White chocolate is technically not real chocolate as it doesn't contain any cocoa solids, but it is made primarily of cocoa butter, sugar and milk solids. White chocolate must contain at least 14% milk solids, including 3.5% milk fat. It retains a popularity all of its own as a vanilla-scented indulgence or as a decorative contrast to dark chocolates.
Better brands of white chocolate are made with a high proportion of cocoa butter and real vanilla. Avoid anything with vanillin.
Keep white chocolate in a cool, dry place for about six months (it will still taste okay after this time, but will not melt as well if kept any longer).