper by hand or with a knife (a surprisingly satisfying task). Pomelo segments are wonderful on their own, but their mild, juicy flavor plays especially well in salads and fresh salsas.

8. Bergamot: These oranges -- and they are oranges, despite looking just like lemons -- are most famous for their use in Earl Grey tea. Intensely fragrant with a heady, floral, bitter aroma, bergamot oranges are spherical and yellow, with knobbly skin. If you're lucky enough to spot any at market, snap them up and savor every bit of zest and juice! They're a wonderfully unique addition to your normal run of citrus desserts, breads, and juices.

There are so many types of citrus that we had to pass over: Seville oranges, Citron, Valencias, and all the varieties in between. If you'd like to hear more about a particular variety, chime in with a comment, and be sure to come back next week for a look at tiny citrus -- lemons, limes, and kumquats galore!

Photos by James Ransom