I tasted my first macadamia nut years ago on a Pan Am Clipper flight to Honolulu. Pulling a kernel from the tiny, shiny blue triangular package that had been handed to me by a flight attendant wearing a hibiscus-print dress, I discovered a new sensation of flavor and texture. It was love at first bite.

Unfortunately, macadamias (or "macs," as they are often called) have become an endangered species on airlines. "Too expensive," a flight attendant recently told me on a jet bound for the Big Island, home of the state’s macadamia industry. Though occasionally grounded as airplane fare, the cream-colored nuts now appear in ice cream, cookies, pies, muffins, candies, coffee, bread, pancakes – even in haute cooking at fancy Hawaiian restaurants. These days, macs are as hard to avoid in the islands as mai tais, leis, and sunburn.

Not long ago it occurred to me that despite having spent nearly two decades on Oahu – just a few islands down the chain from the largest macadamia grove in the world – I knew little about the nut. So when I heard about the "The Great Hawaiian Mac Nut Trail," which makes it easy to visit farms and even stay overnight at quaint bed-and-breakfast inns set among the groves of lush trees, I hopped a plane for Hilo.

Deciding to take the mac 101 course was easy; finding Randy Ahuna’s 36-acre macadamia farm a few miles southeast of Hilo was not. Stopping at a small bakery for directions, I got into the spirit of things by ordering a mac muffin and a cup of mac-flavored coffee, which I enjoyed while reading the trail brochure.

I learned that in 1882 Big Island sugar-plantation owner William H. Purvis had imported macadamias from Australia. Descendants of those nuts would later be used to establish the world’s first commercial plantations. I found out that the nuts thrive in Hawaii’s rich volcanic soil, abundant sunshine, and frequent rain. I also discovered that the macadamia-nut tree is an evergreen and must be at least 7 years old to bear nuts and can produce until the age of 50. The nuts grow in clusters along the branches and are not picked but harvested after they fall to the ground. A soft outer husk covers the inner shell, which you can crack only by applying 300 pounds of pressure, but carefully: The inner kernel has to remain intact.

Eventually I found the narrow lane that led from Highway 11, past thick rain forest on one side and modest single-story homes on the other, to Ahuna’s farm. There, neat rows of macadamia trees rose out of the smooth black lava from an ancient Mauna Loa flow. The trees’ pale green, tentacle-like roots wound their way through and around the porous lava, disappearing here, reappearing over there. It was a week before the August-through-December harvest season really got going, and the nuts were starting to fall.

I found Ahuna, who is half Hawaiian, sitting on a rusting metal chair under the corrugated metal roof of his small open-air husking and sorting plant, waiting out a rain squall.

"Let’s talk story," he said after he shook my hand and invited me to have a seat beside him. "Nothing to do until it passes."

As any conversation about macadamias will, ours soon got around to their famous hardness. Ahuna tossed me a husked nut, whose tawny inner shell still protected the kernel, and motioned to a vise on a nearby table. I placed the nut in the vise, then tightened and tightened until the pressure was enough to bust bone.

"One tough buggah, yeah," Ahuna said in island pidgin. Finally I heard a crunch, and a crack appeared, revealing the kernel within. Experimenting with another nut, I tried to smash it with a jagged lava rock: a dent but no crack. Then I threw it against a concrete slab. The nut bounced six feet into the air. I slammed it with a five-pound sledge. The nut shot out to the side, glancing off Ahuna’s rubber boot.

"Trying to kill me or what?" he said, laughing. Then he explained that because the nut is so hard, most small-scale farmers remove only the outer husk and leave the job of cracking the inner shell to "the big boys," like Mauna Loa Macadamia Nut Corporation, just down the road. "They got the heavy stuff," he said. "You should try look." I planned to.

When the rain stopped we climbed into Ahuna’s rusting blue pickup truck. "This is where it started," he said, turning into the grove of 2,000 trees, which yield about 400,000 pounds of raw nuts per year. "The best time of my life was growing up on this farm."

