杏吧原创

Wine鈥檚 complex flavour is the result of a delicate balance of fruity, floral, earthy, sweet and other aromas. Yet if one is too strong, it can ruin the overall taste. The solution? Magnets.

Cabernet Sauvignon and Sauvignon Blanc often contain a green bell pepper flavour that gives subtle character in moderation but tastes strange in excess. It鈥檚 most pungent in grapes that are picked early or grown in cool climates.

at the University of Adelaide, Australia and his colleagues found a way to remove excess bell pepper flavour from Cabernet Sauvignon by treating it with tiny magnetic beads.

The nanosized iron beads were coated in plastic molecules designed to attract the bell pepper-tasting chemical. The team stirred the beads through the wine for two hours to mop up the undesirable chemical, then sucked them out of the liquid using an ordinary magnet.

Chemical analysis revealed that the magnetic treatment removed 74 per cent of the green bell pepper flavour. A panel of eight blinded taste-testers confirmed that the treated wine no longer had the unpleasant aroma.

Still fruity

The beads partially removed some of the wine鈥檚 fruity chemicals as well, but the differences weren鈥檛 significant enough to be detected by the taste-testers. They rated the treated wine as having the same fruity character and overall aroma intensity as the original wine.

The magnetic treatment is a major improvement over existing methods for improving wine, says Jeffery. At the moment, winemakers typically blend batches with strong bell pepper notes with lighter ones to try to balance out the taste, or add activated charcoal or oak chips to remove the overpowering flavour. However, these additives tend to 鈥渞ip out lots of the other flavours as well鈥�, says Jeffery.

The magnetic approach could potentially be used to strip other undesirable chemicals from wine, which typically come from grape moulds, barrels, or smoke pollution, says Jeffery. The plastic molecules on the magnetic beads could be modified to specifically capture these chemicals, while leaving the rest of the flavours intact, he says.

Magnetic nanoparticles are also being used for a range of other purification purposes. For example, 聽at the University of Wollongong, Australia, and his colleagues recently showed that magnetic beads can be used to suck up oil spills. Other researchers are using magnetic beads to try to capture and remove .