Chromatography is a broad range of testing methods which helps separate or analyze complicated mixtures. Malolactic Chromatography is a specific test used in winemaking which aids in determining the presence of malic acid and lactic acid, and hence gauge the stage of fermentation for a particular wine. It is both complex and simple. If you wish to know more, there is a wealth of information available on the Interwebs. Thanks Jennifer and Andrew of Eminence Road Farm Winery for drawing my attention to the accidental beauty of this test.