'Tis the season for winter citrus!
Before the year-round ubiquity of the supermarket orange, December heralded the navel, tangerine, satsuma and clementine season. And it's still the time when citrus is at its peak, its bright hue and golden taste a welcome if fleeting contrast to the dark days of winter -- a spark of sunlight in a time when the northern hemisphere has so little. Get 'em while they are here!
Oranges are so closely linked to Florida and California that it's easy to forget they are a non-native species. In fact, they were introduced by Spanish colonizers in the 16th Century by way of Portuguese merchants trading with Far East. Orange trees flourished in Florida's subtropical environment and by the late 19th Century, the roots of the citrus industry as we know it today had taken hold.
Previous to their spread to Europe and the Americas, oranges were cultivated as ornamental plants and for their medicinal properties. In fact the orange is thought to have originated in Asia around four thousand years ago, but we probably wouldn't recognize the modern orange's forebears.
Citrus has also played an interesting role in globalization, whether through imports from the east during the Age of Discovery or its use as a curative for sailors suffering from scurvy -- a vitamin C deficiency -- during prolonged ocean voyages. As world trade has advanced, so has their dissemination, from the Silk Road to modern air freight. It wasn't really until the industrialized era that oranges became so readily consumed in the form of orange juice, the rate of consumption growing sharply since the 1980s.
Orange trees are generally not grown from seed as many hybrids are infertile or seedless. Instead rootstock is grown from seed -- something hearty and disease resistant -- and branches from a desirable variety are grafted onto the mature rootstock. It's one of the reasons why there are so many hybrids in the citrus family. The process of cloning is a common practice with all fruit trees. If it sounds a little complex, here's a good video of the process. There are exceptions, of course -- the satsuma, which is grown from seed, will produce fruit after eight years.
In the United States, winter is peak citrus time and the market saturated with the harvest from Florida and California orange groves. The difference between Florida and California is that the bulk of the oranges produced in Florida are pressed into juice while the bulk of oranges grown in California are for fresh consumption. When oranges are not in season, they are generally imported from South Africa, Chile, Mexico and Australia. Here's a good citrus calendar so you know what to look for during peak season!
Orange trees require a lot of water and are shipped all over the place, so unless you're in California or Florida, the humble orange racks up quite the environmental footprint. The citrus industry uses rather a lot of chemicals, too -- the Environmental Working Group lists oranges in the middle of their list for pesticide load. (See our vegetable rule of thumb at the bottom of this post.) Another reason to buy organic, but mostly, to cherish that tangerine in your stocking and don't waste it -- a lot went into it!
Oranges come in many sizes, but are generally no bigger than the palm of the hand. The smallest are generally your tangerines and mandarin oranges while navels are at the larger end of the scale. As the fruit ripens, orange oil is released from the pores of the skin giving the orange its characteristic fragrance.
Oranges are an excellent source of vitamin C, with one serving providing 90% of the recommended daily value. Vitamin C is a powerful antioxidant, which prevents cell damage and boosts the immune system. Oranges also contain a compound called limonin, which laboratory tests have shown to fight cancer. They are also a good source of the thiamin and folic acid.
Select oranges that are of medium firmness. If the fruit is too hard or has green spots, it is not yet ripe. If it is too soft or bruised, it is past its prime. All citrus should feel juicy when gently squeezed. Some oranges, like the satsuma and tangerine, have leathery flesh that is loosely connected to the sections of fruit inside. They are easily peeled while other orange varieties require vigorous attention to remove the fruit from the pith (the white part) and the peel. Select oranges that also smell sweet and fragrant and have a heaviness to them. Unfortunately color is not always an indicator of quality -- some oranges are dyed to fool consumers!
Citrus is best consumed right away, but some varieties will keep for four to six weeks in the refrigerator.
