A Drink for Emperors? Scientists Uncover the Secrets Behind Rome’s Finest Wines
A new analysis elucidates the tastes and methodology behind Roman wines — some of it fit for emperors
Roman wine, and ancient wine more broadly, is enigmatic. While notable Roman figures wrote about wines, their properties, and which varieties make good laxatives, they seldom clarified how specific practices led to specific flavors. They also never hid any away for 21st century scholars to imbibe and assess.
New research by archaeologists Dimitri Van Limbergen and Paulina Komar, published in the journal Antiquity, illuminates some of the mysteries surrounding Roman wine. They might have even discovered the secret behind Rome’s finest wines.
Rome had a unique method of vinification (winemaking). Unlike modern techniques where wine is fermented above ground in steel, oak, or concrete containers, Roman wine was fermented underground in clay containers called dolia.
Dolia cellars are found throughout Italy and former parts of the Western Roman Empire. They are found in particularly great abundance in urban centers like Ravenna, Pompeii, and Rome.
Only recently have dolia been considered worth studying. Recent analyses show they were made of clays extracted from select and often distant locations. As the authors note, “these vessels were highly valued items that were made by skilled artisans using specially selected mixtures.”
While prior studies on Roman winemaking reference dolia, none connect them to specific flavors or aromas. To better understand dolia and the wines they produced, Limbergen and Komar looked to Georgia.
Georgia and the surrounding Caucasus (land between the Black and Caspien Seas) are the earliest places where wine was fermented in this style. This history dates back to the early Neolithic and continues to the modern day. In Georgia, the practice is so well preserved it was classified a UNESCO World Intangible Cultural Heritage in 2013. They practiced this style of winemaking for over 8,000 years.
The earliest site in which earthenware vessels are buried is an Armenian cave, called Areni-1, which dates between 4,000 and 3,500 BCE. There are spherical ceramic vessels from Georgia dating to 5,800 BCE, suggesting the practice is even older. Researchers think these methods traveled to the Phoenicians who then took them to Italy.
Georgians called their vessels qvevri. Limbergen and Komar describe similarities between qvervi and dolia and why the Georgian vessel can help us understand Roman wines:
Dolia and qvevri are similar vessels in terms of material, shape and setting and the winemaking process for both vessels is broadly the same. Qvevri vinification procedures are, however, documented in much more detail. A comparative study therefore has the potential to greatly enhance our interpretation of the ancient textual sources on viticulture and winemaking.
In addition to vessel structure, Rome and Georgia have similar climates and used grapes with high genetic relatedness. The similarities further illustrate why qvervi are ideal for comparison.
Qvervi are built for natural wines, which means they use yeasts that occur organically on grape skins for fermentation. Roman dolia are the same. The main wine yeast is Saccharomyces cerevisiae.
S. cerevisiae is the wine-fermenting king. Not only does it eat grape juice sugars and turn them into alcohol (the name Saccharomyces alludes to the saccharide sugars it eats), it also produces enough alcohol to kill competing microorganisms, leaving more sugar for itself.
Yeasts like S. cerevisiae convert most sugars to alcohol early in the winemaking process. This stage is called primary fermentation. In Rome, primary fermentation lasted nine to 30 days.
Dolia were kept open during primary fermentation, which allowed carbon dioxide emitted from S. cerevisiae to escape the vessel. (If you bottle dolia too quickly, they can crack from trapped carbon dioxide.) The mixture was then capped with a wooden lid, animal skin, or terracotta disk (called an operculum). Once bottled, dolia were kept beneath ground for five to six months.
The Georgian practice is similar. This from the authors:
primary fermentation in qvevri lasts two to three weeks, during which the jars remain open… After two to three weeks, the vessels are sealed with a stone or wooden lid and covered with earth, remaining so for six to nine months.
Fine wines were transferred to new vessels and aged for much longer (typically five to 25 years). To sustain healthy aging, fine wines needed grapes with extra sugar.
