#223: Optical juice-ometer

It’s sometimes difficult to make up squash drinks whilst avoiding over-concentrating them. Even the ones without unpleasant additives (ie 16 spoonfuls of sugar per 500 ml) are probably not good for you, if served in too concentrated a form.

Today’s invention provides a way to ensure that the drink is correctly diluted, irrespective of the geometry of the glass used, or the volume of drink prepared (and without having to use a range of traditional glass hydrometers).


A section of the plastic label on each bottle consists of strips, separable from each other using perforated seams. There are enough strips to allow one to be used per serving from the bottle. Each strip has one half of its length printed white and the other half printed with the colour variation with depth of that particular juice when correctly diluted.

To make a drink, pour an amount of concentrate into a glass. Tear off a strip from the label and bend it, at the division between white and coloured regions, to the angle shown on the label. Drop the strip into the liquid so that the coloured section lies on the liquid surface and the white part lies submerged in the drink at the specified angle.

Add water gradually, whilst looking into the glass from above. When the strip appears perfectly symmetrical (ie the variation in drink colour above the white, underwater, angled end matches the colour variation printed on the end held on the surface), then the dilution is correct.

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