If you pay strict attention to the wines you buy, you may notice that there often are slight differences between two bottles of the “same” wine. This phenomenon is called “bottle variation.” Wine makers know it’s a hard-to-avoid pitfall. In particular, with wines made in the millions of cases, variations can be great. A 10,000-gallon tank can hold only about 4,000 cases of wine, and some wines that are made in the millions of cases because of logistical reasons often are made up of different lots that have different flavors. But I’ve heard nothing from consumers about bottle variation that may exist in any large-volume wines, because the typical buyer of such $1.99 to $4.99 wines isn’t concerned about bottle variation. Bottle variation can occur also in tiny wineries where an entire bottling can be done from a single tank of wine—where you would think bottle variation simply cannot exist. …