Moscato d’Asti soil types are part of what makes the wines so distinctive.
Like nearly every set of official appellation regulations in Italy, the specifications for Moscato d’Asti DOCG begin with the same bureaucratic language (translation mine):
“The environmental and farming conditions for vineyards [used for the production of Moscato d’Asti] must be the same as those traditionally found in the area. And they must be capable of imparting to the grapes and resulting wines the distinct characteristics and qualities set forth in the following [appellation] specifications.”
But here’s where it gets interesting.
The first two rules, both of which immediately follow the perfunctory preamble, go right to the heart of what makes Moscato d’Asti stand apart from the sea of sparkling wine produced in Italy and the world today.
“1.1 Position: Hillsides with calcareous-clay [marl] soils. Vineyards planted on heavy or deep soils or on outcrops of sulfurous gypsum are not to be considered suitable. The minimum altitude is 165 meters above sea level.”
“1.2 Exposure: [Vineyards must be planted on] sunny hilltops and slopes. The valley floor is to be excluded as are shady parcels, flat-lying parcels, and humid parcels.”
From antiquity through the modern and contemporary eras, Moscato d’Asti has been considered a wine associated with a place — a “terroir-driven wine,” to use today’s winespeak.
“According to star producers,” writes Dr. Ian D’Agata in Native Wine Grapes of Italy (the most authoritative Italian ampelographic work to date), “Moscato Bianco does best on marly-clay soils, specifically those formed in the Middle and Late Miocene eras (especially the former), a fact apparently known to our ancestors.”
The Moscato d’Asti DOCG lies in the north-westernmost area of the Po River Valley along the southern edge of the river basin. It shares with its sister appellations to the west — Barbaresco, Barolo, and Tortona — the same Miocene-era ancient seabed sedimentary subsoils that run from the beginning of the river basin to roughly its middle (where the gypsum starts to appear in greater abundance in what is known as the Sulfurous Gypsum Formation or Formazione Gessoso Solfifera in Italian, one of the defining geological characteristics of the Apennines to the southeast; Barbaresco, Barolo, Tortona, and Asti are located in the “pre-Apennines,” where the mountain chain begins to take shape).
No one knows exactly why these ancient soils work so well with fine wine production and scientists and wine growers continue to argue about what the reasons are. But all agree that nutrient-poor soils like these are ideal for creating distinctive aromas and flavors in wine. Ancient seabed is something that many of the greatest wine producing regions of the world have in common: Burgundy, Barolo and Barbaresco (as above), the Santa Cruz Mountains in California and the Willamette Valley in Oregon all share these same ancient seabed soils, for example. Given this shared pedigree, it should be no surprise that Moscato d’Asti deserves its place among the great appellations of the world.
In our next post, we’ll look at the second paragraph in the DOCG specifications and why Moscato d’Asti is so uniquely suited for the production of these wines.