At this time, usually in March, rather than rack the different lots of new wine from barrel to barrel, the wines are brought to tanks where a blend is made. The wine is thoroughly mixed and then brought from the tank back to barrel. Sometimes the winemaker is unsure of how a wine or a group of wines will age, and he may question how they might fit into the blend. In such a case, he may make a second blend fraction which is held separately during aging for observation. He may at a later date reconsider the final bottling blend for inclusion of this separate lot.