What's That Black Thing in Your Water?

  • Holly Helt

To make most tea, it takes two things: leaves and water. While everyone goes on and on about the leaves, a lot of folks don’t give a second thought to the water they are using. Sure, you can grab some Brita filtered water and feel that is good enough, but if you want your tea to really sing, do what I do…

Not to make you green with envy, but my house in Kyushu pumps water from a natural spring 80 meters below! It’s such amazing water that I bottle it in 5 litre jugs and haul it to the café for use in all of our teas and even the dog’s water bowl.

But even so, I still put a piece of special white charcoal, called “sumi” in Japanese, in all of our jugs of natural spring water. I’ve been doing this for years, no matter where in the world I am. Sumi infuses your water with the right kind and amount of minerals and takes all the gunk out with a force unlike any other.

Let me make the distinction between Japanese sumi, take sumi (pronounced ta-keh) and binchotan or bincho. Sumi means “charcoal” as an overall term and there are many kinds of sumi. Take sumi is made of flat pieces of bamboo and not good for putting in water or in cooking. Better for sticking in stinky shoes! Binchotan, on the other hand, is baton-like and made with a special kind of oak called kashi ubame, found mainly in Wakayama, formerly Kishu, hence Kishu binchotan, (sort of like a brand name!). Wakayama, with ideal rain and wind, produces especially strong wood for sumi but it is found in a few other areas, though Kishu is famous for it. This area is also known for perfecting the firing technique.

Binchotan, and most sumi, is made by burning kashi branches slowly over high heat and then right before removing them from the kiln, the temperature is driven up to 1000°C until the wood pieces turn red hot. When these red hot puppies are removed, with the skill of a professional Jenga player, they are immediately cooled by being covered in a mixture of sand, ash and dirt which turns the red coal to white for a brief period, and why it’s often called white charcoal. The bark has been blasted away leaving a rock-hard black stick, each one uniquely shaped. Funnily enough, it’s jet black but if you look closely, you’ll see a white cast to it.

Japanese sumi is especially effective at purifying, softening, and mineralizing water through exposure to this absorbing natural element but credit really goes to the zillions of micro-pores it has. The type of wood and the way it’s made creates cavities for microorganisms to get to work breaking down all kinds of unhealthy matter in your water and do a super job at removing chlorine, taking the nasty smell with it. Chlorine wreaks havoc on your body, so imagine what it does to your tea!

When the water first makes contact with the piece of sumi, tiny bubbles appear on it. Wait about an hour so the sumi has a chance to work its magic. I know, this seems like a hassle, but just keep several jugs with sumi on the go, and top them up regularly, so you always have pure water at hand. I refill all of mine at night.

sorting the sumi

When you first get sumi, you need to activate it by simmering it for about 10 minutes in regular water, and then allowing it to dry naturally for up to two days. You will also need to clean and recharge in the same way every few weeks. One piece of sumi lasts between 3 to 4 months but with our clean Kyushu spring water, I have a couple pieces that are older than a year. Sometimes it will break in half – don’t worry, it’s still effective! You’ll know intuitively when to retire it, like when it starts to crumble, and then it’s best to put it in your flowerbed or garden plot.

Many commercial filtration systems use activated carbon, which is very similar. Sumi, however, has a much larger surface area and flat out does a better job. Just one gram of Japanese sumi has a surface area of anywhere between 300 to 2000 square metres (football pitch size!). Scientists can calculate this by looking at how the carbon dioxide gas in sumi changes at room temperature. The sumi I use is closer to 35 grams so just imagine what a powerhouse it truly is!

Sumi also deflects negative ions in your environment. Leave a tray of it around to clean your room, have it next to your computer to stop your body from buzzing, put them in your stinky shoes, they’re great for the loo, and pop a few in the tub for one incredible scrub-a-dub-dub! It works like magic to soften skin and give your hair that silky shine. My Japanese friend went a step further by putting a ton of take sumi under the flooring of her organic shop to clean the energy of her store!

And if all that isn’t enough…sumi is alkalizing to the tune of PH 8 – 8.5! That’s like having a green smoothie followed by a field of kale.


by Holly Helt

(This post was first published on the T-Ching blog)

About Holly Helt

Holly is American and grew up in Japan drinking Japanese tea from age-three. She has studied two methods of tea ceremony, Urasenke and the lesser-known Yabunouchi, which has a direct lineage to Sen-no Rikyu (known as the father of the tea ceremony) ; it's also the school of practice for samurai. In 2012 she founded Chiki Tea - an online retailer of Japanese green teas, all sourced directly from small farms in Japan. Splitting her time between Japan and her home in Texas, Holly strives to bring the best teas from Japan to as many people as she can find to share in her life's passion.

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