When examining labels on German wine bottles, one notices a distinctive feature. These wines often display information rarely found on bottles from other countries: terms such as Buntsandstein, Löß, Muschelkalk, and Schiefer. Do you know what these refer to?
These are all names of rocks. Buntsandstein refers to colored sandstone, Löß to loess (wind-deposited silty sediment), Muschelkalk to shell limestone, and Schiefer to slate. When such names appear on wine labels, they are understood as designations of the soil type in the vineyard where the grapes were grown.
Vineyard soil characteristics are frequently discussed, and many consider this information to be of significant importance. However, beyond examples like those from Germany, direct labeling of soil types on wine bottles remains relatively uncommon. Why do German wines so often indicate soil types on their labels? What significance does such information hold? This article examines these questions based on research published in 2024.
Why Soil Types Appear on German Wine Labels
Why is soil type information commonly included on German wine labels?
While the varieties cultivated in Germany have been changing in recent years, Riesling remains the dominant variety. According to data published by the German Wine Institute (Deutsches Weininstitut, DWI), Riesling was cultivated on 24,388 hectares in 2023. This represents 23.5% of Germany’s total vineyard area. The second-place variety, Spätburgunder (Pinot Noir), occupied 11,519 hectares at 11.1%, illustrating Riesling’s substantial dominance.
Given the characteristics of the Riesling variety and its wines, practices such as barrel fermentation, barrel aging, and malolactic fermentation (MLF) are not typically employed with any enthusiasm. Against this backdrop, German wines have long been perceived as minimizing winemaking intervention. There exists a strong belief that these wines achieve an authentic expression of terroir. The practice of indicating soil types on labels is considered to have developed within this context. In other words, soil type designations on German wine labels function both as simplified symbols expressing terroir and as marketing information analogous to terms like “Barrique” or “Barrel fermentation” found on wines from other producing countries.
Soil Does Not Express the Taste of Wine
Grapevines absorb minerals from the soil through their roots. These absorbed minerals accumulate in the fruit. Therefore, wine expresses the taste of the soil in which the grapes were grown.
Such explanations remain widely encountered today. Additionally, at tastings attended by producers, one frequently observes stones from the vineyard displayed on booth tables alongside the wines. These experiences tend to reinforce the impression that soil is a critical factor determining wine flavor.
However, current scientific knowledge maintains a cautious stance toward such impressions.
Research on the influence of soil type on the sensory properties of wine has yielded inconsistent results, and no comprehensive scientific consensus has been established. However, the more limited hypothesis—that grapevines absorb minerals derived from soil substrate and, through their accumulation, impart distinct sensory properties to wine—has been refuted through scientific investigation.
Differences in soil cannot be separated from the climatic characteristics of the region in which they are located. Therefore, it remains unclear whether differences perceived in wines from different soil types genuinely derive from soil differences. Nevertheless, even under these circumstances, scientific investigation suggests that factors such as vintage and producer exert greater influence than soil differences.
Differences in soil type are positioned as exerting indirect influences on vine growth through variations in root penetration depth, nutrient availability, and plant-available water holding capacity.
The “Name” of Soil That Changes Wine Taste
While actual differences in soil type do not produce clear distinctions in wine flavor and aroma, it has been suggested that the “name” of the soil written on a label does alter wine taste.
An experiment was conducted in Germany collecting five wines each from four soil types (Buntsandstein, Löß, Muschelkalk, Schiefer), totaling 20 wines. This experiment examined what influence soil type designation on labels might have. All collected wines were made from Riesling grapes. However, other factors varied: production regions and producers differed, and vintages consisted of a mixture of 2020 and 2021. The evaluation was conducted with 20 wine professionals.
The investigation involved three experimental steps. First, each wine was presented without disclosing soil type information. Subsequently, the same wines were presented again, this time with soil type information attached. Finally, a blend of all 20 wines in equal proportions was presented. This blended wine was provided with only the soil type information varied. Subjects evaluated each wine on a 0-to-100-point scale based on presented descriptors. The influence of soil type information presence or absence on sensory evaluation was determined from differences in evaluation results.
The results were unequivocal. Clear differences in evaluation results were observed between cases where soil type information was presented and cases where it was not. Moreover, changes in evaluation results showed approximately consistent patterns for each soil type, as reported. These changes were also observed in descriptors related to so-called “mineral” character.
In other words, the influence of soil type on wine taste—which has been refuted from a scientific standpoint—was confirmed to occur independently of actual soil type. This influence arose from the visual information of soil name designation on the label.
This investigation was conducted exclusively with wine professionals. Therefore, whether similar results or trends would be observed among general consumers remains a topic for future investigation. However, it was demonstrated that, at least among a certain population, a gap exists between scientific knowledge and actual perception.
