DIETHYLENE GLYCOL

Sometimes unscrupulous winemakers resort to using illegal additives to enhance, stretch or otherwise modify their products (kind of like the milk powder scandal in China not long ago).
Fortunately there haven't been any major ones in New Zealand that have resulted in death or injury but in other countries this has happened.
One of the illegal additives is diethylene glycol which is a principal ingredient in the manufacture of anti-freeze. It has been used to increase the apparent sweetness in wines which in countries like Germany and Austria often determine quality gradings and therefore price. DEG has also been linked to scandals where it has been used in toothpaste and pharmaceuticals in various countries around the world. Excessive amounts can cause blindness, kidney failure and death so it is taken very seriously when abuses are discovered.
In 1985 I had firsthand experience of the Austrian wine scandal where DEG was found to have been deliberately used in some wines to give them a higher grading. I was brand manager for a famous Austrian brand and on learning of the problems in Austria I contacted the brand owner to seek assurances that the product we had imported was safe. These were duly given. As a back-up I sent samples of the wine to a testing laboratory and DEG was discovered at unacceptable levels. When told the brand owner expressed surprise and after lengthy telephone negotiations (pre-internet days) I extracted compensation for the thousands of cases of wine that we had imported and had these destroyed under customs supervision. We ceased to import the brand. It took many years for the Austrian wine industry to recover from this scandal.

Not long ago I opened a half bottle of a German trockenbeerenauslese wine. It was a 1992 vintage that I had bought many years earlier on special in a wine shop. The wine was thick and very sweet as a TBA should be but it gave us a tremendous headache. I can only assume that DEG or some other additive had been used to enhance the sweetness ranking of this wine (trockenbeerenauslese being the highest ranking of sweetness in German wines and commanding the highest prices).