What Is Reverse Osmosis Filteration?

Why does bottled water taste so good? It's all about what's been removed (gross stuff) and added (clean and tasty stuff), beginning with a process called reverse osmosis. Many restaurants have reverse osmosis systems to provide diners with the cleanest, best-tasting water possible.

Long story short, the process involves separating the solutes (gross stuff) from the solvent (clean, unadulterated water). That's right, we're taking a trip back to tenth grade chemistry. Normally, a solvent will filter from a lower solute-concentrated solution to a higher solute-concentrated solution. That's regular osmosis. But reverse applies pressure to flip the process. Tap water is pressure-forced through a semiporous membrane, removing any molecules larger than the water itself: bacteria, pyrogens, viruses, pesticides...stuff you don't want swimming around in your glass. This technique is particularly useful when desalinating ocean water. It's more of a finishing process than a filtration system, known as "hyperfiltration." In addition to being perfect for drinking and cooking, some industrial processes involve RO to keep mineral deposits from building up on machinery. Useful!

The technology doesn't just apply to water — RO can be used to concentrate flavors by removing flavorful solids from liquids, protein from whey and helps speed-filter wine for increased production. Just don't tell your water sommelier you prefer your H2O pressure-pumped through a membrane — he's all about the balance of the naturally occurring minerals RO effectively removes and might yell at you.

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