Viognier is quite a well known grape, now planted widely round the world but – that said – compared to (say) Sauvignon Blanc only about an eighth as much is produced. Fifty years ago there were only 34 acres in the world, planted in the Northern Rhone… now there are a thousand times that.

The upsurge in planting is partly due to technical advances in warding off problems with Viognier – susceptibility to mildew and the difficulty of determining when to pick – too soon and lacking in character, too late and lacking in acidity. It is mainly due to the attraction of the grape, at its best a hedonistic scent of floral and apricot notes, and a rich palate with (hopefully) a line of acidity and minerality to prop it up.

The floral notes are said to be produced by compounds called “terpenes”, which – unsurprisingly – are found in Riesling and Muscat too. As well as distinctive apricot notes, peach, greengage, honeysuckle and, if you’re lucky, citrus can be found.

The world Viognier vineyards are about equally split between France, Australia and the rest of the world. This last third dominated by the Anglo-phone countries of USA, S. Africa and New Zealand, the only other significant plantings being in Argentina.

The home of Viognier is the Northern Rhone, specifically the famous appellation of Condrieu, on the West bank of the Rhone just 40km south of Lyon: South of Côte Rôtie, but North of the other Northern Rhone Syrah Appellations: St. Joseph; Hermitage; Cornas and Crozes-Hermitage. In Condrieu the soil is granite-based and contributes a leaner, sharper structure to the wine.

This granite-soil and the Rhone’s local wind, the mistral, are good for Viognier’s need for dry hot climates without over-cooking grapes that can be low in acidity anyway.

In most of the rest of the Rhone, Viognier is blended with other white grapes: Marsanne, Roussanne, Clairette, or Bourboulenc, as well as Grenache Blanc, Maccabeo and Vermentino, also known as Rolle.

More Viognier is planted in Languedoc than in the Rhone now, and you are more likely to find either cheap blends (even with Chardonnay, Chenin or Muscat) or varietal wines, than in the Southern Rhone.

Really, away from the standard-setting area of Condrieu, the problem for production of Viognier is the grape’s tendency to be low in acidity. This is a typical new-world wine problem, and in the case of Viognier, Languedoc can be included in that classification. Cool climate production isn’t easy – the grape needs a long, warm growing season – so granite soil to build up minerality is a good strategy.

In the actual New World most Viognier is varietal, and handled a bit like Gewurztraminer, another opulent grape that has a danger of too low acidity. Argentina, by virtue of altitude, Chile or New Zealand seem more promising than other sources. Another New World factor, considering that the maximum age of vines there is likely to be 30 years, is that Viognier vines don’t really come into their own until they are 15 or older and some Condrieu vineyards (these must be those that still existed in the 1960s) have 70 year old vines!!!

Another factor for Viognier is its presence in Côte Rôtie, blended with Syrah to add perfume and stabilise colour. 5% Viognier is common in Côte Rôtie, although as much as 20% is permitted. It is not allowed in the other Northern Rhone Syrah AOC. However the Côte Rôtie formula is much copied in the New World, principally in Australia – but also memorably in the South African “Goat Roti”, produced by Fairview with 4% Viognier.

The actual title of this Tasting is “Viognier Blends”, but I thought we had to start with a 100% pure Viognier as a reference, and that has to be a Condrieu. Rather a modest one given the £40+ price tag that adheres to the top examples. After that we will try 5 blends, in a multi-grape package and then with Chardonnay, Marsanne and Rousanne.

The things to look out for are the relative acidity balance and whether the Viognier swamps, or is swamped by, its partner. Marsanne can be cloying too, for example, and Rousanne can be delicate.

Finally we’ll come to an example of Syrah / Viognier blending. There are dozens to choose from (including the Goat Roti mentioned above) but many are at the 5% Viognier level, and this is one I found with 15%, enough to see the impact of the grape as more than just a “seasoning”.