With wine tasting season looking like it might actually happen this year, and tasting room visits definitely on, I was reminded yesterday that it's still a thing for people to rinse their glasses with water between tastes of wine. Here's a thread on why you really shouldn't. 1/

A few years ago, we did an experiment in our lab to measure the impact of water residue in a glass. We mimicked what we typically see at tastings: where a taster pours water into a glass, swirls it around a bit, and then dumps it, holding it upside down for a couple seconds. 2/

Then, we measured the difference in the wine's alcohol with and without the water. With a one-ounce pour, we found the water dilutes a 13.5% wine to 12.6%, a reduction of 6.9%, because to your ounce (29.6 ml) of wine you've added 2.1 ml of water, thinning texture and flavors. 3/

Calculated another way, we would get the same effect by pouring ~11 gallons of water into each ton of grapes. This this impacts both the taste and the texture, thinning out a wine and shortening its finish. This is true even with distilled water, which is free of impurities. 4/

Using mineral water, filtered water, or tap water can have even more unpredictable effects. We tried the same experiment with filtered water and found that the water's mineral content reduced the amount of malic acid in our sample from 0.21 grams/liter to 0.08 grams/liter. 5/

These sorts of interactions happen because the dissolved basic compounds in mineral-rich water bond with the acids in the wine, with unpredictable results. I've even seen people rinse with chlorinated water. I can't imagine that wine tasting remotely like it was intended. 6/

So, what should you do at a wine tasting? Don't feel that you need to rinse at all, unless you're trying to eliminate a strong flavor, or you're moving from red to white. Remember, most wine is chemically structured more like almost any other wine than it is like water. 7/

Put another way, the little bit of Chardonnay you have in your glass is going to impact your next taste of Syrah much less than an equivalent amount of water would. Even better is to rinse your glass out with a little of the wine that you'll be putting into it next. 8/

It doesn't take much, and the winery representative who's pouring the wine will likely be pleased that you care enough to taste the wine properly. I know I always am. This is particularly important at big tastings, where you often go from tasting white to red and back again. 9/

But in a normal dining or tasting room environment, just remember that you're usually fine just moving from one wine to the next, using the same glass. And that if you do rinse, you need to be sure to empty and dry the glass as best you can. Happy tasting! 10 & END/