Adventures with Almonds, Part I: The Marvelously Fragrant Hall’s Hardy Almond

This is the first part of a two-part series. I’ll publish the second, on making marzipan, shortly.

In the meantime, you might check out two articles I recently published with Mother Earth News, “Finally, a Good Thermometer for Home Preserving” and “Fun to Watch, Fun to Eat: Pickled Mixed Vegetables Brined in Glass.”


Hall’s Hardy almond tree

I finally got around to cracking last fall’s crop of Hall’s Hardy almonds, my biggest in the five years since I planted the tree. I had more than half a cup of nutmeats!

Hall’s Hardy is actually a peach-almond cross. But because it blooms late, resists fungal disease, and self-pollinates, it is considered the only almond variety suitable for growing in the Pacific Northwest. Or so it was considered until recently, when Jim Gilbert of One Green World introduced several Ukrainian almond varieties, all of which are said to have the same virtues as Hall’s Hardy, plus more: They are true almonds, with soft or semisoft shells. But the Ukrainian varieties are yet unproven in Oregon. For now, I’m grateful for my tiny almond harvest, especially because these almonds have something the soft-shelled true almonds almost certainly lack: the lovely flavor of almond extract—that is, the flavor of bitter almond.

Hall's Hardy in shellCracking a Hall’s Hardy almond is problematic. Once freed of its husk, the nut looks like a peach pit, and it’s just as thick and hard. I tried using a kind of nutcracker, meant for walnuts and pecans, that surrounds the whole nut; as you press the two arms together, the hinged central cup hugs and squeezes the nut inside until the nut breaks at the seam. I cracked two or three nuts with this cracker, and the small kernels, to my delight, turned out whole. And then the hinge sprang.

hammering almonds, bestSo I got out a hammer, an old bread board, and a dishtowel I’d consigned to the rag bin. With the hammer method it’s important not to use a board or a towel that you care about, because you’re bound to damage both. You place a few nuts at a time on the board, lay the towel over, and then bang, bang away. You remove the towel and collect all the nut pieces, most of them itsy-bitsy. And then you toss out a mountain of thick shell pieces and sweep the stray ones from underfoot before they damage your floor or your flesh.

By this point some of you dear readers no doubt feel alarm, and not about the dangers of stepping on nut shells. It’s my mention of the flavor of bitter almond, right? The essential oil of bitter almond is nearly pure benzaldehyde, a chemical that signifies the presence of amygdalin, which enzymes in the intestines convert to prussic acid, also known as hydrogen cyanide. And cyanide kills. Some scientists say that eating 50 bitter almonds will kill an adult; a child may die after eating only 5 to 10. Other stone-fruit kernels—apricots, peaches, and plums—contain the same flavor, the same chemicals, and the same deadly power.

Despite its toxicity, amygdalin has a long history as a medicine. In China, for example, apricot pits have been traditionally used for coughs and constipation. But amounts taken were probably miniscule before the 1950s, when amygdalin in the form of laetrile, or so-called vitamin B17, became a folk treatment for cancer. In the United States, the popularity of laetrile surged after 1972, when a researcher at Memorial Sloan-Kettering Cancer Center reported that the drug inhibited secondary tumors in mice. Although other researchers were unable to confirm these results, desperate cancer patients traveled to Mexico to buy laetrile or got their amygdalin directly from stone-fruit pits—especially from apricots, whose kernels, even richer than bitter almonds in amygdalin, are used as a food flavoring in Turkey, Tunisia, and elsewhere in the Mediterranean region. At least a few children who might have survived cancer succumbed to laetrile poisoning instead.

Because some people will apparently force down the bitterest pill or nut if they think it’s good for them, bitter almonds cannot legally be sold in the United States. You can buy “pure” almond extract, which may be made from apricot or peach pits, or almond paste, probably flavored with apricot pits if not a synthetic imitation, but you can’t sell the almonds.

Some businesses do sell them, however, and those businesses include Trader Joe’s and Costco. Or so say consumers of Marcona almonds from Spain. Apparently, a bitter almond or two appear now and then in a bag of roasted Marconas, a variety with rounded kernels that are especially rich in oil. One bite of a bitter Marcona leads to spitting and gagging and a foul taste in the mouth that lasts the whole day through. Or so say these startled consumers.

This never happens with California almonds. You might occasionally taste a rancid California almond, if your nuts have been stored for too long. A rancid nut may make you spit and gag, but rancidity is not the same as bitterness.

The problem with Spanish almonds is something biologists call xenia, after a Greek word for hospitality. Xenia happens when the pollen of a plant of one genetic strain affects the seeds and fruit of the fertilized plant. This effect is distinct from the effect the pollen has on the next generation. Xenia is the reason gardeners plant their sweet corn far away from any field corn, popcorn, or ornamental corn, even if they don’t plan to save seed for planting in a subsequent year. The pollen of any of these other types of corn could turn the sweet corn starchy. In the same way, ears of white corn pollinated by yellow corn will turn out yellow, and the kernels of popcorn pollinated by sweet corn will turn out sweet and, probably, shriveled.

