Five years ago, a Ventura woman noticed a baffling phenomenon. One limb of her Valencia tree, which had always borne normal oranges, displayed shocking scarlet fruit. Was someone trying to poison her?
Before calling the police, she turned to Nick Sakovich, a local farm advisor, and asked him to take a look at the fruit.
To her relief, he identified the red oranges as a rare but spontaneous mutation--a "sport," in horticultural lingo. In fact, her Valencia had reenacted the birth of the blood orange in Sicily three centuries earlier.
Europeans have long prized this fruit's appealing blush, intense berry-like flavor and complex, lingering aftertaste. Few Californians remember, but before navels and Valencias dominated the market, blood oranges flourished here too. In the last decade, reversing long neglect, locally grown bloods have again become widely available. They're at peak quality right now, and if you know what and where to buy, you'll taste what many fruit aficionados say are the world's finest oranges.
Blood orange coloration is part science, part mystery. Cold winter nights alternating with mild days favor the development of anthocyanins, red pigments that impart a distinctive appearance and taste; shaded or partly exposed fruit, as on the north side of trees, tend to develop the darkest peels. Anthocyanins also color cherries, berries, beets and roses, indeed many plants. In young citrus leaves, the pigmentation protects delicate internal cells from sunlight, but in blood oranges it seems to be a superfluous response to climatic stress.
To the vexation of growers, the color varies unpredictably from season to season, from tree to tree and even within a single cluster of fruit.
A rosy rind is no guarantee of dark flesh, but one farmer, Bob Polito, claims he can tell when a Moro, the leading variety, is dark inside. On a tour of his grove in Valley Center, in north San Diego County, he points out fruit with a light chocolate-gray tinge in the pores of the peel.
"It looks like the color is seeping out from the inside; don't be fooled by a pretty red blush," he declares. His eyes twinkling, he unfolds a fruit knife and slices half a dozen maroon-fleshed oranges that corroborate his theory.
Some Moros grown in the San Joaquin Valley have such deep violet pulp--almost black--that they taste more of cherry or raspberry than of citrus. Though dramatic, these dusky beauties often have lost acidity and thus taste flat; when over-mature, they also develop an unpleasant musty aroma. Fruit with flesh of a medium burgundy color or lightly streaked with red usually offers a better balanced berry-orange, sweet-tart flavor.
About 350 of the 500 acres of blood oranges in California are in a strip along the eastern edge of the Central Valley, next to the Sierra foothills, from Bakersfield to north of Fresno. In this microclimate, dangerous frost-laden air drains down to lower elevations, but it's still chilly enough to produce deep-colored bloods.
Just after Thanksgiving, many commercial producers, seeking high prices for an early harvest, pick the first fruit with acceptable internal color, though it tends to be sour. Prime season for San Joaquin Moros runs from Christmas into March, when the fruit is typically large and dark, with a thick, bumpy rind.
Although large commercial packing houses pay no premium for top quality, a host of small growers in San Diego County, many with small organic groves, sell their crops at specialty and farmers' markets, where customers are choosy. They generally produce smaller, thin-skinned blood oranges, lighter in color but remarkably intense in flavor.
"We wait until the fruit gets really ripe," boasts Bill Hahlbohm of Sundance Natural Foods, who has grown and packed bloods for more than 20 years.
The South Coast season starts in January, peaks from February to April and extends into late spring. At the handful of groves in the Riverside and Ojai regions, the quality is also superb.
More than 95% of California blood oranges are Moros, favored by growers because the trees are vigorous and productive and the fruits "color up" most reliably. However, they vary so greatly in appearance that there's no such thing as a typical Moro. They range from round to oval, from golf ball to softball size, from vermilion to light ruby, with a smooth or coarse rind.
The Tarocco variety is much rarer in California than the Moro, but growers who know both almost always prefer the taste of the Tarocco. Sweeter than the Moro, with fine, tender flesh, rich flavor and exquisite fragrance, it ranks among the world's finest dessert oranges.