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black+blum Binchotan Charcoal Water Filter & Locking Coil


It may seem counter intuitive to purify your drinking water with a stick of charcoal, but the Japanese have been doing it for centuries - and it makes your tap water taste great. No excuse for buying plastic bottled water if you don't like the taste of tap!

New feature: the addition of a locking coil to the filter allows you to use it in your on-the-go water bottle without it rattling around. The locking coil bends to fit your bottle ensuring the charcoal water filter is held in-place. The loop on the top of the coil helps you to remove the filter when the bottle needs washing.

Note: water filter with the locking coil requires a minimum spout width of 30mm

More on the Charcoal water filter: it adds minerals (such as calcium) and removes chemicals (such as chlorine). You can pop it into any water bottle, jug or other holder you have and it lasts for 6 months! Incredible stuff - read more about it below.

When you have finished using your binchotan as a water filter, it still has many secondary uses. If you break it up and put it in your house plants, it will add nutrients to the soil that will help the plant to grow. Due to its porous surface, it can be used as a deodoriser to remove unwanted odors in your cat litter, laundry basket, nappy bin or shoes. Binchotan is also an effective moisture absorbent and can help absorb humidity in the air if placed in a wardrobe. 

This is 1 vacuum wrapped binchotan active charcoal filter with a locking coil in a recycled card box.


  • 100% natural wood
  • Makes tap water taste great
  • Each filter lasts up to 6 months (with a recharge by boiling after 3 months - see below)
  • Stainless steel coil locks the charcoal into place and leaves no taste and won't rust your bottle
  • Pre-washed and ready to use
  • Fits in any water bottle or jug with a spout width greater than 30mm
  • Help the planet by not buying bottled water
  • Save money by avoiding bottled water

Size: (water filter) 11.8cm high, 2.5cm wide approx

Do not wash with soap.

What is the history of Binchotan charcoal?

The origins are not completely clear but it is believed that a form of Binchotan charcoal (sometimes referred to as 'white charcoal') was introduced to Japan by a Japanese monk and scholar called Kukai 1,200 years ago. It was during the Edo Period (17th century) that a man called Binchuya Chozaemon made it popular.

How is it made?
Sustainably sourced wood is placed in a kiln and charred at a relatively low temperature for some time, then, near the end of the process, the kiln temperature is raised to about 1000 degree Celsius to make the wood red-hot. The charcoal is then removed and quickly covered with a special powder made from earth, sand and ash, and this gives the charcoal surface a whitish hue (explaining the name 'white charcoal'). The rapid rise in temperature, followed by a rapid cooling, incinerates the bark and leaves a smooth, hard surface. If you strike it, you'll hear a clear, metallic sound.

How does it work?
Binchotan charcoal has an incredibly porous surface with tiny cavities oriented in many directions. Just 1 gram has a surface area in excess of 500 m2 (about one tenth the size of a football field). It is also known as active carbon as the ions of contaminants are attracted to the surface of the carbon, where they will be held. It is also able to release minerals such as calcium, iron and magnesium back into the water which enhances its taste and health benefits. 

How long will it last?
If you are using your Binchotan with an average water bottle (750ml) and fill it up once a day, then it should last three months. You are then able to recharge it by boiling it in water for ten minutes and then leaving to dry in sunlight. You should be able use it for a further three months. We recommend changing your filter every 6 months.

Do I need to wash my charcoal?
Your binchotan charcoal is already washed and ready to use. Please do not wash with detergent or soap.

Can I use my binchotan with flavoured water (fruit infused or tea)?
Please do not use with flavoured cordials, fruit infusions or tea.

Is it dangerous if I swallow a bit of charcoal?
Occasionally you will notice tiny particles/fragments of the charcoal in the water, but do not be alarmed as it will do you no harm if you swallow them (active charcoal tablets are prescribed to treat diarrhoea, digestion and flatulence).

If my charcoal is/arrives broken, can I still use it?
Due to the fact that the stick is an organic element, it is possible that the charcoal breaks (inside the vacuumed pack). The broken charcoal will still perform its job perfectly well, and will filter your water the same way the long stick would have done.




Dan Black and Martin Blum met while studying industrial design at Northumbria University. In 1998, not long after graduating, they formed black+blum.

With rigorous attention to detail and a focus on re-use and sustainability, they design original products that inspire a sense of wellbeing. 

They have won over 25 international design awards and many of our their designs are in permanent collections of internationally renowned design museums. 

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