The strange situation with mature German Riesling is that it remains, despite decades of critical enthusiasm and a small group of collectors who know exactly what they are doing, genuinely undervalued. A ten year old Burgundy from a recognized producer will cost what it costs and will be contested at allocation. A twenty year old Spätlese from a Mosel estate that has been making wine on the same slate slopes for centuries can sometimes be had for less than a restaurant bottle of something inferior, because the name on the label requires knowledge that the average buyer has not yet acquired.
This is an opportunity, and it is not likely to last indefinitely.
I have been buying Prüm family Rieslings from the 1970s and 1980s with some regularity and find them, without exception, remarkable. Joh. Jos. Prüm, based in Wehlen on the Mosel, is among the handful of estates whose wines age with the particular authority that makes the effort of cellaring worthwhile. A Wehlener Sonnenuhr Spätlese from 1979 or a Graacher Himmelreich Auslese from 1983 is not, at this stage of its life, a museum piece. It is a functioning wine: concentrated, alive, with the acidity that has preserved it and the secondary complexity that decades of slow development have produced. The petrol note that serious Riesling acquires with age, a tertiary aromatic that alarms the uninitiated and delights those who know it, belongs to the wine the way dark chocolate belongs to a great aged Barolo. It is evidence of transformation, not deterioration.
Understanding the Nomenclature
The German Prädikat system is often presented as intimidating, which is unfair to both the wines and the people who might otherwise drink them. The logic is straightforward: the classifications describe ripeness at harvest, which correlates with sugar concentration, potential alcohol, and the relationship between sweetness and acidity that determines a wine's character and its capacity to age.
Kabinett is the lightest designation, grapes harvested at standard ripeness, wines of low alcohol (often seven or eight percent) and delicate balance. A fine Kabinett is among the most food versatile wines made anywhere. Spätlese, meaning late harvest, produces correspondingly riper grapes and greater concentration; these are the daily drinking wines of the serious cellar, capable of decades of development. Auslese means select harvest, individual bunches chosen for ripeness, producing wines that are richer, with more apparent sweetness, though the great dry Auslesen from cool vintages can be austere and architectural in structure.
Beerenauslese and Trockenbeerenauslese occupy a different category entirely: individual berries affected by noble rot, concentrated to a degree that requires patience few casual buyers possess. Eiswein, made from grapes frozen on the vine, produces a different style of concentration, higher acid, purer fruit, without the oxidative complexity that botrytis introduces. These are objects of contemplation as much as pleasure.
"A twenty year old Spätlese from a great Mosel estate can sometimes be had for less than a restaurant bottle of something inferior, because the name requires knowledge that the average buyer has not yet acquired. This is a genuine opportunity."
The additional classifications, trocken (dry), halbtrocken (half dry), feinherb (off dry, used informally by some producers when halbtrocken does not quite capture the style), describe the finished wine's residual sugar rather than harvest ripeness. A trocken Auslese is a paradox that confuses beginners: how can a wine made from ripe, sweet grapes finish dry? The answer is that fermentation converts the sugar to alcohol, producing a wine of high natural alcohol, pronounced body, and dry finish. These wines age differently from their sweeter counterparts and reward earlier drinking in many cases.
Why Acidity Is the Point
The reason great Mosel Riesling ages so well is not the sugar, though residual sweetness is part of the preservation equation. It is the acidity, the tartaric and malic acid levels that remain after fermentation and that create an environment hostile to the oxidative degradation that ends most wines within a decade of their vintage. The Mosel's slate soils, which retain heat during the day and radiate it through cool nights, permit slow ripening that preserves natural acidity while building flavor concentration. This combination, high acid and genuine concentration, is the structural argument for aging.
The practical implication for the buyer is that, unlike most wine categories in which the optimal drinking window is relatively narrow, great Mosel Riesling is remarkably forgiving of timing. A fine Spätlese at five years is a young wine showing primary fruit. At fifteen, it has begun to develop the petrol and honey notes of maturity. At thirty or forty years, from a great estate in a great vintage, it can be among the most complete wine experiences available at any price. The Prüm wines from the late 1970s are living evidence of this. Buy them now, while the market has not yet arrived at the price this quality deserves.