The Muna Loa macadamia nut corporation is to processing macadamia nuts what General Motors is to building cars. The company husks, dries, sorts, cracks, and packages some 150,000 pounds of nuts every day during harvesting season, and some 40 million pounds annually.

A large sign on the highway signaled the turnoff to Macadamia Road, which ran for a few miles through a 2,500-acre orchard of dark green, 60-foot-high trees and ended at a parking lot outside the visitors center and an enormous processing and packaging plant that was two stories high and as long as a football field.

Manufacturing Manager Mike Smith explained the whole process to me. Once the nuts are picked, he said, they are piled into carts that are hitched to a tractor and towed to the plant. After the nuts are washed and husked, a conveyor belt transports them to drying-tanks, where they spend up to two weeks before being cracked, roasted, packaged, and sent to market.

"This way to the crackers," said Smith, handing me a hard hat, then leading me through a catacomb of stairs, narrow catwalks, and low-hanging pipes.

The business end of the seven industrial-size crackers was fitted with two grooved 900-pound titanium balls that rotated in opposite directions and were separated by a space about as wide as a nut. As the nuts passed between the twin revolving spheres, the shells were cracked, hopefully leaving the kernels untouched.

"That’s about it," Smith said as we walked out of the plant and into the light of day. I asked him if any farmers cracked their own.

"Some do," Smith said. "There’s a guy in Pahoa who uses something that looks like a bazooka."

Christian Bernadzik and Monika Nauen run Mac’s Nut Co. of Hawaii as something of a "boutique" macadamia business, which includes the Mac’s Inn Hawaii bed-and-breakfast. I found my way to the property by counting highway mile markers rather than looking for an address.

"You vant to see zuh clackuh, right?" said the 33-year-old German-born Bernadzik before I could climb out of my truck.

Yes, I did. But first he insisted we visit the 15-acre, 1,100-tree grove that he and Nauen had rescued from desuetude. "At first we did it all, removing rocks, weeding, mowing, pruning, bagging," said Bernadzik. "I broke the riding mower in the first six feet because of all the lava rocks around the trees."

A few minutes later Bernadzik unlocked the garage door to reveal the computer-controlled F15 Starcracker. Invented by Bill Whaling, who lives in nearby Kau, the device resembled a bazooka, just as Mike Smith had said.

The operating principle was simple: Compressed air was used to shoot individual nuts through a rectangular barrel at 400 MPH. The nut struck an anvil, which knocked the husk off; then, a thousandth of a second later, a piston hit the nut, cracking the shell.

After watching the machine in action – it worked perfectly – I retreated to the inn. But as the sun set and I discovered that macs went well with chilled chardonnay, I could still hear the rat-tat-tat of the cracker and see Nauen’s silhouette in the sorting room. I shouldn’t have been surprised. "This is our life," she had said earlier. "Seven days a week, ten hours a day. Nuts, nuts, nuts."

The next morning I drove some 90 minutes through volcano country – and past the world’s largest macadamia orchard, at 3,850 acres – on my way to Maluhia. The 21-acre, 1,200-tree farm is owned by Anne and Dominic Abbriano, who bought the land 17 years ago when they moved from California. I met them at their two-story home, which overlooked the orchard and South Point, the southernmost point in the United States.

"We just wanted to grow something when we moved here," said 70-year-old Dominic, "and the macadamia nut is very forgiving of stupidity."

The Abbrianos are relaxed growers. They leave the tough business of cracking the nuts to a big processor. They enjoy the easy pace of island life. They are mac farmers as lifestyle seekers. "We created something out of nothing and have a quality of life most people dream about," Anne told me. "Maluhia is Hawaiian for ‘serenity, ’ and we have it."

Contributing editor Tim Ryan is a feature and entertainment reporter for the Honolulu Star-Bulletin newspaper.