More sugar means stronger wines: The more sugar in grapes, the more alcohol S. cerevisiae creates. Alcohol in turn prevents the formation of bacteria that degrade wine as it ages. The worst bacteria is Acetobacter, which turns alcohol into sour-tasting acetic acids (a key ingredient in vinegar). To ensure wines had enough sugar, Romans used sun-dried grapes or sun-dried grapes soaked in wine.
Rome used sugary grapes to prepare several strong, fine wines. The most acclaimed was Falernian. From another paper:
The most expensive and luxury wine of Rome was the Falernian wine (from Falernum region), … which could age well for dozens of years… Falernian would be amber in color and highly alcoholic. It was made from the Aminea white grape variety.
White grapes regularly yield amber-colored wines when made in dolia or qvervi. Limbergen and Komar note how:
Once primary fermentation inside a clay vessel is complete, the grape solids sink naturally to the bottom of the vessel, where they concentrate in its flat and narrow base. At this stage, these solids are removed for red wines, but for white wines they are left in contact with the [grape juice] for several months to extract colour [and other elements]. This results in dark yellow, amber-coloured wines… akin to what is described in ancient Roman texts.
Many of Rome’s finest wines were white, but there were of course others. According to Pliny the Elder (23 — 79 CE), Roman wine came in four colors: pale white, reddish-yellow, blood-red, and black.
Black wine likely came from a specific type of red grape. Its wine was notoriously difficult to digest and only recommended as a laxative. One paper noted this is not usually an attribute of quality wine. Galen (129 — 199 CE), the famous Greek physician, agreed. This from another paper:
It was not appropriate, as [Galan] wrote, to serve dry or sour wine, which was thick and black at the same time, during a symposium or wedding reception, as an offering to gods, or during any other occasion whatsoever.
Other wines were created through a mixture of grape type, contact with the pomace (the dregs of leftover grape skins, seeds, and stems), and various degrees of oxidation.
Dolia and qvervi are porous, which means their wines get exposed to oxygen after concealment. Significant oxidation allows Acetobacter bacteria to proliferate and turn wine into vinegar, but mild amounts create fine wines with a unique flavor. To mitigate excessive oxidation, the interior walls of dolia were coated with pitch. Qvervi were coated with beeswax.
Fine oxidative wines are usually drier and characterized by flor yeasts, primarily S. cerevisiae, that form atop the wine as it ages (called “flor” because they look like flowers). These yeasts only form when there is enough sugar for them to proliferate. When they do form, they secrete chemicals that affect a wine’s taste. The most significant of these chemicals is sotolon.
Sotolon-infused wines are spicy. To quote the authors, sotolon “imparts aromas of toasted bread, apples, roasted walnuts, and curry.” These spicy notes were important elements in fine Roman wines.
Rome underwent steps to ensure its best wines formed sotolon. Dolia were stored at optimal temperatures to develop S. cerevisiae flor yeasts and used prepared grapes with a high sugar content.
Low quality wines were often dressed up to mimic sotolon wines. Columella (4 — 70 CE), a Roman author who discussed wine at length in his De Re Rustica, wrote that cheap wine was often supplemented with fenugreek, a flower with sotolon-like tastes and smells. The addition was a post hoc attempt to emulate finer wines.
Limbergen and Komar point to research that followed Columella’s descriptions of the winemaking process to see what kind of wine they made. The wine was amber-colored and, according to volunteers who drank it, “very sweet and spicy.”
Romans employed many tactics to tweak the tastes of wine. Falernian wine, for example, came in both dry and sweet varieties. The dry version was likely untouched by additives, whereas as the sweet version might have been supplemented with honey. Whatever the variety, the final brew was likely spicy.
While the authors suggest more research needs to be done — especially on clay vessels and their contribution to taste — they have undoubtedly increased our understanding of fine Roman wines and their construction. If you want to drink like Claudius or Nero, traditional Georgian wine is your best bet. Alternatively, you could just find some fenugreek.
