Peter Liem's case for a single grouping for the Val du Petit Morin, Côte de Sézanne, Vitryat, and Montgueux Champagne zones is weak

In his best-selling book Champagne: The Essential Guide to the Wines, Producers, and Terroirs of the Iconic Region, Peter Liem unveiled a new and unconventional schema for the Champagne sub-regions. I have been adhering to this schema in my exploration of the "Great Growers" of Champagne but find myself in opposition to his classification covering the areas Coteaux du Morin (Val du Petit Morin), Côte de Sézanne, Vitryat, and Mongueux. I clarify my opposition in this post.

The Union de Maisons de Champagne schema has historically been the lens through which the Champagne region has been viewed. In this schema, the four growing zones mentioned above have been included in the Côte des Blancs sub-region. Liem has grouped them together (shown in the graphic below) because, he says, they are new plantings.

As Liem describes it, the vineyards of Champagne were decimated, sequentially, by the Phylloxera epidemic, the First World War, and economic depression, and The Second World War. Prior to the Phylloxera infestation, the region was home to 60,000 ha of vineyards, almost double today's 34,000 ha. Following the conclusion of WWII, interest in the Champagne region was rekindled and large scale replantation was begun. By the 1960s and 1970s that interest begun to extend to the zones under discussion; zones which "had lain fallow for the last half century."

According to Liem:

Today, these viticultural areas are established, yet there are still fewer grower-producers in these regions than in others, with growers selling most of their grapes to houses or cooperatives. This means that it's still early days yet for deciphering the characteristics of the soil, climate, and exposure unique to these southern and eastern parts of the Champagne region.

Based on the foregoing, (i) there is no clearly definable reason for breaking these zones out from the UMC schema nor (ii) is there a clearly credible rationale for grouping them together.

As it relates to the geology of the region, the slow sagging of the Paris Basin caused an upthrusting of ancient geologic formations at the outer perimeter with each formation exhibiting as a concentric, outward-facing escarpment. In the case of Champagne, the escarpment is comprised of sands, marls, and lignitic clays of the Tertiary period capping chalk from the upper Cretaceous and, below Chalons, clays and sands of the lower Cretaceous.

The soils in the defined Champagne region is not monolithic, however. The Côte de Bars region of Champagne has Kimmeridgian soil of the same construct as the soils that underpin the vineyards of Chablis and Sancerre. In the Aisne region the upper Cretaceous has dipped into the Paris Basin  and the soil is comprised entirely of Tertiary clays and sands. In the area below Chalone -- referred to as wet Champagne -- the poor-permeability clays and sands of the lower Cretaceous period are dominant. The Champagne soils distribution is illustrated graphically below.

The chart above shows that Coteaux du Morin and Côte de Sézanne have source soils that are similar to the core Côte des Blancs and the broader Champagne while Montgueux and Vitryat seem to reside on a soil that is unique to the region. And Liem notes this in his book:

The Campanian chalk found in the Côte des Blancs or the Côte de Sézanne is what Champagne is famous for, but the chalk found here in Vitryat is different, hailing from the earlier Turonian Stage ...the chalk in Montgueux is Turonian, like the chalk in Vitryat.

While these zones are warmer, and do contain higher levels of clay than the soils of the more northerly vineyards, they are similar to the Côte des Blancs in the primacy of Chardonnay.

In summary (i) there is no clearly definable reason for breaking Coteaux du Morin (Val du Petit Morin), Côte de Sézanne, Vitryat, and Mongueux out from the UMC schema nor (ii) is there a clearly credible rationale for grouping them together. If pressed, I could agree to Montgueux and Vitryat, given their southerly locations and unique soil type, being joined in a separate zone. I do not see any benefits accruing from such a scheme, however.

©Wine -- Mise en abyme