In October in the Northern Hemisphere, the kudzu leaves on the slope past the garden fence begin to fade to yellow. All summer the vines raced through the heat and humidity. Now they stop growing, and starch starts to build up in the roots underground. Kudzu is a woody vine in the legume family, and the part you eat is the thick root that grows deep into the soil. Simmer the root and you get tea. Let its starch settle out and collect it, and you get galbun, or kudzu root starch. The tea and the starch go with different ingredients.
A Root Dug from Late Fall to Early Spring
Kudzu root is dug once the leaves have dropped and on into early spring, which is November through the following February in the Northern Hemisphere. The roots are said to hold the most starch at this time of year, and that's why galbun has traditionally been made in this season.
The first thing to know about kudzu root is that it's full of starch. Your body breaks starch down into glucose as you digest it and uses that for energy. The root also contains dietary fiber. Chew a raw piece and a little sweetness comes out first, but tough fibers stay in your mouth afterward. Analyses have also repeatedly isolated isoflavone compounds from the root, including puerarin, daidzein, and daidzin. Some studies show that the amounts vary depending on the part of the plant and when it's harvested. Keep in mind that these analyses only show which compounds are present. They don't show what those compounds do in the body when you eat them.
Kudzu grows best at 20–30°C (68–86°F) on sunny, south-facing slopes. It grows widely in China and also grows wild in Korea, Japan, and Russia. You can divide and plant the roots in March or April in the Northern Hemisphere. But the roots go more than 1 m (about 3 feet) deep, which makes them hard to dig, and the vines spread quickly. In some places, like the southeastern United States, kudzu has spread so much that it's now a target for removal, so check your local rules before you plant it. For cooking, it's much easier to buy dried kudzu root or kudzu starch.
Kudzu Tea: Jujubes and Honey, with Ginger at the End
Kudzu simmered on its own leaves a bitter, astringent aftertaste. Add jujubes (Korean red dates) to the pot and finish with honey, and that aftertaste softens. When you buy dried kudzu, choose thinly sliced pieces. The thinner they are, the faster they steep.
- Put 20 g (about ¾ oz) of thinly sliced dried kudzu root and 3–4 pitted jujubes in 1 L (about 1 quart) of water and bring it to a boil.
- Once it boils, turn the heat down and simmer gently for a little over 30 minutes. A gentle simmer keeps more of the aroma than a hard boil does.
- Just before you turn off the heat, add two or so thin slices of ginger. Their warm, spicy aroma makes the tea easier to drink. Ginger gets hotter the longer it cooks, so turn off the heat soon after adding it.
- Pour the tea into cups and stir in honey a little at a time until it's as sweet as you like.
Start with these amounts and this simmering time, then use more or less kudzu and simmer it longer or shorter to suit your taste.
Kudzu Starch: Buckwheat or Wheat Flour, Plus Honey
To make galbun, freshly dug roots are pounded and pressed for their juice. The juice is stirred into water and left to settle, and this is repeated several times. Only the sediment left at the bottom is collected and dried. The fibrous pulp gets strained out along the way, so galbun has much less fiber than the root and is almost all starch.
Galbun doesn't hold together well on its own. So when it's made into noodles, it's kneaded into a dough with buckwheat flour or wheat flour. Buckwheat adds its nutty, earthy aroma. Wheat adds gluten, which binds the dough so the noodles break less easily. Once the kudzu noodles are cooked, try rinsing them in cold water and serving them chilled, or adding them to a warm broth.
Galbun is also used to make dasik, Korean confections made by kneading grain flour or starch with honey and pressing the dough into patterned molds. Mix galbun with honey and press it into the molds. The result tastes nothing like kudzu tea, which is brewed from the root, and you eat it in a completely different way.
Galgeun in the Dongui Bogam
The Dongui Bogam (a Korean medical encyclopedia published in 1613) lists kudzu root under the name galgeun (葛根) in its section on herbs (草部). It describes the root's nature as neutral and adds that some consider it cold. It records the taste as sweet and says the root is not toxic. It also gives another name for the plant, nokgwak (鹿藿). The text says to dig the roots on the fifth day of the fifth lunar month and dry them in the sun, and it calls roots that grow deep in the ground the best.
That date seems to apply to roots meant to be dried for medicine. It's a different season from the late fall to early spring window for digging roots to make galbun. Old medical texts often disagree with what we know today, so enjoy kudzu tea and galbun as seasonal foods, not as medicine.
Source: Dongui Bogam, 草部 葛根 (Herbs section, Galgeun)
On your next grocery run, pick up 20 g of thinly sliced dried kudzu root and a few jujubes, and make a pot of kudzu tea.