I confess -- I never really cook with oranges -- but I think that's okay. I propose that oranges are best consumed out of hand, savored in a perfumed cloud of orange oil released from torn bits of peel. But they are also delicious in salads, pressed into orange juice, or sliced up into sangria. Orange zest lives up to its name in the dreary days of winter, brightening up holiday cocktails, cakes and muffins alike.
Oranges can be turned into a preserve as marmalade -- a good way of using the whole orange, including the peel. Another way to stretch your orange bounty is to press it into juice and freeze it.
Here's how to get that fancy membrane-free slice you get in your salad at swankier restaurants. Ecocentrists may find this method wasteful because so much fruit stays stuck to the peel (it's probably not much worse than juicing, though) and should consider using the fruit first for zest, which (pro tip #2!) is easier when the peel is still intact.
From Bon Apetit
1 1/2 cups sugar
1/3 cup fresh blood orange juice
1/3 cup fresh lemon juice
6 large eggs
2 large egg yolks
1 tablespoon grated blood orange peel
1/2 cup (1 stick) unsalted butter, cut into 8 pieces, room temperature
1 1/2 cups all purpose flour
2 tablespoons sugar
1/4 teaspoon salt
1/2 cup (1 stick) chilled unsalted butter, cut into 8 pieces
2 tablespoons whipping cream
1 large egg yolk
Orange caramel sauce
2/3 cup sugar
1/4 cup water
1/2 cup fresh blood orange juice
1/2 teaspoon grated blood orange peel
For orange curd:
Whisk sugar, orange juice, lemon juice, eggs, egg yolks, and orange peel in medium metal bowl to blend. Add butter; set bowl over saucepan of simmering water and whisk constantly until curd thickens and instant-read thermometer inserted into curd registers 175°F, about 12 minutes (do not boil). Remove bowl from over water. Press plastic wrap directly onto surface of curd; chill at least 1 day and up to 3 days.
Blend flour, sugar, and salt in processor. Add butter and cut in, using on/off turns, until mixture resembles coarse meal. Add cream and egg yolk and process until dough clumps together. Gather dough into ball; flatten into disk. Roll out dough on floured surface to 13-inch round. Transfer to 10-inch-diameter tart pan with removable bottom. Fold dough overhang in and press onto pan sides, forming double-thick sides. Pierce crust all over with fork; freeze 30 minutes.
Preheat oven to 375°F. Bake crust until cooked through, about 30 minutes. Cool crust completely in pan on rack. Spread curd evenly in cooled crust. (Can be made 1 day ahead. Cover; chill.)
Cut peel and white pith from oranges. Using small sharp knife, cut between membranes to release orange segments. Transfer segments to paper towels and pat dry. Arrange orange segments in concentric circles atop orange curd. Chill tart up to 1 hour.
Remove pan sides. Cut tart into wedges. Drizzle lightly with Orange Caramel Sauce and serve.
For orange caramel sauce:
Combine sugar and 1/4 cup water in heavy small saucepan. Stir over medium-low heat until sugar dissolves. Increase heat and boil without stirring until deep amber color, occasionally brushing down pan sides with wet pastry brush and swirling pan, about 8 minutes.
Carefully add orange juice and orange peel (mixture will bubble vigorously). Stir over low heat until smooth and any caramel bits dissolve. Cool completely. (Can be prepared 1 day ahead. Cover and let stand at room temperature.)
(*Vegetable rule of thumb: We think that first and foremost, in terms of nutrition, people should eat lots of fruits and vegetables whether they are organic or not. The EWG's guide is a handy list, but we will point out here that the impacts of pesticides are not limited to your ingestion of them -- agricultural chemicals also affect farmworkers and local waterways, both good reasons to buy organic, even those vegetables that carry a light pesticide load. Also, it has been demonstrated that produce grown by small-scale farmers, even those who are not certified organic, tends to have a lighter pesticide load than its industrially-produced counterpart, owing to industry's tendency toward large monocrops.)
This post was originally published in December 2012.