Black and Blum Eau Good Duo water bottle
Review

Hands-on review: Eau Good Duo water bottle

Get that clean mineral water taste from just tap water with the filtering power of charcoal in the Eau Good Duo water bottle.

We all know we should drink more water. Most office workplaces offer water coolers or dispensers and while these go some way to addressing our refreshment needs, the source of the water, the piping it’s fed through and the state of the dispensing tap all too often conspire to present an unpalatable proposition.

What is the solution? Buy bottled mineral water? Perpetuate the plastic pollution of the planet, given that there are an estimated 22 billion plastic bottles discarded each year? With the best will in the world, inevitably we all fail to recycle every bottle we buy.

Here’s one alternative: the charcoal-filter Eau Good Duo water bottle. Duo, because as well as filtering tap water, the bottle can also double as a fruit infuser, if that’s your hydrating bag. You just have to remove the charcoal stick first: purify your water, take the stick out and bung in your fruit concoction of choice. Away you go, swigging possibly the freshest free water you’ve ever drunk.

The Eau Good Duo is the latest product from Black+Blum, a London design firm based in the Oxo Tower. The company has created a range of portable, lunchable solutions with a modern, minimalist aesthetic. These 700ml Eau Good bottles are part of the Box Appetit range of products, all clean lines and environmentally friendly materials.

The Eau Good Duo Kickstarter campaign officially began this week, but we’ve been using a pre-release version of the Eau Good Duo for a few weeks now (we also previously road-tested its Box Appetit cousin, the Eau Good Filter water bottle, which features the same design and charcoal stick, only with a simpler cork stopper, sans infuser) and there is no question that these bottles vastly improve the taste of tap water.

The key is the binchotan charcoal stick, an active carbon made from tree branches and renowned for its ability to soften water, add good minerals, balance the pH and absorb unwanted tastes and odours, such as chlorine.

This charcoal has been used in Japan as a water purifying solution since at least the 17th century, so it comes with good provenance.  Binchotan charcoal has an incredibly porous surface, with tiny cavities oriented in many directions. The ions of contaminants are attracted to the surface of the carbon, where they are held in place, while good minerals such as calcium, iron and magnesium are released back into the water thus enhancing the taste.

The Eau Good Duo bottle (made of BPA-free tough plastic) is shaped to fit the binchotan sticks and Black+Blum states that one stick should last approximately three months with daily use. It can then be ‘recharged’ by boiling it for ten minutes and leaving it to dry naturally (i.e. not on a radiator). It should then give another three months of filtering life. The company also offer automatic e-mail updates, to alert you when it’s time to boil and/or replace the charcoal stick. Replacement sticks cost around £6.99.  

When a stick has reached the end of its useful life, it can be broken up and used to add nutrients to the soil of your potted plants and even used as a deodoriser to remove unwanted odors in your cat litter, laundry basket or shoes, due to its porous surface. It is also an effective moisture absorbent and can help absorb humidity in small spaces.

It also doesn’t matter if tiny fragments break off the stick over time and you happen to drink them: it turns out that active charcoal tablets are prescribed to treat diarrhoea, digestion and flatulence. Quite the wonder material, all told.

So, binchotan charcoal is the star of the Eau Good show, although naturally (no pun intended) filtering water takes time. This is not an instant solution. You can’t just fill up the bottle, oscillate it gently and expect the charcoal stick to magically suck out all the bad chemicals. Clean water takes time, grasshopper. If you can leave it for one hour, tap water will taste noticeably improved. Several hours is even better and if you can get into a regime of refilling the bottle the night before, by morning you’ll have fancy-pants expensive bottled water levels of delicious water purity.

This is the minor caveat with the Eau Good Duo bottle: you have to be disciplined in using it, cleaning it and updating your charcoal stick. There is more commitment here than just filling up a bottle from the tap and drinking it straight away, but if the taste of tap water is what is currently dissuading you from drinking it more regularly, this little extra effort is well worth it.

Aside from the water filtering aspect of Eau Good Duo, the bottle does double duty as a fruit infuser, as previously mentioned. The special built-in infuser cap keeps your vegetation at bay while you drink, with the cap’s thread cleverly placed on the inside of the bottle so that it feels more like drinking from a glass than a screw-cap bottle. The spout is also leak-proof and was engineered to allow a generous but steady flow of water. Finally, the ergonomically styled, dishwasher-safe bottle has a dual silicone strap and soft-touch finger loop for ease of holding and carrying when walking, running, cycling and so forth.

Announcing the Kickstarter campaign, Dan Black, co-founder and lead designer at Black+Blum, said, “Mainstream consumers are wanting sustainable solutions to help them get their daily intake of water without continuing to pollute our planet and oceans with plastic bottles. Our bottle allows tap water to become filtered or infused and taste great, all whilst helping people drink on the go, meaning it is great for active lifestyles.

“The Eau Good Duo will save consumers over £200 per year by reducing the need to buy bottled water. We can't wait to share it with the Kickstarter community and work together to bring this unique product to market.”

You can pre-order the Eau Good Duo Water Bottle on Kickstarter now, prices start at £24.00.

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