You should rinse your glass with water between wines at a tasting.
Although it may be tempting to rinse your glass with water between wines when you are at a wine tasting, doing so is actually counterproductive. Even a little leftover water in the glass will dilute a wine, making it taste unbalanced and discombobulated. If you think the next wine will be influenced by the previous wine, the best bet is to rinse your glass with a few drops of the wine to come. Interestingly, in Italy they don’t consider a washed glass prepared to even receive wine until they (as I like to think of the ritual) “baptize” it with rinse wine, a process known as avvinare i bicchieri (ah-vee-NAH-reh ee bee-kee-AIR-reh). There is one big exception to the “rinsing with wine” idea. If a wine is flawed, it’s best to abandon that glass altogether and proceed with a new, fresh glass for the next wine.