Study finds older Riesling vines do not produce richer aroma profiles.

A new study published in OENO One found that older Riesling vines did not consistently produce berries with stronger secondary metabolite profiles than mature vines in a controlled vineyard trial in Germany, a result that challenges a long-held belief in parts of the wine industry that greater vine age automatically leads to higher quality fruit.

The research focused on Vitis vinifera L. cv. Riesling in the Rheingau region, at an experimental site in Geisenheim, and followed three consecutive vintages from 2015 through 2017. The vineyard offered an unusual test case because it contained adjacent rows of the same Riesling clone grafted onto the same rootstock, but planted in different years. The oldest vines were planted in 1971, the mature vines in 1995, and the youngest vines in 2012. That design allowed researchers to compare age groups while limiting many of the outside factors that often complicate similar studies in commercial vineyards.

The authors said scientific evidence on vine age has remained limited because older and younger vineyards usually differ in many ways beyond age, including soil conditions, microclimate, disease pressure, management history, and replanting patterns. Old vineyards also tend to be valued as cultural heritage, and in many wine regions they are associated with superior wines, even when the direct biological basis for that belief has not been clearly established.

In this trial, researchers examined berry secondary metabolites that are important to Riesling aroma and wine style. They measured free and bound monoterpenes, C13-norisoprenoids, and skin flavonols. These compounds are linked to floral, fruity, and, in the case of TDN, kerosene-like notes that can shape the character of Riesling wines. They also analyzed flavonols in the skin, compounds that are less central to aroma but still matter for wine typicity, bitterness, and astringency.

The results showed a general tendency for the youngest vines to accumulate higher amounts of several aroma-related compounds per berry across the three vintages. According to the study, young vines had significantly higher amounts of bound nerol oxide, vitispirane, and 1,1,6-trimethyl-1,2-dihydronaphthalene, or TDN, than the older groups. Those differences were strongest in 2015, the first harvest year for the young vines.

The authors linked that pattern to the early stage of vine development. They said the youngest vines likely differed because of lower productivity, smaller root systems, and temporary differences in soil management. When the 2012 plantings were established, their rows were plowed during the first three years to reduce competition from cover crops, while the older rows already carried grass and clover. The researchers said those factors may have helped drive the higher accumulation seen in the youngest vines rather than age alone in a simple linear sense.

By contrast, the study found that mature and old vines were remarkably similar across most of the compounds examined. Statistical tests showed no meaningful difference between the 1995 and 1971 plantings for the compounds that stood out in the analysis. The researchers said this suggests that the main chemical shift may occur between the young and mature phases of a vineyard, after which the effect of increasing age appears to stabilize under the conditions tested in Geisenheim.

Flavonols followed a different pattern. Their levels changed more clearly with the growing season than with vine age. The paper reported higher values for quercetin-3-galactoside and quercetin-3-glucuronide in 2017 across all age groups. But the amount of quercetin-3-glucoside per berry, a point highlighted in the data, did not show a significant effect from either vine age or vintage.

Year-to-year variation still mattered. The study said 2015 had the lowest overall amounts of monoterpenes and norisoprenoids in berries. A principal component analysis found that the first three components explained 87.0% of the variance in the dataset, underscoring that seasonal effects and interactions among compounds remained important even in a tightly controlled setting.

Researchers chose to emphasize berry content rather than concentration alone because the youngest vines had smaller berries in 2015, which could create a concentration effect. They collected randomized samples of 200 berries for each treatment and replicate, and used gas chromatography-mass spectrometry to analyze monoterpenes and norisoprenoids, along with UHPLC methods for flavonols in berry skins.

The study does not say that old vines have no value. It instead narrows the claim that age by itself improves the chemical potential of berries. The authors wrote that under these specific experimental conditions, increasing vine age beyond maturity did not inherently enhance the oenological potential of Riesling berries. They also noted that their findings apply to one cultivar, one site, one rootstock-scion combination, and a limited number of vintages.

That distinction may matter for wine producers and the broader beverage sector, where old-vine status often carries commercial weight and can influence pricing, vineyard renewal plans, and quality narratives. The findings suggest growers may need to be more cautious about assuming that older vineyards will always deliver superior raw material on the basis of age alone. For wineries deciding whether to keep, replace, or market older blocks, the evidence points to a more nuanced picture in which site conditions, season, and management may matter as much as, or more than, the number of years since planting.

The paper also fits into a wider debate in viticulture. Vineyards in many regions are often replaced after 25 to 30 years because of falling yields, disease, or concerns about fruit quality, while other vineyards remain in place much longer if they stay productive and economically viable. By comparing vine ages within one vineyard and with matching plant material, the Geisenheim experiment sought to isolate a question that is difficult to test in normal commercial conditions.

The authors included Khalil Bou Nader, Éric Gomès, Doris Rauhut, Ghislaine Hilbert-Masson, Claus-Dieter Patz, Christel Renaud, Rainer Jung, Jean-Philippe Roby, Otmar Loehnertz, and Manfred Stoll. The study was received on June 19, accepted on September 15, and published on October 15 in OENO One.