Posca: The Sour Drink That Kept the Roman Army Moving

Ask someone what Roman soldiers drank, and the answer is usually "wine." That is only partly true. While wine certainly played an important role in Roman life, the everyday drink of many legionaries was something far less glamorous: posca. Made by mixing sour wine with water, posca was inexpensive, refreshing, and practical. It lacked the prestige of a fine vintage served at a senator's banquet, but it was exactly the sort of drink a soldier on campaign needed. In many ways, it was the sports drink of the Roman army, though with a much sharper taste. Would most people today enjoy drinking it?

Probably not.

But for Roman legionaries marching twenty miles a day with nearly seventy pounds of equipment on their backs, posca made a great deal of sense.

What Exactly Was Posca?

Posca was made by diluting acetum, wine that had turned sour and become vinegar, with water. Depending on the region or personal preference, herbs such as coriander, mint, or fennel might be added to improve the flavor. Some recipes may also have included a little honey, though the evidence suggests this was probably less common among ordinary soldiers. Unlike expensive wines enjoyed by Rome's elite, posca could be made from wine that was no longer pleasant to drink on its own. Rather than wasting spoiled wine, the Romans found a practical use for it. That practicality was very Roman.

Why Soldiers Preferred It

Roman soldiers spent much of their lives on the move. Long marches, summer heat, and physically demanding labor meant they needed to drink frequently. Water alone was not always a safe option. Although the Romans built remarkable aqueducts and understood the importance of fresh water, soldiers on campaign often had to rely on rivers, streams, wells, or temporary water sources. Mixing sour wine or vinegar into the water likely improved its taste and may have slowed the growth of some microorganisms, although it certainly did not sterilize contaminated water. The acidity also made the drink refreshing, especially during hot weather. Modern athletes sometimes add electrolytes or flavored powders to water after strenuous exercise. Roman legionaries reached for posca.

Not Just for the Army

Although posca is closely associated with the Roman military, soldiers were not its only consumers. Because it was inexpensive, it became a common drink among laborers, farmers, sailors, and members of the lower classes throughout the Roman world. Wealthier Romans generally preferred higher quality wines, while ordinary people appreciated posca because it was affordable and easy to prepare. Even so, it became so closely linked with the military that today it is almost impossible to mention posca without picturing a Roman legion on the march.

A Drink Mentioned in the Ancient Sources

Posca appears in several ancient texts, demonstrating that it was a familiar part of Roman life. One of the most famous references comes from the Gospel accounts of the Crucifixion. As Jesus hung on the cross, he was offered a sponge soaked in sour wine. The Greek word used in the New Testament refers to sour wine, which many scholars believe was likely the same type of drink commonly consumed by Roman soldiers stationed nearby. Pliny the Elder also discusses vinegar and its many practical uses in his Natural History, while military references and later Roman authors mention vinegar as a standard part of army provisions. Although no surviving Roman military manual includes a detailed recipe for posca, the combined literary and archaeological evidence leaves little doubt that it was a familiar beverage throughout the Empire.

What Did It Taste Like?

That is the question everyone asks at living history events. The honest answer is that nobody knows exactly. Ancient authors never left us a definitive recipe, and ingredients likely varied across the Empire. Some modern recreations use red wine vinegar, water, and herbs. Others experiment with white wine vinegar, honey, or spices. We usually have several gallons of our own version of posca at events, following that red wine vinegar, water, honey, and coriander seeds. The result is usually tart, slightly acidic, and surprisingly refreshing on a hot day, almost like a modern kombucha. Would it replace your favorite soft drink?

Probably not.

But after spending hours drilling in armor under the summer sun, you might understand why Roman soldiers appreciated it.

More Than Just a Drink

Posca is a perfect reminder that Roman history is often found in the ordinary details rather than the dramatic ones. Visitors are naturally drawn to shields, helmets, and swords, but something as simple as a wooden cup filled with sour wine tells an equally important story. It speaks to the daily lives of the men who marched across the Empire, dug camps every evening, stood watch on distant frontiers, and carried out the work that kept Rome running. Sometimes understanding history is not about imagining the great victories. Sometimes it begins with taking a sip of what was in a legionary's cup.

Legio XIIII, Protinus!