In the United States, all our commercial almonds are grown in California, in Central Valley orchards so extensive that beekeepers from all over the country truck in their hives for winter forage (this annual gathering of the hives is largely responsible for the rapid spread of various bee pests and diseases across the continent). Blooming California almond orchards are a lovely sight to see, as you race up or down the interstate, but they are a picture of modern, industrial farming. No doubt Spain, the world’s second largest almond producer, has orchards much like them, but I haven’t seen them. Traveling through Andalusia one winter, I got a different view of almonds in flower. Masses of pale-pink blooms were scattered here and there over the landscape. The almond trees, some small and some towering, marked old fence lines, roads that might have been buried in sand, and other past and present boundaries where the trees had grown up from seedlings and thrived without care. Almonds have been growing here since Roman times. Although bitterness in their nuts is a recessive trait, controlled by a single gene, bitter almond trees dominate in numbers because critters avoid eating their nuts—that is, their seeds—and also, apparently, because sweet almond trees are less tolerant of very dry, sandy soil.

In Spain, sweet almond orchards are mostly planted in damper, coastal areas. But sweet almonds can also grow on irrigated land or on dry land without irrigation if the scions are grafted to bitter almond trees or to peach-almond hybrids. It is in these dryland orchards, I suspect, that xenia happens. The sweet almond flowers are supposed to be fertilized by the pollen of other sweet almond varieties that bloom at the same time and are interplanted in the same orchard. (Self-pollinated varieties are yet a novelty in both Spain and California.) Every once in a while, however, a bee carries pollen from an almond tree growing wild in the fencerow or anywhere else in the vicinity; honeybees, after all, often fly two miles from the hive in search of pollen or nectar. Xenia happens when a bee brings pollen from a wild, bitter almond tree to a sweet almond tree with a recessive allele, that is, an allele—or gene variant—that when matched with another recessive allele will cause bitterness. Marcona almonds, like most of the other varieties grown in both Spain and California, is heterozygous for sweetness. From the flower where the bee deposits pollen, a bitter nut develops.

The more bitter the nut, the more amygdalin it contains. A study of Spanish almonds found amygdalin ranging from 2.16 to 157.44 milligrams per kilogram in nonbitter almonds, 523.50 to 1,772.75 milligrams per kilogram in semibitter almonds, and 33,006.60 to 5,3998.30 milligrams per kilograms in bitter almonds. The least bitter bitter almonds, then, had 210 times as much amygdalin as the most bitter nonbitter almonds. The most bitter bitter almonds had 25,000 times as much amygdalin as the least bitter nonbitter almonds.

Given that my Hall’s Hardy almonds weren’t almonds at all but an interspecies cross, I didn’t know whether to classify them as nonbitter, semibitter, or bitter. (I will continue to call my almonds almonds, however, because genetists have determined that through millennia of development peaches and almonds have crossed repeatedly.) Because of their strong aroma of benzaldehyde, I figured that the Hall’s Hardies must contain more than a little amygdalin. I found an old gardening publication from Cornell University that recommended against growing either Hall’s Hardy almonds or another hybrid variety, called Ridenhower, because of the nuts’ bitterness and possible toxicity. But I could taste barely any bitterness over the strong benzaldehyde flavor of my nuts, and I tend to be sensitive to bitterness. They tasted so good, in fact—so much more interesting than California almonds!—that I would have tossed all the kernels into my mouth if I hadn’t had other plans for them.

My plan: I would make my own, no-flavor-added marzipan.

Gauging the Gages

plums from a dead nectarine

While picking apples yesterday I noticed that most of the leaves had blown off one of my greengage trees, the one that grew up from the rootstock of a dead nectarine tree. Among all my Prunus trees, this one’s fruits ripen latest. The little plums, as green when ripe as when hard and new, tend to hide among the leaves. Exposed to view now were three survivors, wrinkled but otherwise perfect. Picking one at a time, I slowly savored their buttery flesh. I will have to wait most of the year for another taste like that.

Plum trees are among the very best of the weeds with which the Old World has blessed the New. In California, cherry plums (Prunus cerasifera) are so ubiquitous that until recently I thought they were native (in fact, they are now considered an invasive species). When I was a child, grownups would plant certain cultivars for their purple-red leaves and then curse the fallen fruit on the sidewalks. Children loved every cherry plum tree, planted or wild and regardless of leaf color, for the sweet, juicy, mildly to strongly tart fruits, each a perfect mouthful. Like blackberries, these fruits belonged by rights to any child who could reach them, and mothers were obliged to turn every bucketful into jam.

Italian plums from roadside trees

The Pacific Northwest is too cold and wet for cherry plums, but we have our own sweet gift from Europe: the plum, or assortment of plums, that botanists call Prunus domestica. Back when fresh fruit was rare and dear in winter, large, oblong, blue-black fruits of P. domestica were big business in the Willamette Valley, because they are so rich in sugar that you can dry them without pitting them. They still are big business in California, in places where the orchards haven’t been replaced with vineyards, though the agribusiness publicists have banned the word prune and substituted dried plums for the dehydrated product. The main commercial variety in California is called French; Oregon farms grew Italian and Brooks. Although little commercial plum culture remains in Oregon, Oregonians are still enjoying fruits from the remnants of old orchards, along with occasional planted or wild P. domestica treesof other sorts—mirabelle, gage, and damson.

