The question: It has been suggested that I purchase unglazed clay goblets to "smooth out" the taste of some more economical reds. What is your opinion?
The answer: Ah, the old pottery-class trick. What you've been told is not entirely bizarre, but I can't recommend the practice.
The theory has basis in science as well as ancient wine-making convention. Certain red wines, such as cabernet sauvignon, are high in tannins, natural compounds found in grape skins and seeds. They provide flavour structure and also protect wine from the ravages of oxygen. But they can taste harshly astringent. Think of the dry sensation of strong black tea or walnuts, which also contain tannins. Certain forms of clay can bind with tannins and remove them from wine. Bentonite, a type of clay, is widely used in the so-called fining process to help clarify wine prior to bottling, stripping such particles as dead yeast cells, proteins and tannins that linger after fermentation. The particles clump together and drop down to the bottom of a barrel or tank, where they can be easily removed.
It's possible that pouring wine into an unglazed clay vessel would have an analogous effect. But if it occurs, the phenomenon would be subtle. That's because the goblet's inside surface has limited contact with the wine, and only for a short period (the time it takes you to drink up). Bentonite is added to wine barrels and tanks as a slurry – bentonite powder mixed with water. As it's stirred around, it mingles more thoroughly with the liquid. You'd have to pulverize a bunch of pottery and dump the powder in your goblet, then wait for it to settle at the bottom with the tannins to yield a comparable effect. You don't want to do that.
But there are people in the wine industry – let's call them mavericks – who may toast your ingenuity. There is a small but growing band of producers, mainly in Europe, who have been revisiting age-old practices, fermenting and in some cases aging wine in clay amphorae. They do this not so much to strip wine of tannin as simply to go against the modern grain and make wines that may offer some clue as to what stuff tasted like before technology got its hands on the business. One famous example is Josko Gravner in northeast Italy, but there are many others. It's possible that the clay, which is more porous than a steel tank, softens the wine simply through slow, controlled exposure to air. This is what happens in oak barrels (which are porous), but oak imparts its own strong flavour to a wine. Maturing a wine in clay rather than oak may deliver the softness of oak without the woody, vanilla-like flavour.
The problem with clay per se is that it can leach minerals into your wine, altering the flavour. Some people would describe the taste as earthy. So you'd still be stuck with a lot of tannin while messing with the natural flavour of the wine. You may find the resulting taste appealing, but I wouldn't sign up for a pottery class to make myself a new set of wine goblets – unless the teacher looked like Demi Moore in that scene from Ghost. Plus, you'd have to make more room in your cupboards next to your expensive wine glasses for all that crockery.
Have a wine question?
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.