The following is a classic science post I wrote for the coolass metablog in May 2004.
Sometime last week, Penta Water was introduced to our group. Not having any on hand, and only having vague second-hand assertions of “five-molecule water”, the usual response was “What, it’s just a very small quantity of water?” Based on the assumption that it was probably five-atom water (since that made slightly more sense to us), theories ranged from “Maybe it’s a liquid with a different molecular makeup but similar characteristics to H2O,” to “Maybe they count disassociated Na+ and Cl- ions from a tiny amount of salt in the water as two additional atoms,” to “Maybe it’s total bullshit.”
The key to unlocking this marketing mumbo jumbo is understanding water.
The past decade or so has seen a small group of physicists and chemists trying to answer some of the most fundamental, yet troubling, questions about what liquid water is. For example, no calculation or model has ever been able to explain exactly why water has such high surface tension. Similarly, no one knows why water can hold so much energy (i.e., why it’s specific heat is so large). These and more esoteric questions about water have led these scientists to try to model how water molecules interact.
Because of their strongly polar nature, water molecules seem to spontaneously form structures, and although usually these structures are random and tree-shaped, sometimes they are ringed. These rings are called isotopomers, and can take the form of tetramers (4), pentamers (5), hexamers (6), and even larger. It’s important to understand that all water forms these structures spontaneously and transiently (generally on the order of picoseconds).
From here, we go from hard science into marketron land. Penta claims that their water is so pure, so free of impurities, so well filtered, that the molecules in their water forms smaller water clusters. They then go on to say that smaller water clusters are more easily absorbed by the cells in your body, and thus that drinking their water is somehow more “efficient”.
I will allow the reader to draw their own conclusion as to the validity of these statements. Penta has links to research “supporting” their claims, but I am neither a physicist or a chemist. I would be unlikely to go any further than suggesting that Penta is probably no worse than any other filtered bottled water.