Diethylene glycol (DEG) shares many properties with glycerine. It is a clear, odourless liquid with an affinity for water. Glycerine depresses the freezing point of water, so it is an effective anti-freeze. It has a sweet taste.
Unlike glycerine, DEG is toxic.
The LD50 for DEG is around 40 grammes. (LD50 is gruesome shorthand for the lethal dose causing death in 50% of an average population.)
In 1985 I lived in a Germany divided by a wall. Fences and minefields stretched 1,393 kilometres from the Baltic Sea to Czechoslovakia. West Germany was prosperous, and its citizens had a taste for sweet desert wines. Austria produced many such wines. In 1985 German supermarkets contracted a number of Austrian wine producers to supply with cheap, sweet wines.
The Austrian Wine Scandal
1985 was not a good year for Austrian wines. Many of them did not meet the German supermarket standards for sweetness and body. A number of producers attempted to increase both the sweetness and body of their wines by adding DEG. German laboratories carrying out quality testing discovered the adulteration. Fortunately, the scheme was discovered before anyone was poisoned. But the reputation of Austrian wines was compromised. The Austrian wine industry collapsed. Five years later East and West Germany were re-united, but it took a further 25 years for Austria’s wine market to recover to its 1985 value.
The use of DEG exacerbated the Austrian wine scandal. It would have been illegal to adulterate wine with glycerine, but not potentially fatal. DEG might have been chosen despite its toxicity because it added more sweetness and more body to a wine than glycerine. Or maybe those adulterating the wine confused DEG with glycerine.
DEG poisoning continues
Sadly, there have been other incidents involving DEG poisoning, and some have been fatal. Most concern pharmaceutical products produced and used in Africa and Asia. Many of these products contained glycerine contaminated with DEG. One recent poisoning incident in Brazil involved beer. The brewery used DEG as a refrigerant, and an undetected leak contaminated the beer. The contaminated beer fatally poisoned ten people.