Can An Eco Bottle Cap Change Your Bottled Water Habits?

Earlier this year we got wind of London-based design firm Plus Minus Design’s Solar Pebble, an innovative and simple device bringing eco-friendly lighting to rural Africa as well as urban settings. It generated a lot of interest from readers and resulted in a follow up interview with the designers to learn more about their work. We are therefore more than happy to do yet another follow up with them, showcasing one of their latest designs: Just Add Water.

Just Add Water, as described by Plus Minus Design technology director Tom Eales, is a design response “to the environmental issues surrounding bottled drinking water.” It adds what they feel is “an incremental step towards a more sustainable drinking culture,” which is a necessity when you consider that in the United Kingdom alone 3 billion bottles of water are consumed annually, with 80% of these being sent to landfill.

Just Add Water

image via Plus Minus Design

The product is described as allowing consumers to “buy bottle caps that deliver flavor, energy or vitamins to tap water. The sports cap has the ability to seal onto almost all plastic water bottles currently on the market through an intuitive push and twist action that mimics traditional screw fit tops. Added value is delivered through a gelatin-based liquid tab within the cap that dissolves rapidly on contact with water.”

This bottle cap, according to Eales, is still in the design phase, with more research being needed “into the gelatin based delivery system than there is currently to ensure that it is suitable for all.” If all goes well, this could perhaps see a launch date of next summer, depending upon potential interest “for either funding to drive the project further forward or to license the design to a third party.”

Just Add Water

image via Plus Minus Design

So what do people think – should Plus Minus Design push forward with this project? They say that “at Plus Minus we’re very passionate about this product and the benefits that it has the potential to bring to not only the bottled water but the entire bottled drinks industry.” Put your comments below.

I am the editor-in-chief and founder for EarthTechling. This site is my desire to bring the world of green technology to consumers in a timely and informative matter. Prior to this my previous ventures have included a strong freelance writing career and time spent at Silicon Valley start ups.


  • Reply June 17, 2010


    Thats a great idea, I love the concept and it has so many potential applications. I cant believe its taken this long for someone to really address the problems with bottled water rather then just offering gimmick solutions.

  • Reply June 17, 2010

    Thomas Eales

    Hi Guys,

    Just to add a bit more information to the description above;

    In terms of reusability, the bottle caps would be resable again and again. The only part that needs replacing is the gelatin flavor tab that delivers the added value to the tap water.

    Once you have fitted one of the caps to a bottle the top section (the green part) can tighten creating a seal so no drink is lost, or unscrew to allow users to insert new gelatin tablets. We would propose that replacement packs of these “flavor tabs” be sold alongside the bottle top itself, these can be seen in the image with 4 boxes in it and would be available in a range of flavors, perhaps including, fruit flavorings, energy or carbonation.

    Through this innovative way of adding value to tap water, what is perhaps an unattractive drink to some can be turned in to something else, it’s not quite “water in to wine”, but does bring significant environmental savings.
    The ability as mentioned to add value to tap water sets the product to be licensed very easily to leading brands;
    Lucozade/Gatoraid energy tablets, Ribena juice flavorings, etc.

    In terms of just which bottle it can fit on to, the product has been designed to fit any bottle with a screw-top cap, if there are bottles that it doesn’t fit (in the American market perhaps) that we were not aware of whilst designing the product then it would be a simple task to redesign the product accordingly. For sports bottle with very wide mouths it would be hard to make this product suitable, however thats not to stop people with those bottles just buying the flavor tabs in order to add value to their tap water.

    At the products end-of-life it would of course be recyclable in the same manner that plastic bottles are now.

    For more information about the product and where we see it going, either reply here, or check out the Facebook page where there’s more information about this product and others we are working on too:


  • Reply June 17, 2010

    Marie M

    I wish we didn’t have to wait until next summer to see these on the market. I agree that it’s about time that someone made some strides with bottle lids.

  • Reply June 22, 2010


    So, one would still have to buy bottled water to use this product? Can this product function independently of the bottled-water industry? I don’t see how different this is from packets with powdered drink mix, except for the added plastic of the cap. Many people do not want to reuse a bottle for fear of plastic chemicals leaching into the beverage after single use. Is this really an “eco” product? Perhaps if the cap filtered tap water to create a better flavor, rather than adding flavor to cover up what most people dislike about tap water. Perhaps the gelatin flavor tab is the real innovation.

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