Our archive contains several issues of the Georgian agricultural journal "Mosavali" (Harvest), published in 1912. These volumes hold valuable and unique information about traditional wine-making techniques in kvevris (clay vessels) and oak barrels. One particularly important topic is the preparation and cleaning of vessels before wine fermentation.
Interestingly, the basic principles of this cleaning method have not changed significantly since the early 20th century. The original article, written by Professor Petriashvili, is preserved in its original style and spelling.
“Every wine vessel, whether new or used, must be inspected before use — it should be tested for leaks and then thoroughly cleaned. If the vessel is new, it must be purged of any substances that could leach into the wine. Whether it’s a kvevri or a barrel, the first rinse should be done with cold water, followed by two or three rinses with boiling water to ensure the vessel is properly soaked and sealed.
After drying, barrels are rinsed with a sulfuric acid solution (1 part acid to 15 parts water), while kvevris are washed with tartaric acid (1 part acid to 5 parts water). Barrels are rolled back and forth, and kvevris are scrubbed with a brush to ensure all inner surfaces are wet. The same acid solution can be reused for 7–8 vessels.
Afterward, the vessel is rinsed several times with cold water and left filled with clean water for at least a day. Finally, it is rinsed again with boiling water and a final flush of cold water. After drying, it’s also advisable to rinse the vessel with a small amount of wine.
Used vessels require more careful cleaning, especially if mold or residue is present. Ideally, a vessel should be cleaned immediately after use to avoid deep cleaning later. This involves brushing or scrubbing the inside with a broom or cloth and rinsing, ensuring every bit of wine residue is removed. After drying, the vessel is fumigated with sulfur, which releases sulfur dioxide (SO₂) — a crucial sterilizing agent. Fumigation should be done monthly during storage. Before use, a simple rinse with cold water is sufficient.
If a vessel is left uncleaned, it will develop mold and an unpleasant odor and taste. Residual wine sludge spoils quickly and will ruin any new wine placed in the vessel. To clean such contaminated vessels, the following remedies can be used.”**
There are many methods to clean kvevris and barrels, but none are completely perfect — the very number of methods proves that. The best solution is prevention: keep the vessel clean and fumigate it monthly with sulfur. Then, when needed, a simple rinse with cold water will be enough.
If deep cleaning is required, the most effective modern solution is to wash with Javelle water (sodium hypochlorite). It fully removes unpleasant odors, especially the smell of spoilage. After using Javelle water, vessels must be thoroughly rinsed first with hot and then with cold water.
Winemakers must pay special attention to the cleanliness of their vessels — not only the ones in use, but also the empty ones in storage. Both the cellar and the containers must be kept clean. Even one rotten stave in a barrel or a single moldy spot in a kvevri can spoil an entire year’s harvest.
