In the time of the Roman Empire, there weren’t many options to satisfy a sweet tooth. Honey was expensive and difficult to obtain, and sugar was somewhere on the opposite side of the world. The Romans’ solution to their problem took the form of artificial sweeteners.
Sapa was an artificial sweetener commonly used in the Roman Empire. Like many other artificial sweeteners at the time, sapa was created by boiling down unfermented grape juices until they had reduced; sapa, in particular, was reduced to a third of the original quantity in order to concentrate the natural sweetness of grapes. By itself, sapa is perfectly harmless, and its sweet flavor comes from the acetic acid in the liquid turning into acetate. However, the Romans boiled their sapa in lead pots, and the acetate ions would combine with lead ions in the pots they were boiled in, forming lead acetate. Romans, not knowing about the repercussions of lead poisoning, chose to cook their sweeteners in lead pots due to the sweeter taste of lead acetate. A Roman winemaker commented that brass vessels, comparatively, added the taste of copper rust, which doesn’t exactly sound delicious. Modern recreations of the sweetener find 240-1000mg of lead per liter of syrup. Research scientist Jerome Nriagu commented that 5ml of the syrup would be enough to give a person chronic lead poisoning.
Sapa was used both as a sweetener and preservative, and was added to fruits and extensively to wine to prevent spoilage. Unfortunately, considering that an average Roman drank close to a liter of wine each day, they would likely end up consuming close to 20mg of lead a day. Fun fact: the U.S. Centers for Disease Control sets the upper limit of lead for a human adult at around .1mg/L. Additionally, wealthy Romans were likely to drink even more wine in a day. The Emperor Elegabulus once drank so much wine in a drinking bout that it was rumored that he drank from a swimming pool of wine when he was alone.
The Romans also learned to make a crystal version of lead acetate, similar in appearance to sugar and salt. A late 4th-century cookbook titled Apicius contained 90 recipes with some form of lead among the 450 total recipes. Ironically, among the side effects of lead poisoning are a loss of appetite and a metallic taste in the mouth, so a Roman would indulge in more food in wine to make up, creating a vicious cycle of lead poisoning.
It is also of interest to note that Romans were aware of the dangers of lead. Pliny the Elder speaks of “noxious and deadly vapor” that emerged from lead furnaces. Red and white lead were known to be poisonous, despite their use in cosmetics and medicines. Lead served as an early form of birth control in this regard: sapa was used to induce abortions. Soranus recommended smearing white lead over the uterus to prevent conception. Dioscredes advised against taking in white lead internally, and Celsus and Galen both provide an antidote for white lead poisoning. A description of lead poisoning is even given in the middle of the 2nd century BC. Yet despite the consumption of lead being so common, there is no record of widespread lead poisoning until the early 7th century (AD), where a Byzantine physician described the symptoms as being prevalent in Italy and many other regions of the Roman Empire.
There is no way to truly know if the Romans understood the risks of what they were drinking. However, if you’re curious, the recipes for making sapa and other sweeteners have been well recorded, so you can experience the sweetener of the Romans too — just avoid cooking in lead pots.