I learned this the hard way after a surprise bumper crop of Jerusalem artichokes in my northern California garden last year. I had acquired a handful of these knobbly tubers at a neighborhood crop swap, and out of idle curiosity stuck them in my backyard soil – and promptly forgot about them.
One of the author’s personal sunchoke plants. The plant grows tall above ground and produces yellow flowers (see below), but underground, it’s a mess of these knobby tubbers. PHOTO: Kristan Lawson
Within months, ten-foot stalks towered over my yard, and at harvest time in late fall, I discovered that the stalks’ underground tubers had replicated themselves exponentially. (Under the right conditions, sunchokes grow so prolifically that they’re sometimes considered an invasive species.) I found myself digging up bucketloads of tennis-ball-sized tubers, which when roasted, sautéed or boiled at first tasted heavenly – yet then, a few hours later, caused spasms of pain and auditory embarrassment at the other end of the alimentary canal. I became determined to find a way to cook these delicious little devils in such a way that they didn’t cause flatulence.
Here’s what I learned:
The Culprit: Inulin
Ironically, the very thing that makes Jerusalem artichokes delicious and healthy is also the source of their unfortunate intestinal effects: inulin, an unusual type of carbohydrate that has recently become a trendy prebiotic supplement for gut health. Plants naturally containing inulin – and Jerusalem artichokes have a higher percentage of inulin by weight than almost any other vegetable – are naturally sweet and satisfying, yet have almost no functional calories since humans can’t digest inulin. But when enough inulin reaches the lower part of the intestinal tract, bacteria gobble it up and produce methane – which explains the brutally accurate nickname “Jerusalem fartichokes.”
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Tuber…or Not Tuber: The Basics
Jerusalem artichokes are neither artichokes nor from Jerusalem, but instead are the underground tubers of a tall plant closely related to sunflowers (for which the Italian word is girasole, phonetically bastardized to “Jerusalem” in English). They taste almost exactly like artichoke hearts, but with the satisfying starchiness of potatoes. (To avoid the cumbersome and confusing name, some retailers market them as “sunchokes,” a portmanteau of “sunflower” and “artichoke.”)
Jerusalem artichokes are neither artichokes nor from Jerusalem. They’re the underground tubers of Helianthus tuberosus, a tall plant (above) closely related to sunflowers. The Italian word for sunflowers is girasole, phonetically bastardized to “Jerusalem” in English, hence the name. The vegetable is also called a “sunchoke” – a portmanteau of “sunflower” and “artichoke.” PHOTO: Drop of Light / Shutterstock.com
As generations of cooks have learned through trial and error, no matter what you do to sunchokes – fry, boil, roast, braise, blanche, steam, simmer for hours or blast with high heat – their inulin will get you in the end.
How Much Is Too Much?
In my quest to de-gas my mountain of homegrown sunchokes, I learned that the problem was dosage: inulin become problematic only if you eat a lot of it.
“We regularly feed volunteers in nutritional trials up to 20 grams per day of inulin without significant problems,” says Bob Rastall, a biochemistry expert and Professor of Food Biotechnology at England’s University of Reading. “The issue with Jerusalem artichokes is that they can contain a lot of inulin – as much as 30 percent by fresh weight. It would be easy for a casual diner to consume enough inulin in one serving to cause problems.”
He’s not kidding: the average sunchoke tuber weighs about three ounces, or 85 grams; if it’s 30 percent inulin, that’s 25 grams of the gas-maker right there, already over the daily clinical dose. And who cooks only one tuber? I routinely would cook several at a time, just as I do potatoes. Is there any way to battle the inulin situation?
The Acid Test: A Way To Fart-Free ‘Chokes?
While researching my problem, I eventually stumbled upon an obscure folk custom that claimed to solve the vegetable’s seemingly intractable gas problem.
I learned that indigestible polysaccharides such as inulin can be converted to digestible sugars by “acid hydrolysis.” In layman’s terms, that means bathing the inulin in something watery and acidic. Lemon juice, perhaps?
Related: A Guide to the Roots and Tubers You Didn’t Know You Loved
These tubers are known to cause flatulence, but if you cook them in lemon juice instead of plain old water, you’ll get a less embarrassing – but equally tasty – outcome. PHOTO: viki2win / Shutterstock.com
Sure enough, that’s just what this centuries-old recipe for rendering Jerusalem artichokes fart-free – and one of the few methods of preparation I hadn’t tried – called for: boiling them in lemon juice. Modern science concurs: “Boiling Jerusalem artichokes in an acid such as lemon juice or vinegar will hydrolyze the inulin to fructose and small amounts of glucose,” Rastall advises.
So I gave it a try, boiling quarter-inch-thick sunchoke slices for 15 minutes in just enough lemon juice to cover them. They turned out amazingly sweet and still delicious, although – as Rastall had warned – they’d lost some of their artichoke flavor. But the stove-top hydrolysis worked: Eating a heaping bowl of lemon-boiled sunchokes produced no intestinal after-effects whatsoever. Success! (Boiling them in vinegar also hydrolyzes the inulin, I discovered, but leaves them with a harsh, astringent taste.)
Option 2: Pickle the Problem Away
Here’s another solution: Traditional fermentation-style pickling also removes sunchokes’ gaseous effects – while retaining their artichoke flavor. Gardening mavens Linda Ziedrich and Rose Marie Nichols McGee developed a game-changing recipe that yields completely gas-free Jerusalem artichoke pickles that keep all their wonderful crunch and taste.
Related: 10 Drought-Tolerant Plants to Have a Bountiful Garden – With Less Water
How? During this pickling process, lactobacillus bacteria gorge on the inulin and convert it to gas, which manifests as bubbles in the pickling jar, rather than your intestines. By the time the pickles are ready to eat, the inulin has already been mostly consumed, and the “bacteria farts” float away painlessly when you open the jar.
A Little Inulin Is Still Your Friend
Rastall, for his part, remains a vigorous advocate for inulin and its prebiotic benefits: “I’m interested in getting people to consume more prebiotics such as inulin on a regular basis.” His fix for the overdose of inulin in Jerusalem artichokes? Build a tolerance. “Rather than avoiding all inulin, I suggest that people consume small quantities on a regular basis,” he notes. “Their gut microbiota will adapt – the proportion of beneficial bacteria will grow, while the gas-producing bacteria will diminish – and after a while they will be able to eat Jerusalem artichokes without discomfort.”
Luckily, according to Rastall, both the hydrolysis and pickling methods retain enough of the inulin for health-inducing prebiotic effects, but not enough to give you gas, even with a substantial serving.