Ancient Roman Wine

My wine news feed contained an article on ancient Roman wines. I like anything related to "ancient wine" and have blogged about it in the past:

• The Vix Krater
• 1540 Steinwein Tasting
• 8,000 Year Old Wine

So I needed to follow up on the link which lead me to Roman Wine Tasted 'Spicy', Archaeologists Reveal, an article in Newsweek.¹ The Newsweek article had a link to the original publication in Antiquity, called Making wine in earthenware vessels: a comparative approach to Roman vinification,² authored by Dimitri Van Limbergen and Paulina Komar. The authors noticed the similarities of grape vinification between the current Georgian method of using qvevri and the ancient Roman vessel called the dolia. Dolia were were highly valued items that were made by skilled artisans using specially selected clay mixtures.
The pictures below show examples of dolia fossa or wine cellars found in various locations in Italy.

From there they focused on aspects including their burial in the ground, shape, porosity and the role of skin-contact methods (when the grape skins remain in contact with the juice during winemaking) and flor yeasts (yeast cells that float on the surface of the wine).
Comparison of the Georgian qvevri and the Roman dolia:

• Dolia and qvevri are egg-shaped, porous clay vessels, which means that vinification is oxidative
• Excessive and harmful oxidation is prevented by the coating of vessel interiors with pitch (dolia) or beeswax (qvevri), which penetrate the clay, thus waterproofing and sterilising the vessels
• Both wood pitch and beeswax have excellent waterproofing capabilities, but the vessels remain porous to a certain extent, and this permits a degree of micro-oxygenation
• Burying and sealing the vessels further ensured ideal conditions for making fine oxidative wines

Here is what the authors surmise about ancient Roman winemaking techniques:

• Fermentation in Roman winemaking was spontaneous and entirely dependant on the yeasts present on the grapes
• Grapes were gently tread (foot stomped) and squeezed (without breaking stems and seeds, which imparts unpleasant flavours) and fermentation put in motion immediately to reduce the risk of failure
• Primary fermentation—the first so-called tumultuous phase in which the bulk of the sugars are turned into alcohol—lasted nine to 30 days, during which the dolia were kept open
• As the level of carbon dioxide increased during fermentation, the egg-like shape of the dolia and qvevri created internal convection currents gently stirring up (dead) yeasts, skins and other solids and slowly mixing them with the must, promoting a uniform fermentation and a homogenous must
• The jars were then topped up with more must (to minimise air contact) and sealed with a plastered terracotta disc (operculum) or wooden lid or simply with animal skins
• The practice of burying earthenware vessels ensured a constant temperature inside them, providing a stable environment for the wine to ferment and mature through the changing seasons
• Once sealed, the wine remained in the dolia for five to six months until they were opened at the spring equinox

The picture below is the schematic representation of the fermentation process in dolia/qvevri.²

Finally, the authors summarized that regardless of the color of the grape, the vinification more resembled current red wine vinification where the must was left in contact with the skins. They came to that conclusion based on the various colors of wines that were decribed by Pliny albus (pale white), fulvus (reddish-yellow), sanguineus (bloody-red) and niger (dark, black) as well as early Greek literature μέλας (black), λɛυκός (white), κιρρός (orange-tawny), ξανθός (yellow) and ɛρυθρός (red).

References:
1. Robyn White, Roman Wine Tasted 'Spicy', Archaeologists Reveal, Newsweek, January 22, 2024.
2. Dimitri Van Limbergen and Paulina Komar, Making wine in earthenware vessels: a comparative approach to Roman vinification, Antiquity, Cambridge University Press, 23 January 2024.