The measuring of 87Sr/86Sr in wine, grape, and bioavailable soil fraction samples with the same uncertainty of geological materials allows fully comparing the whole wine-production chain with the peculiar geochemical isotope signature of any geographic area. Indeed, this signature is the same as the final product inherited by the soil bioavailable fraction and, in turn, by the geological substratum of the vineyard. On the other hand, the few data available in literature that referred to white wines cast doubts for the use of this geographic tracer due to the common use of geological derived additives, such as bentonite, in the white wine-making procedure, which may overprint the original geochemical signature of the vineyard substratum. To tackle this issue, we analyzed the Sr-isotope compositions of four white wines produced over a period of almost 10 years in a high-quality organic farm, located on the volcanic units of the Vulsini Volcanic District (southern Tuscany, Italy). The 87Sr/86Sr values of rock, soil, grape, grape juice, must, and wine were compared among them and further weighted against the isotope fingerprint of the bentonite and yeast employed during the wine-making process. The 87Sr/86Sr values from the entire white-wine production chain reveal that no variations are observed from the signature imprinted by the original geological substratum (rocks and soils), suggesting that no further contribution is given by the addition of bentonite and yeast to the white wine Sr-isotope values. On the other hand, intermediate 87Sr/86Sr compositions are found when grapes from different vineyards are used for making multi-cultivar wine blends. Indeed, the experimental data clearly show that the Sr isotope composition is maintained through the wine-making process for white as well as for red wines. Both grape and final wine preserved the isotope signature inherited from the labile fraction of the soil where the vines are farmed. Our data thus confirm, also for white wines, the robustness of the Sr-isotope tool in studies where it is important to define terroirs and geographic provenance.

中文翻译：

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白葡萄酒酿造过程中 87Sr/86Sr 的保护：地理来源和优质生产的地球化学指纹

在具有相同地质材料不确定度的情况下测量葡萄酒、葡萄和生物可利用土壤组分样品中的 87Sr/86Sr，可以将整个葡萄酒生产链与任何地理区域的特殊地球化学同位素特征进行充分比较。事实上，这种特征与土壤生物可利用部分以及葡萄园的地质基质所继承的最终产品相同。另一方面，由于在白葡萄酒酿造过程中普遍使用地质衍生添加剂（如膨润土），可能会套印，因此文献中提及白葡萄酒的少数可用数据对这种地理示踪剂的使用产生了怀疑葡萄园基质的原始地球化学特征。为了解决这个问题，我们分析了位于 Vulsini 火山区（意大利托斯卡纳南部）的火山单元的优质有机农场在近 10 年内生产的四种白葡萄酒的 Sr 同位素组成。岩石、土壤、葡萄、葡萄汁、葡萄汁和葡萄酒的 87Sr/86Sr 值在它们之间进行了比较，并进一步根据酿酒过程中使用的膨润土和酵母的同位素指纹进行加权。来自整个白葡萄酒生产链的 87Sr/86Sr 值表明，从原始地质基质（岩石和土壤）的印记中没有观察到任何变化，这表明在白葡萄酒中添加膨润土和酵母没有进一步的贡献。白葡萄酒 Sr 同位素值。另一方面，当来自不同葡萄园的葡萄用于制作多品种葡萄酒混合物时，会发现中间 87Sr/86Sr 成分。事实上，实验数据清楚地表明，在白葡萄酒和红葡萄酒的酿酒过程中，锶同位素组成得以保持。葡萄和最终的葡萄酒都保留了从种植葡萄藤的土壤的不稳定部分继承的同位素特征。因此，我们的数据也证实了，对于白葡萄酒，锶同位素工具在定义风土和地理来源很重要的研究中的稳健性。葡萄和最终的葡萄酒都保留了从种植葡萄藤的土壤的不稳定部分继承的同位素特征。因此，我们的数据也证实了，对于白葡萄酒，锶同位素工具在定义风土和地理来源很重要的研究中的稳健性。葡萄和最终的葡萄酒都保留了从种植葡萄藤的土壤的不稳定部分继承的同位素特征。因此，我们的数据也证实了，对于白葡萄酒，锶同位素工具在定义风土和地理来源很重要的研究中的稳健性。