We like our wine to be dry, don’t we? Unless, of course, it is unashamedly very sweet (and even this, alas, is a minority taste). But the supposedly dry wines on our shelves can vary substantially in how much unfermented sugar they contain – and those that fall between dry and sweet present real challenges.

Sweetness in wine, known as “residual sugar” or RS, is usually measured in grams per litre of liquid, although Americans generally express it as a percentage. It is impossible to get RS levels down to zero (wine starts out as very sweet grape juice) but the general threshold of perception of sweetness is around 2g/l (or 0.2 per cent). Most fine red wine is well below this, often less than 1g/l, so doesn’t taste at all sweet.

It’s a different story with mass-market brands. Yellow Tail, the archetypal “critter” brand so successful it now accounts for almost half of all Australian wine imported into the US, is famously relatively sweet – as is one of the most successful brands of California Chardonnay, Kendall Jackson Vintner’s Reserve. These brands are likely to notch up sugar levels of at least 5-6g/l. Some of the California whites naughtily labelled Chablis, even though it is a controlled geographical appellation in Europe, can notch up well over 10g/l of sugar, often in the form of deliberately added sweet grape juice concentrate.