From Japanese Forests to Your Feet ・ How Vinegar Is Extracted from Kumamoto Bamboo, and Used to Soothe Your Soles

A concentrated natural extract of Japan's abundant bamboo, bamboo vinegar is a unique ingredient that locals call "chikusakueki" (竹酢液). The prized liquid is smoked and roasted out of tall stalks of bamboo that tower high overhead in Japan's quiet bamboo forests, towering green columns left to grow high into the sky throughout the seasons. Over a number of days, bamboo vinegar producers will harvest the stalks and draw the sap out of the bamboo using traditional methods, bringing out its best properties by aging the extract for years on end. The final product is highly acidic, which is why it's called a "vinegar," but it also contains more than 520 different organic compounds, along with a variety of minerals. These unique properties make bamboo vinegar a valuable commodity in Japan, which has historically been used for everything from sterilization and deodorization, to medicinal or relaxation purposes. This smoky bamboo essence is a powerful extract with a powerful pull.

The process of making bamboo vinegar starts in the greenery of the Japanese countryside, where huge bamboo groves cover the hillsides and crowd up to the edge of the narrow roads. This bamboo is used for a number of purposes, including the farming of tender bamboo shoots, but the stalks used to make bamboo vinegar are only the tallest, broadest ones in the forest.

Bamboo vinegar makers harvest bamboo stalks that have been left to grow tall for four or five years ー a long time for the quick-growing bamboo ー and they carefully chop down one towering plant at a time, letting the long green columns fall right out of the crowded forest.
 

The basic preparation process for the bamboo takes days, as workers chop the stalks into more manageable lengths and split the thigh-sized logs into thin strips. Once the strips are flattened and straightened out, they're bundled into hefty armfuls and tied together with twine, then left to dry naturally for another half a year.

The next few steps are where the magic really happens, as the bundles of bamboo are first piled carefully to smoke away in a smokehouse, and then afterwards moved to a huge outdoor oven. The next part of the process is the most vital, and workers carefully keep an eye on the thermostat to make sure the bamboo strips are heated to a temperature between 80 and 130 degrees celcius. Any cooler or any hotter, and the finished product won't be up to scratch. When the bamboo starts to steam and release the gently smoked sap pent up within, streams of vapor flow out of the oven's chimney, and the mist is funneled into a pipe and collected as condensation.

This precious liquid is fresh bamboo vinegar, but even when the bamboo is all baked into charcoal and the steam is all collected, the new batch of vinegar still isn't quite ready. The liquid is refined over and over to remove impurities, and then left to age to bring out the bamboo vinegar's very best qualities, over the course of a number of years.

Bamboo vinegar is the hard-earned result of an arduous, years-long process of preparing bamboo, heating it, and carefully refining the steam it releases. Among its many uses, this sour, smoky, 100% natural liquid is added to a variety of products in Japan, to take advantage of the vinegar's purported deodorizing, antibacterial, and even therapeutic properties. Perhaps the most popular use is in foot sheets, where the bamboo vinegar is dried into a powder and added to patches, which are applied to the soles of the feet overnight.

Popular foot sheet brand Ashirira Sheet makes a whole line of the products, mixing the bamboo vinegar powder with other natural ingredients (including plants like lavender, mugwort, and grapefruit, or other materials like powdered titanium). Fans of Ashirira Sheet's bamboo vinegar foot sheets say that wearing them overnight on their feet can help them relax in the evening, sleep deeper, and then wake up feeling refreshed and restored.

Thanks to the lush bamboo forests in the Japanese countryside and the careful processing done by factories like this one in Kumamoto Prefecture, the countless organic compounds and minerals found within bamboo vinegar are undeniable, so it's easy to see why the liquid has long been popular for therapeutic uses. Will the Ashirira Sheet bamboo vinegar sheets really help you rest, relax, and recuperate? Well, there's only one way to find out, and that's to try them out yourself － they're easily available at drug stores in major cities around Japan (or online at the official website). Slap a few on your feet and let the natural bamboo vinegar sheets do their work, you might just find yourself a new fan of this unique Japanese ingredient.

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