From the Pantry: Citrus
In the darkest days of winter, bakers yearning for fresh produce are rewarded with the colorful bounty of citrus season. Ruby Red grapefruit, maroon blood oranges, verdant Key limes, sunny yellow lemons—it’s a rainbow of edible sunshine. Whether juiced, zested, or left whole, citrus brings bright acidity and sweet tanginess to the table. But each fruit of the citrus tree has its individual quirks and pitfalls.
Let’s begin with the most popular citrus fruit: the orange. Comprising more than half of all the citrus grown in the world, the orange family is divided into two main categories, juicing oranges and eating oranges. The distinctions between the two groups are numerous biological adaptations made over hundreds of years by growers. Juicing oranges, like Valencia, have thin skins, seeds (occasionally), and sweet juice. Eating oranges, like navel oranges, have thicker skins, making them easier to peel, and are seedless. On the flipside, navel oranges produce juice that can quickly go bitter right after extraction— within 30 minutes. When baking, navel oranges are a standard choice, as they are commonly found at grocery stores and yield good zest and juice if used immediately. However, when a baker needs to candy or bake whole slices, rind and all, like for our Sicilian Whole Orange Cake or our Old-Fashioned Blondies, we recommend using a thin-skinned variety like Valencia oranges.
Other beautiful orange varieties that bakers use for visual drama are the brilliantly hued blood orange and delicately pink Cara Cara orange. Tart and with a slightly floral, raspberry taste, blood oranges receive their electric color from cold nights during the growing season. Cara Cara oranges are basically pink-fleshed navel oranges, perfect for baking with and eating. Less commonly used for baking are mandarins, tangerines, and satsumas. Like navel oranges, these are prized for fresh eating because they’re seedless, intensely sweet, and have loose rinds. Although their tender segments make them better for mixing into fruit salads rather than cake batter, the sweet juice of these three would be an excellent base for a glaze or syrup. No matter what orange variety you pick up, note that these are the least acidic of the citrus family, showcasing only around 1% citric acid.
Next on the rung of the citrus ladder is the big and bold grapefruit. Notably more bitter than other citrus, grapefruit has long been paired with plenty of sugar to mellow out its slightly caustic flavor. First produced in Barbados, it quickly became a cash crop for Florida farmers in the late 19th century, with grapefruit juice being spun into sweet pies, bars, and curds. When World War II made sugar scarce, grapefruit farmers began pushing salt as a way to tame grapefruit’s bitterness. One retro ad proclaimed, “Grapefruit tastes sweeter with salt!” It’s not as far-fetched of a claim as it seems—salt does help make things taste sweeter, which is why we include it in all our baked goods. If you’re put off by grapefruit’s strong-tasting juice, you can opt to play with its zest. Our Citrus Poppy Seed Twists and Triple-Citrus Sheet Pan Shortbread make the most of the zest while sidestepping the signature bitterness. On the acidity front, grapefruit has more citric acid than oranges but less than lemons.
Speaking of lemons, these bright yellow fruits may be the most popular citrus to bake with, and for many practical reasons, including that they can be found year-round at the grocery store. The most prized lemon varietal is the Meyer lemon. Golden yellow and verging on orange, the Meyer lemon is thin-skinned, aromatic, and less acidic than the typical lemon. The thin rind makes it a particular favorite for upside-down cakes, where the rind can become candied. As a zest, lemons are incredibly versatile, adding complex flavor to anything from fruity to spicy, like our Lemon Crumb Bars. But where lemons really show their power is in their highly acidic juice. Lemon juice doesn’t just offer a burst of bright, tangy flavor to your baking. Take its many chemical functions in creating lemon curd. The large amount of citric acid helps denature the egg proteins, giving it a silkier texture. The citric acid also helps kill harmful bacteria like salmonella and keeps the mixture from turning brown during oxidization.
As much as lemon juice can help, though, it can also harm. If directly added to eggs, lemon juice can cause the mixture to curdle. To combat this, most curd or lemon custard recipes, like the one for our Mile-High Lemon Meringue Pie, call for whisking the eggs with sugar before adding the lemon juice. The sugar protects the egg proteins from premature coagulation. A similar balancing act is needed when adding lemon juice to cakes or quick breads. Lemon juice tenderizes everything it touches, weakening the gluten structure to the point of destabilization if you’re not careful. Consider working in tablespoons rather than in cups. For this reason, lemon juice (and equally acidic citrus juice) is often not used in yeasted bread recipes, as the citric acid destroys crucial gluten development. Our Citrus Poppy Seed Twists use zest rather than juice to convey rich citrus flavor. The only lemon juice used is in the glaze.
Our final member of the citrus family is also the most acidic: limes. Nearly 8% of their chemical makeup is citric acid, making limes supremely tart. Persian, Bearss, or Tahitian limes are the most commonly found variety in the grocery store, but the diminutive Key lime is also popular in Florida and other Southern states. However, if you’re looking to recreate an authentic Key lime pie or our Key Lime Doughnuts, we recommend skipping the
manual juicing of Key limes. It can be a literal pain to juice these tiny fruits, and we find store-bought Key lime juice, like Nellie & Joe’s Famous Key West Lime Juice, works just as well as fresh squeezed juice.
These are the individual nuances of citrus varieties, but there are all-encompassing rules that you can use as well. Citrus (an acid) works well with baking soda (a base). The two neutralize each other to keep any off-flavors from occurring in the baked good and help add
brown caramelization to the baked good’s crust. The more acidic the citrus, the more important that baking soda be present. The porous skin of the citrus makes it prone to picking up undesirable aromas and flavors, and a good rinse before peeling or zesting is advised. Speaking of zest, keep in mind that all the flavorful oils you’re hoping to extract from the rind doesn’t include the white, spongy part, a.k.a. the pith. The pith is incredibly bitter and can ruin the overall fl avor of your zest. When you’re making candied citrus peel, the pith is included, but recipes often call for boiling the peel segments before candying to remove any lingering bitterness. With all the sweet benefi ts of baking with citrus on display, there’s little wonder that it endures as one of the warmest highlights of the winter season.
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