In winery operations it is usually necessary to form protective atmospheres that are low in oxygen or even completely devoid of oxygen, as well as to achieve modest refrigeration. In these cases, CO2 solids proves to be a valuable process ally, which, in addition to its ability to reduce the presence of oxygen in the air, has the characteristic of lowering the temperature of the grapes and/or crushed grapes, albeit in a very small way. If significant refrigeration is needed, CO2 remains one of the main gases, but used in the liquid state and in special exchangers.
Carbon dioxide in the solid state can be used in two different ways: in the form of dry ice or carbonic snow. The latter mode offers some unquestionable advantages, in terms of supply and management in automation.
Among the leading Italian chemical groups, operating in the Technical Gas, Engineering, Healthcare, LPG and Natural gas sectors, SIAD has developed solutions capable of meeting the needs of the various stages of wine processing. Specific gases, mixtures and equipment allow the grapes and crushed grapes to be refrigerated, operate with oxygen-free atmospheres and use less sulfur dioxide.
Protective atmospheres in enology
In oenology, protective atmospheres made with CO2 solids prove particularly useful in some stages of grape processing, mainly:
- In transporting from the vineyard to the winery
- In the grape receiving hoppers
- In stemming and pressing.
The amount to be used depends mainly on the volume and capacity of the equipment involved to limit its dispersion to the outside world.
Carbon snow, applications and benefits
Carbonic snow means CO2 in the solid state that is formed as a result of the expansion of gas in the liquid state contained in cryogenic tanks or cylinders.
On a practical level, mainly for performance and economic issues, only cryogenic tank training is considered.
One of the main advantages lies in its production: it can be obtained, in fact, directly at the winery by means of special snowmakers. Availability, therefore, is immediate based on the need of the winery that manages its production.
Snow management can be of two types:
- Manual: consists of the operator producing snow, handling and distributing it in a manner similar to that used for dry ice
- Automated: allows snow to be dispensed directly to points of use such as grape receiving hoppers, grape stalk removers, grape/pressure transfer pump hoppers, etc. by means of solenoid valves whose opening/closing is regulated in automation
Snow production from cryogenic storage and with snowmakers in common use can reach up to 400 kilograms per hour.
Dry ice, procurement and management
Dry ice, on the other hand, refers to CO2 in the solid state, in various geometric and dimensional forms (pellets, blocks, and tiles), obtained from the compression of carbonic snow
Dry ice of interest for winery applications is in the form of pellets or granules with a diameter of 3 or 16 millimeters.
Unlike carbonic snow, dry ice is not produced on-site, but supplied to the winery in special insulated containers, such as Styrofoam boxes or in isothermal crates containing, usually, up to 150 kilograms to then be applied as needed and in use.
Because of its temperature (-78 °C), dry ice tends to absorb heat and sublimate, decreasing in weight. Its shelf life depends on its shape and the type of container in which it is kept as well as the absorption of moisture from the air, which causes it to become compacted, resulting in difficulty in use.
Dry ice should be stored in suitable rooms to ensure the safety of operators. Unlike carbonic snow, it can only be moved manually.
From a quality point of view and in case of application on grapes, carbonic snow is to be preferred to dry ice because the former is easily distributed over the mass minimizing, compared to pellets, the risk of cold burns.
SIAD’s solutions for enology.
In light of the new needs of the wine market, SIAD has taken on the task of reinterpreting the potential of gases, with the understanding that even similar needs, but in different winery contexts, need different solutions, tailored to different realities. This is the origin of the working method that takes the form of close cooperation with the client to enhance the client’s specificities.
SIAD’s solutions for oenology are based on the properties of gases, optimized by technologically advanced plants: carbon dioxide used from the vineyard to fermentation; nitrogen and argon from fermentation to bottling; and oxygen for micro- and macro-oxygenation and in wastewater treatment.
