Regarding illicit manipulations, see under wine adulteration.
Wine adulteration (colloquially known as "pantschen") is understood to be the deliberate, incorrect manipulation of wine-making processes in violation of wine law, carried out with deceptive or fraudulent intent. The aim is to "improve" the taste or quality by means of prohibited additives and thus falsely pretend a certain or better quality, to increase the quantities of high-quality wines by mixing them with simple, cheaply produced mass wine or simply by adding water, and to market wines under prestigious names or vintages by means of false labelling using real labels and/or bottles.
Regarding the question of what exactly counts as wine adulteration, there have always been different and often changing views throughout history. What is now considered adulteration may have been a widely practised practice just a few decades ago. Even today, some techniques are country-specific and regulated differently, especially in Europe versus the New World. Three significant examples are the regulations regarding fortification, acidification and sweetening. The introduction of strict wine laws in many wine-growing countries beginning at the end of the 19th century had a positive effect. For some wine-growing regions they already existed before that. Of course, this did not completely prevent manipulation.
The 18th century in particular is considered the "century of wine scandals". The enormous demand for port wine in England led to bottlenecks from 1730 onwards. Therefore, simpler wines on the Douro were spiked with alcohol, elderberry juice, ginger, pepper, cinnamon and sugar. The positive effect was that in 1756 the port wine region was declared one of the first areas to be protected in terms of origin and strict laws were passed. In Bordeaux, it was common practice on a large scale to blend the wines for the English market with high-alcohol, simple wines from other areas (Rhône, Spain). When there was a great shortage of wine in France due to phylloxera and mildew, sultana wine was produced in large quantities from 1880. In the 19th century, there were mass fakes of Hungarian Tokay in many countries, and books even had detailed recipes for them.
The great breakthrough in the fight against counterfeiting began with the definition of controlled designations of origin. These originated in France with the appellation system at the beginning of the 20th...