Adjectives are often physically based: Stephen King is a master of spine-tingling terror while the late Grande Roche chef Frank Zlomke made a mouth-wateringly good cappuccino of foie gras. Just the thought of a tasty treat is enough to get the saliva glands pumping and everything we eat or drink is helped on its way down the alimentary canal by a generous helping of dribble, drool, gob, slaver, spit, spittle or sputum. Which casts a new light on the old debate about the merits of single varietal wines versus blends, for every wine is tasted as a mixture of fermented grape juice with “a thick, colourless, opalescent fluid that is constantly present in the mouth of humans and other vertebrates“ aka saliva. Men drink a couple of litres of the stuff a day while women, according to Psychology Today, get by on half that amount. Which could explain why the weaker sex is famously better tasters than men – they drink their wine in a less dilute form.

Encyclopedia Britannica informs us that saliva is composed of “water, mucus, proteins, mineral salts, and amylase” the last named an enzyme that starts off the process of digestion and also helps swallowing. Spit is an important factor in tasting wine for a variety of reasons: it contains both sodium and potassium chloride that has a buffering effect on flavour; it neutralizes excessively acidic wine through dilution and alkaline buffering. In fact one way of assessing the acid levels of a wine is to judge the amount of saliva generated; saliva also breaks down chemical compounds, thereby developing secondary flavours. So all that pretentious savouring of wine in the mouth while emitting low frequency grunts of contentment that you encounter at John Woodward’s Joburg Wine Show, is not pure posing, there is a physiological explanation, too.

One simple experiment to gauge the effect of saliva on wine is to pour two measures of a tannic red (anything from the 2006 vintage will do) into two glasses. Swill the first glass around your mouth and return the contents to the glass. Let both glasses stand for five minutes and re-taste. The rinsed wine will taste magically softer and more approachable.

The saliva production difference between the sexes is an important one, as having less saliva makes women more sensitive to sourness, bitterness and astringency which makes a male assessment of a particularly astringent Pinotage problematic for women and visa versa. In fact Jan Boland Coetzee made his Entopio Pinotage blend especially soft to appeal to the fairer sex who often find the varietal too bitter. That said, it’s surprising to note that some of its biggest fans are women: the Pinotage Trophy at the Michelangelo International Wine Awards is sponsored by Australian judge with an Afrikaans name, Sue van Wyk, while another Australian émigré, Marietjie Brown, completed a thesis on the “moods of Pinotage” for her Cape Wine Master diploma.

Not only are there sex differences in saliva production, but spit levels differ between individuals with, on the evidence of his foam flecked lips, heart pioneer the late Chris Barnard among the champions. Soccer and rugby players seem to be especially well endowed in the sputum department judging by the amount of spitting captured by TV cameras while spitting in China is a national hobby. When fatigued or under stress, we produce less spit while the pH of our bodies also varies constantly, with higher body acidity coinciding with greater organoleptic sensitivity. To a “low flow” salivator (or even a “high flow” approaching the end of a line-up of 145 Cabernets at a wine tasting) wines will taste more astringent, purely as a result of low volumes of saliva.

The perception of tannins (from both grapes and oak the wine may have been matured in) is actually one of touch as tannins coagulate proteins in saliva, creating a perception of puckering or a sensation of drying. In extreme cases, cheeks and tongue adhere to the teeth, while the dents themselves feel like they’re wearing woolen jumpers. Fatty foods, such as cheese, coat the mouth and prevent saliva from bonding with tannin and so make harsh wines easier to swallow, thereby explaining the tradition of serving blue cheese with Port.

Saliva is largely responsible for the mouth-feel of a wine. When we say a wine tastes “velvety” or “silky” we are reacting to the long chains of molecules caused by the proteins in the saliva reacting with tannins in the wine. The shape and nature of these “stringy bits” of spit you can see in any spittoon is responsible for the perception of a wine as “furry” or “grainy” while a “chewy” or “grippy” wine is one whose astringency has caused a tactile response in its reaction to saliva.

Spitting is the last of the five s’s in wine appreciation – after seeing, swirling, sniffing and slurping – and is a vital activity if objectivity is to be maintained. Accurate spitting is a sine qua non for the professional wine taster with splash-back from overfull spittoons an occupational hazard. A facility with spitting is what separates wine tasters from whisky, brandy and beer pundits, who don’t. Spitting certainly explains variations in girth between the two groups, although it does not explain the fondness of beer tasters for beards, especially among males.

Saliva is also important in protecting the teeth of wine aficionados as it forms a glycoprotein layer and buffers those enamel-eating acids present in wine – and what a sour line up they are: tartaric, salic, lactic, malic, acetic… a bit like the juice in a jar of Judy’s Extra Strong pickled onions (the best ones). The action of swishing wine liberally around the mouth and then expectorating makes sure that the teeth get maximum exposure to wine acids, so the American Academy of General Dentistry recommends tasting wine through a straw – which must be why appearance conscious female hip-hop superstars enjoy their Cristal champagne through a “bendy straw.”