Oh no! Magnets and wine are back in the news (see here, here and here). The gizmo under discussion is marketed by Dr Patrick Farrell MW.
Dear readers, unless what we know about science is false, I reckon there is as much chance of this device doing what its manufacturers claim as there is of Stuart Pearce phoning me up and asking me to play centre forward for Manchester City in their opening game of the season against Chelsea. Tannins are not going to undergo chemical rearrangement into longer chains as a result of a magnetic force. The reason people have been convinced this device 'works' is that it is aerating the wine. Pour the first glass and taste it. Then pour a second through this device, and it may well taste a little different because it has been aerated. The proper comparison is to take the device and compare it with one which is the same, just without the magnets. Pour a glass from each, but under blind conditions so the power of suggestion is removed. Any difference? I didn't think so.