In storage stages, in order to ensure proper wine preservation, it is necessary to create atmospheres with reduced amounts of oxygen. To achieve these results, the characteristics of two food gases can be exploited: argon and nitrogen.
SIAD, among Italy’s leading chemical groups, operating in the production and distribution of technical and natural gases, compared the two methodologies to show their potential and advantages in oenology.
Protective atmosphere in the winery
In the cellar, during tank storage stages, wine can be protected by using argon and nitrogen or their mixtures possibly containing CO2 as well. The operating methods are different and are related to the peculiarities of each solution, as well as the construction characteristics of the tanks.
The process consists of two steps:
- Reclamation and static protection: air contained in the tank is removed by introducing gases, before the introduction of wine
- Dynamic protection, involves the delivery of gases to maintain the compositional conditions of the atmosphere at optimal values during the emptying of wine from the tank.
Argon decontamination and protection
Remediation and protection with nitrogen must consider the density of this gas, to practical effects equal to that of air: for this reason, it can only be used as a diluent. Introduced into the tank, it mixes with the atmosphere present, reducing the oxygen content.
During the emptying stages, the composition of the atmosphere inside the tank must be maintained at optimum values by introducing a volume of nitrogen equal to the volume of wine extracted.
The technique involves the use of gas delivery lines equipped with double-acting valves: during filling they let out a volume of internal storage mixture equal to the volume of wine introduced; during emptying they let in a volume of nitrogen equal to the volume of wine removed.
For the previous operations to be effective, it is necessary for the tanks to be able to operate under slight overpressure, several tens of millibars, in order to avoid introduction of air from outside.
Argon decontamination and protection
Being heavier than air, theargon involves different operations than the use of nitrogen. For its optimal utilization, i.e., containment of the required amount, its higher density compared to air must be taken advantage of and operate in such a way as to not dilute but move the air contained in the storage, introducing it from the bottom and letting the air escape from the top, operating in a “piston flow” type mode.
In this case, tanks are not required to meet special technical requirements,as long as the gas tightness makes it possible to maintain the correct atmosphere composition, at most with limited refills of argon during the storage time.
Of course, tanks suitable for nitrogen are also suitable for use with argon.
Argon and Nitrogen compared
All of the methodologies described above are also suitable for use with fully automated managed plant solutions. The one with nitrogen is the simplest by having fewer variables to manage.
The choice between one or the other solution will depend on the evaluation of a number of factors, including:
- Type of storage
- Costs of any plant upgrades and gas used
- Management aspects
Find out which solution is best suited to your winery’s winemaking processes, write to our experts: foodandbeverage@siad.eu
