The Secret to These Noodles Is an Obscure Chinese Desert Plant

"We use a plant called penghuicao to increase the elasticity of the noodles," Zhaohong Li says. "It grows in the desert."

Li is the headmaster of a beef noodle soup school in Lanzhou. Hand-pulled noodle soup with beef is the trademark dish of Lanzhou, the capital of the Gansu province of China. The dish is so ubiquitous that shops sell the soup on nearly every street corner. The noodles are known for their malleability; they stretch to abnormally long lengths and can be shaped to many different widths depending on the preference of the customer.

"Wait, what?" I ask in complete surprise.

I had thought that noodles were basically the same around the world. The core ingredients: flour, water, sometimes egg, maybe a little bit of salt or an alkaline agent. It never occurred to me that a desert plant would be on the list.

"It is an alkaline substance," Li says.

The scientific name of penghuicao is Halogen arachoideus, a plant found in desert ecosystems in northern China on sandy areas. It grows locally in the northern Chinese province of Gansu, which has a generally arid climate. The province is also the home to parts of the Gobi, Badain Jaran, and Tengger deserts.

"The leaves of Halogen arachnoideus have a relatively large concentration of calcium oxalate as well as potassium, sodium, and calcium," Selena Ahmed, ethnobotanist and an assistant professor of sustainable food systems at Montana State University, says.

Traditionally, the plant is roasted, compacted, and then dissolved into a flour and water mixture. Today, most of the powder is made in factories.

"Humans have taken advantage of these minerals for culinary purposes by burning or roasting Halogeton arachnoideus into an ash or potash to obtain a soda for preparing foods," Ahmed says.

The crude ash content of Halogeton arachnoideus is over 35 percent, which imparts an alkaline component that increases the pH level of the noodle dough. This allows for greater absorption of water in the flour and helps with starch degradation.

In short, the plant makes the dough more elastic, which makes it easier to pull.

"These processes ultimately serve to strengthen the structure of the protein of egg noodle dough and its extensibility," Ahmed says. "With a stronger and more extensible noodle dough to work with, skilled noodle makers can apply their artful skill of stretching the noodles to great lengths."

For years, the use of penghuicao in Lanzhou beef noodles was considered an industry secret. In 2011, a Nanjing television station exposed it as an essential ingredient—angering noodle joints across the country.

Lanzhou isn't the only city to use desert plants as a secret ingredient. There are many arid towns throughout Northern China that use the local vegetation to enhance their noodles. Noodles, after all, are the main carb of the north of China and have been a part of the Chinese diet as early as the third century. Unlike the south of China, which grows primarily rice, wheat is the main crop up north.

In the town of Zhongwei in the Ningxia Hui Autonomous Region, just east of Gansu, there's a dish called haozhi noodles, enriched with the seeds of a local plant. At first glance it looks any another other wheat noodle—thin, long, and chewy. Made with flour, water, and bits of haozhi powder, the noodles are served in earthy herbal broth with chunks of beef. There are faint specks of grey in the dough; this is the haozhi.

When I visit the Tengger Desert on the border of Inner Mongolia and Ningxia on a camel trek, the guide points to a cluster of sharp shrubs nestled on the sand dunes.

"This is haozhi," Changhe Wang says. "It's used to make haozhi noodles."

Wang is a tour guide in the Tengger Desert but grew up as a herder in the sand dunes of Inner Mongolia raising camels, horses, and goats. Sand dunes don't have a reputation for being fertile, but this particular area is a rich ground water source that dates back to the Tertiary geological period. Wang was hired as a consultant to dig 40 wells nearly 590 feet down. On our trek we encounter edible, wild seaberry and a continuous cluster of haozhi. Sand dunes, as it turns out, are full of culinary gems.

"People use the seeds of the plant to make noodles chewier," Wang says.

The scientific name for haozhi is Artemisia desertorum. "The seeds of Artemisia desertorum are comprised of an edible gum and pectin, which are natural plant fibers," Ahmed says. "These plant fibers can bind with ingredients in noodle dough to yield a more elastic texture."

Artemisia desertorum has also been found to have beneficial health properties. Ahmed notes that it has been studied as an ingredient to make noodles with a relatively lower glycemic index than standard noodles.

In the town of Wuwei, just 170 miles north of Lanzhou, there is a dish known as shamifen, or sand noodles, made out of the seeds of a plant called shami. The noodles are clear, like jelly, but don't have much resistance. In most restaurants, they are simply marketed as cold jelly noodles. This doesn't say much. Jelly noodles in China can be made with a variety of substances like wheat, mung bean, yam, or sweet potato. But in Wuwei, they are made entirely out of shami. It's blanketed in vinegar and chili sauce and served two ways—either cold or fried to a crisp.

"[Shami] refers to the seeds of Agriophyllum squarrosum," Chunlin Long, a professor at the Kunming Institute of Botany, says. "In Gansu Province, some local people collect the seeds to make noodles."

The seeds of the plant are collected, soaked, and then milled into a flour to make a jelly-like substance.

"Agriophyllum squarrosum is another species that has evolved unique characteristics in its adaptation to surviving in arid, semi-arid, and sandy conditions. This is an extremely drought- and heat-tolerant species," Ahmed says. "It is chock-full of nutrients for humans, including a rich protein and amino acid profile. In fact, it has the full range of essential amino acids for the human diet."

The noodles also have a cooling effect and are especially popular during the summer.

Back at beef noodle school in Lanzhou, Li patiently bears with me as I pepper him with questions about noodles and desert plants. While the noodles of Northern China are famous, few people know what goes in them.

"Honestly, most of the penghuicao is chemically manufactured these days," he says when I ask him if he can show me the plant.

The same narrative seems to repeat itself as I travel through Northern China. In Zhongwei, haozhi powder can only be found in specialty grocery stores and locals in the Gansu Province tell me that shamifen is increasingly rare.

It's cheaper to buy and manufacture alkaline agents, and in the case of shamifen, easier to substitute with a more readily available ingredient like mung bean or potato.

"My grandmother used to make shamifen all the time when I was a kid," Vicky Zhao, a Lanzhou native, says. "It's harder to find these days. Few people can tell the difference between shamifen and regular jelly noodles."

She adds, sadly: "These days, less and less people know how to make their own noodles."