Here's the low-down on these mineral-rich hot drops, says Sam Wylie-Harris...

Minerality is a trendy word in the wine world. We're growing accustomed to tasting notes identifying a wine as having a 'streak of minerality', which is usually bookended with 'very pure' and 'lean'.

And certain wines - such as a Chablis or riesling - are typical examples, with their high acidity, which reflects a specific soil type.

But what about vines planted on volcanic soil? Somehow the word volcanic doesn't have quite the same ring to it as a Burgundy blonde or a racy riesling. Yet evidently, it should, because they're about to peak in popularity.

"It's true that vines grown on clay or limestone can be among the best in the world, but the mineral-rich nature of volcanic soils - which can be found in places from Santorini to Soave - means they're right up there in the rankings," says Steve Daniel, head of buying, Hallgarten, which was named European Merchant of the Year 2018 by the Sommelier Wine Awards.

Indeed, the role played by terroir (soil and climate) is the driving force behind these aromatic wines with a saline, mineral edge: "These vines grown on ancient soils really take terroir to the next level with their mineral characters, fresh acidity, salinity and distinct longevity," says Daniel.

Here are three volcanic whites Daniel has tasted and rated...

1. Santorini: Gaia Wines, 'Wild Ferment' Assyrtiko 2018 (£28.19, The Drink Shop)

One of the pioneers of the modern Greek wine revolution, Gaia Estate was established in 1994 by Greek winemakers Leon Karatsalos and Yiannis Paraskevopoulos.

"The soils here are porous and with a high mineral content," says Daniel, "which in turn, imparts a striking mineral quality to the resulting wine. Add to this long hours of sunshine, very little rainfall, sea mists and strong summer winds, and you really do have a unique microclimate.

"Plus, the surrounding Aegean Sea acts as a climate buffer, which softens the extremes and means minimal vintage variation. The vines are trained on a traditional basket-shaped system called 'kouloura'."

Tasting note: "A highly complex, aromatic and funky nose, with citrus notes combining with floral hints from the acacia wood, vanilla, toasty oak and a touch of smoke. The funky layers of wild ferment envelop this precise and dry wine, which has a mineral and salty complexity to the tangy finish. This is a truly unique wine." says Daniel.

2. Soave Classico: Ca'Rugate 'San Michele' 2017 (£12.64, Great Wines Direct)

A family business which has been handed down through the generations of the Tessari family since the early 1900s, the estate was renamed Ca'Rugate in 1986 and takes its name from the volcanic hills where the vineyards are located.

"The estate is now run by the fourth generation Michele Tessari and he brings a brilliantly lively, passionate and entrepreneurial spirit to the company," explains Daniel. "He's recognised what makes his wines stand out is the fact they come from a hillside vineyard in Monteforte d'Alpone within Soave Classico - the soil here is purely clay and basalt, and to maximise the flavours, he limits yield to 125 quintals per hectare."

Tasting note: "Elegant floral aromas combine with notes of fruit and a touch of peppery spice. Crisp and zesty on the palate, this elegant wine shows notes of sweet almond on the finish."

3. Yamanashi: Grace Winery, Koshu Kayagatake 2017 (£17, Novel Wines)

"Volcanic soils also stretch to Japan," says Daniel, "and here we have one from the Grace Winery, established in 1923 in the Katsunuma province - the birthplace of the Japanese wine industry."

This white is made from Japan's most important indigenous grape variety (koshu), with fruit grown on distinctively volcanic soils with good drainage. "This particular vineyard has a cooler aspect, allowing the slow maturation of the grapes over a long growing season," explains Daniel.

"Traditional trellis pruning has been cast aside in favour of a modern long cordon training system, which helps to control yields, concentrating flavours and sugars, to balance the high acidity that occurs naturally in this variety. The grapes were hand-harvested at optimum maturity."

Tasting note: "Light and floral in style, the freshness and elegance of this wine is quite remarkable. Delicate flavours of lemon, lime, green apple and grassy notes are backed by a thirst-quenching acidity, delicious peppered spice nuances and minerality on the finish."