My wife claims the first sip of a wine doesn’t always taste the same as the second. Can this be the case?

The question

My wife claims that sometimes the first sip of a wine does not taste the same as the second. Is there something in the taste buds that needs to be activated before getting the REAL taste of a wine?

The answer

I concur with your wife and salute her for identifying an important, underappreciated truth. The crux lies not so much in the taste buds as on things commonly found on or around them.

One such thing is saliva, which plays a critical role in taste perception by modifying food and wine molecules and essentially delivering flavours to the taste buds. Wine gets salivary juices flowing, so it stands to reason that the second or third or fourth sip will be different from the first. For one thing, proteins in saliva can reduce bitterness as well as the astringent mouth feel of certain wines. That tannin-rich cabernet, for example, is likely to taste more pleasant as you work your way through a glass.

There may be other things on your tongue as well, such as residue from toothpaste or juices from food you sampled prior to the wine. If the food was particularly acidic, it may cause the wine – perhaps paradoxically – to taste less acidic. Rather than exacerbating the tart sensation, acid in your mouth tends to cancel out the acidity in wine, making it taste vaguely sweeter.

I'm often amused at how even the most ardent wine enthusiasts will ignore the huge role that food plays in modifying wine flavours. I can't count the number of times people have commented to me that a wine had "opened up" and improved over the course of a meal since the first (and often foodless) sip. There is a widespread tendency to attribute changes in perceived flavour entirely to a wine's contact with air over time rather than to chemical changes in the mouth. Proud wine snobs that some of us are, we want to believe that our palates are precision instruments and that, if we're tasting something differently over the course of an evening, it must be because the wine has changed, not because our mouths or moods have changed.

Some wine tasters are well aware of this, of course. That's why often experts in wine-tasting competitions will insist on a so-called rinse bouche (a mouth rinse) of, say, a crisp white wine to get the juices flowing and erase any extraneous food or toothpaste residues before moving on to the serious business of judging.

But even in such circumstances it's important to be aware that the wine you sip first can affect how the second wine tastes.

They key is, never rush to judgment. Take a sip, then wait and sip again before you pronounce a wine lousy or lovely. And, of course, always listen to your wife.

The Flavour Principle by Lucy Waverman and Beppi Crosariol (HarperCollins) won the top prize for best general English cookbook at the 2014 Taste Canada Food Writing Awards.

E-mail your wine and spirits questions to Beppi Crosariol. Look for answers to select questions to appear in the Wine & Spirits newsletter and on The Globe and Mail website.