Just as I my little brother and I once brought home cherry plums for my mother to make into jam, my own children used to bring home wild yellow plums. Very different from juicy, tart cherry plums, these yellow plums were low in acid and creamy-fleshed, with a powdery bloom. I sometimes made them into a vanilla-flavored jam, like the jam I’d tasted in the home of a Spanish friend, who called the plums claudias.

This Spanish name comes from Reine Claude, the sixteenth-century queen of the French king Francois I, who named the honey-sweet plums in his wife’s honor. By the early seventeenth century a man named Gage had imported the favorite Reine-Claude cultivar, Reine-Claude Dorée, to England. Unlike its close relatives, which produce tasty but usually unremarkable fruit, Reine-Claude Dorée is said to bear plums that are fragrant as well as extra-sweet. Although related plums, like those from my nectarine rootstock, are often green even when fully ripe, Reine-Claude Dorée starts out green and ripens gold. In England, Reine-Claude Dorée became known as the true Green Gage, and its shirttail relatives as greengages or just gages (because they are not always green).

Mirabelles are similar to gages, but they’re a little smaller and quite yellow when ripe. Two cultivars, mirabelle de Nancy and mirabelle de Lorraine, are celebrated commercial crops in France, where they’re mostly used for jam and eau-de-vie. Although mirabelles belong to the subspecies syriaca, they cross freely with italica, the subspecies that includes the gages. I don’t know whether the yellow plums my children collected were gages or mirabelles or something in between.

One year a zealous farmer ripped out the roadside tree my children had been picking from, figuring, apparently, that the support its roots gave to the wall of the irrigation ditch failed to compensate for whatever nutrients they stole from his beans. So I told the kids I’d plant an even better tree, and bought a grafted greengage from the Home Orchard Society. I hoped this tree would turn out to be the famous Reine-Claude Dorée. A few years later, to my chagrin, the tree began producing fruit much like that of the roadside tree—very sweet and smooth-textured, with skin that ripened gold with tiny red speckles–but lacking in acid and fragrance.

In 2004 David Karp traveled to France in search of the true Green Gage and found that the cultivar is now a rarity there. It takes too many years to come into bearing; it crops erratically; its delicate fruits must be picked with extra care; and the rain causes the plums to crack and rot. As David reported in the New York Times, a French plum farmer told him that Reine Claude Dorée was “bizarre” and “capricious.”

The next best thing to Reine-Claude Dorée, say the French, is the cultivar that started as a seedling of Reine-Claude Dorée in Belgium, where it was discovered in 1832.  This Belgian gage, Reine-Claude de Bavay, produces fruit nearly as delicious as that of la vraie Reine-Claude but is less finicky.

A few years ago, I was able to buy both a Green Gage and a Bavay gage tree from One Green World, Oregon’s famed source for uncommon fruiting trees and shrubs. Though the deer regularly chewed off the leaves and tore the lower branches, and borers bored through the cambium, the trees seemed to thrive, and this past September they produced their first fruits. My mouth watered for a week as I waited for them to finish ripening. When they looked ready I wrapped my fingers around each fruit and tugged very gently. If the plum pulled away easily from its stem, it was ready to eat. If not, I’d try again the next day.

Green Gage—but not Reine-Claude Dorée

The so-called Green Gage fruits were a disappointment. With unspeckled green-gold skins, covered with a thick, dusty bloom, they were a little larger than the fruit of the Home Orchard Society tree, and they had the same wonderful creamy texture and sweetness when fully ripe. But their taste was flat.

Reine-Claude de Bavay









The Reine-Claude de Bavay plums were ugly. A little bigger than the so-called Green Gages, they ripened more green than gold, with a heavy bloom, rash-like red patches, scabby spots, and open cracks. But what a marvel in the mouth! Here was all the buttery texture of the other gages, a powerful honey-like sweetness, and a strong tartness besides.

Green Gages (left) and Bavays (right), their bloom rubbed away

I gave my husband one Bavay, and I ate all the rest as they ripened over the next few days. To heck with Reine-Claude Dorée; I had discovered a greengage I loved. I dreamed of next year’s crop, which was sure to be larger.

Two weeks after I finished off the Bavay plums, I found the tree on the ground. I was mystified at first, because we hadn’t had a storm or any strong winds. But the graft must have been weak—the tree had broken along it—and I could see borer damage at the break, too. I guessed a deer must have hit the tree, just hard enough to fell it, while leaping over the fence behind it.

I let the tree lie. Now it’s time to haul it away and decide: Should I plant another grafted Reine-Claude de Bavay, or should I try to get a scion to graft onto the healthy sucker that, presciently, perhaps, I let grow up over the summer?

And, just for the sake of comparison, should I try once more to find a real Reine-Claude Dorée?