It is well known that your perception of a wine is affected by the wine you tasted immediately beforehand. This is similar to how other senses behave. If, for example, you sit in the dark for several minutes and then expose yourself to normal daylight, it seems to be exceptionally bright until your eyes adjust. With wine, if the previous wine was flabby, your current wine will tend to taste sharp; if it is was very dry, then sweet, etc.
However, in addition to that effect, the order in which you taste wines can help determine how much you like them. I have already written about Antonia Mantonakis’ research, where she presented sequences of wines to consumers, and asked which wine they liked best. In actual fact the same wine was offered in each glass, but the tasters still expressed a preference. For shorter sequences (2 or 3 glasses) they tended to prefer the first wine tasted, while for longer sequences (say 5 glasses) they preferred the last one. If you are thinking “that just goes to show how little the average consumer knows about wine”, you should be chastened by the fact that those with better wine knowledge were even more prone to this bias. But how much practical significance does it have? The consumers were after all asked to distinguish between identical wines, and they may have thought any differences were very small.
Later work by French researchers throws more light on this order effect. Here the experiments were performed on wine professionals tasting in competitions that awarded medals to Beaujolais Nouveau wines. Here, in each of two competitions of around 400 wines, approximately 100 tasters scored wines on the 100 point scale, each taster being given two flights of between 10 and 12 wines. But into each tasting sequence of wines registered in the competition, the experimenters put the same (unregistered) wine into the first and penultimate positions. For each competition, the average score for the penultimate wine in the sequence was greater than that for the first wine: 82.99 vs 79.78 for one competition, and 83.93 vs 81.78 for the other. Those differences are not only statistically significant, but also significant from a practical point of view. To get some feel for the practical significance, note that the difference between a silver and gold medal winning scores is 6 points. Also, as the required score to achieve a silver medal was 81, in one of the competitions the position of the wine would have affected the colour of the medal awarded .
If wine scores are important to, then you should probably be concerned about the sequencing used in tasting flights. On the other hand, if you do not pay much attention to scores, you can now add order effects to the list of reasons that justify your position.
 Carole Honoré-Chedozeau, Jordi Ballester, Bertrand Chatelet and Valérie Lempereur, “Wine competition: from between-juries consistency to sensory perception of consumers”, BIO Web of Conferences 5, 03009 (2015)