Soil Names Determine Wine Taste
The particularly significant result from this investigation was obtained from the comparison where different soil type information was attached to a blend of all 20 wines in equal proportions.
In this portion of the investigation, the same wine was effectively provided with four different soil type names attached. There was no difference in the wine. Nevertheless, statistically significant differences existed in the sensory evaluation results obtained. Moreover, patterns observed throughout the entire investigation were present in the trends of these changes. These results suggest that soil names on labels, independent of actual wine characteristics, influence consumer perception.
Among trends obtained through the investigation, the influence of the Schiefer designation showed particularly interesting results. Schiefer refers to slate. It is a soil type characteristic of regions such as Mosel and Nahe in Germany. Wines labeled with Schiefer consistently showed increased scores for the descriptors “sour” and “flinty.” Similar results were demonstrated not only for individual wines but also for the 20-wine blend.
“Flinty” is a descriptor commonly used to express flint-like aromas. However, geologically, flint and slate are entirely different materials. Even if grapevines were to absorb minerals from the soil, or if soil type directly influenced wine taste, indicating Schiefer soil could not produce flint flavors. Yet in actual evaluation results, the presentation of Schiefer information clearly led subjects to perceive flinty influence.
Soil Names as Expectation Manipulation
Evaluation results in which subjects perceived the presence of geologically unrelated minerals, or ceased to perceive previously detected aromas simply due to changed label information despite identical wines, are considered to demonstrate two possibilities triggered by soil-related information.
The first is heightened sensitivity to expected perceptions when soil type information is provided. This is partially explained as cognitive bias. By consciously anticipating the presence of certain characteristics, subjects may become more sensitive to detecting those characteristics.
Other investigations conducted previously have reported that certain aromas not identified in free descriptions without prior information became recognized when explicitly indicated.
The second influence derives from pre-existing images. This is explained by assimilation-contrast theory.
Assimilation-contrast theory explains that when the discrepancy between what is expected and what is actually perceived is small, an assimilation effect occurs whereby perception shifts toward expectation; conversely, when the discrepancy is large, a contrast effect occurs whereby perception is exaggerated away from expectation. In the present case, the discrepancy between pre-existing images (expectations) of each soil type and actual wine characteristics was likely relatively small. Therefore, assimilation effects likely occurred, with perception shifting toward pre-held images. The fact that actual sensory evaluation results changed merely by altering label displays on the blended wine demonstrates the existence of such influences.
What these results indicate is that soil name display functions not as objective information provision but as expectation manipulation toward consumers. Simultaneously, the existence of clear pre-existing images regarding the provided information becomes necessary. Indeed, in the German investigation, subjects possessed no clear pre-existing image for one of the four soil types examined. Therefore, presenting soil information for that type produced no clear influence on evaluation.
Soil Type as Narrative
Images evoked when soil type information is provided are based on specific images consumers already possess. Conversely, when clear pre-existing images are absent, no particular influence arises even if information is provided. Moreover, these images need not necessarily be shaped by objective communication of facts or their accumulation—as evidenced by Schiefer being associated with geologically unrelated flint.
These facts reveal that using soil type information more effectively requires, above all, preparing and establishing the desired image to be expected from that soil type. Rather than mere accumulation of facts, this mode of image-making, meaningful within a specific context, is precisely narrative in nature. As narratives become widely established, systematization of meaning shared within communities occurs. If soil can be positioned and established as narrative understanding, wines in those bottles will actually be perceived as having such flavors.
If soil-related information exists as narrative, this simultaneously suggests that differences in taste perceived from soil types are not natural scientific facts. Differences in taste perceived from soil types are products of recognition formed within culture and history. This is considered the reason why taste tendencies differ between wines presented with Schiefer or Muschelkalk information in Germany versus wines labeled with slate or limestone designations in other production regions.
Geologically, Schiefer and slate, Muschelkalk and limestone are fundamentally identical. Therefore, wines from these soils should inherently share common characteristics. However, this does not hold when pre-existing images tied to soil types rely on narrative. Narratives likely possess the cultural backgrounds of their respective regions, and different narrative content can be established for each location. If the narratives defining tastes perceived from soil types differ, then even with geologically identical soil types, the tastes perceived from them can vary.
In the German investigation, all subjects were wine professionals. Therefore, they likely possessed particularly robust pre-existing images. Under these circumstances, it remains unknown whether general consumers less knowledgeable about wine would exhibit similar trends. Some investigations suggest that even general consumers may possess pre-existing images regarding soil types. However, the degree of bias such circumstances demonstrate remains unknown at present.
Nevertheless, even such consumers, as they acquire wine-related knowledge, will gradually encounter existing narratives. The possibility that they will heighten the degree of bias cannot be denied.
For both consumers and producers, this research reveals that soil possesses greater value not in the soil itself, but in the images attached to it.
