The main components of wine after bottling
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Main chemical alterations happening during the transport of wine
Tartaric acid: it can undergo precipitation if the temperature of wine gets lower or if it hasn’t stabilized properly
Malic acid: if it is found in the wine, it can trigger anomalous fermentations but only if the temperature is higher than 18 – 20 °C
Acetic acid: if the temperature is higher than 15 – 18°C and with oxygen, it can rapidly add up and trigger acetic fault
Colloids: they can merge up and precipitate if the temperature is lower than 4 – 5 °C
Residual sugars: they can be fermented by bacteria or faulty yeast if the temperature is higher than 15 °C
Sulphur dioxide: molecular sulphur is the form the most likely protects the aromatic profile of the wine from alterations (biological and chemical). It decreases when temperatures are high as well as when oxygen is available
Issues related to alternation happening during transport at high temperature
- When temperatures are high (higher than 20 °C and subjected to the time of permanence) anomalous fermentation of the malic acid (if available) may happen thanks to the action of malolactic bacteria or by the residual sugar
- In addition, other metabolites may develop because of Brettanomyces (polluting yeast having a slow fermentation action) with subsequent production of carbon dioxide and issues related to the cloudiness of the bottled wine
- If the closure is made of cork, or if the bottle is kept vertically, with high temperatures it may dry up so its quality is compromised with possible losses of the product or production on acetic acid
- High temperatures lead to a fast action played by sulphur dioxide with subsequent losses of quality
- High temperatures enhance the flocculation of proteins so wine gets cloudy
Issues related to alternation happening during transport at low temperature
- In the case of low temperatures (lower than 8 °C and subjected to the time of permanence)
- There is the possibility that tartaric acid (if it hasn’t been stabilized earlier in a good way through the use of cold techniques or using auxiliary products (like meta-tartaric acid) creates some sediments in the bottle
- For red wines, low temperatures may loose up the colour with colloidal substances creating precipitations
Other issues about wine transport
- Breakages: bottles may break down if they are not properly packed. Should only one bottle in the box break down, it is still a problem since it could spoil the labels of all the other bottles. In addition, the spilt liquid can undergo microbial alteration (acetic hue and moulds) that attack the other bottle in the box
- Corks may get altered (they can swell or dry up)
- The loss of aromatic intensity along with the feelings of freshness of young wines
- Decrease in the general quality of the wine itself