Increased attention in cellars – must gas can pose a serious threat

By: STA Date: 2025. 08. 21. 10:30

With the arrival of this year’s harvest season, the National Food Chain Safety Office (Nébih) is drawing the attention of wine producers to the dangers of must gas generated during must fermentation. Inhaling must gas in high concentrations can even cause tragedy if the cellar is not properly ventilated. The safety of the cellar air can now be checked with carbon dioxide detectors, but the traditional candle method can still provide a simple and effective warning.

(Photo: Pixabay)

The 2025 harvest season began a few days ago with the picking of the earliest-maturing grape variety in our country, the Csabagyöngye. In many cellars, the must from the harvested grapes is already in the spring, meaning that fermentation has begun. This is a special period always awaited with great excitement in the lives of grape growers and wine producers. However, it can also pose serious dangers if we fail to take the precautions that can prevent tragedies caused by must gas generated during fermentation. Must gas, which is actually nothing more than carbon dioxide, can accumulate in such quantities in a cellar with inadequate ventilation that it can lead to serious, even fatal, poisoning.

Nébih draws the attention of wine producers to the fact that continuous monitoring of the air quality in the cellar is particularly important at this time of year

In addition to the use of modern devices, such as carbon dioxide indicators, the centuries-old method of checking with a candle flame can also warn of danger. The essence of the candle check is that if the flame of a lit candle held at waist height, for example attached to a shovel or stick, goes out or only burns uncertainly, it indicates an increased carbon dioxide content in the air. Since carbon dioxide is heavier than air, it primarily collects in the lower part of the cellar, so it is particularly important to always use the candle at waist height or lower. In such a case, entering the cellar is life-threatening.

Whether using the candle method or a modern alarm system to detect the presence of must gas, leave the room immediately and call 112 for help from professionals (fire department, disaster management).

Nébih also draws the attention of winemakers to the fact that registered wineries must have a written action plan to avoid accidents caused by the danger of must gas. It is advisable to place a short information sheet at the entrance to the cellars for this purpose. In order to provide adequate information, all cellar workers must participate in repeated accident prevention training in the period before the harvest. In addition, continuous maintenance of the sensors must be ensured (at least once a year in the period before the harvest), and this must also be documented.

Nébih