Sortenreinheit

Sortenreinheit, literally “variety purity” in German, denotes the degree to which a product derives from a single plant variety with little or no contribution from other varieties. It is a key concept in agriculture, horticulture, and the food and beverage industries, where varietal identity influences flavor, aroma, appearance, and regulatory labeling.

In wine, Sortenreinheit describes wines made from a single grape variety without admixture of other varieties. For varietal labeling, many jurisdictions require a high threshold of purity, commonly around 85% of the named variety, with higher or 100% purity required for certain classifications. In practice, producers may blend small amounts of other varieties for stylistic reasons, but doing so undermines varietal purity and the label.

In seed and crop production, Sortenreinheit is a formal criterion in seed certification and trade. Seed lots are tested for varietal purity using morphological assessments and genetic methods, and purity thresholds (percentages of the declared variety) are specified by national or international certification bodies. Non-pure lots may be rejected or sold as mixed lots with appropriate labeling.

Maintaining Sortenreinheit involves isolation of fields, controlled pollination, careful harvesting and processing, and rigorous cleaning of equipment. It is supported by labeling, traceability, and testing, including DNA-based methods in modern programs. Limitations exist: natural cross-pollination, seed mixing, and labeling errors can reduce purity. Nonetheless, Sortenreinheit remains essential for consumer expectations, regulatory compliance, and the integrity of varietal products.