What is the aim of pasteurisation in wine-making?

Pathogen elimination and microbiological risks

In France, pasteurisation is not just reserved for milk, beer and cheese: wines can also be pasteurised. This process, which owes its origins to Louis Pasteur, sterilises food by exposing it to heat and high temperatures.

In the wine industry, pasteurisation stabilises the wine by eliminating its micro-organisms (bacteria, yeasts such as brettanomyces, listeria monocytogenes, etc.). The time the wine is exposed to the heat (around 72°C) is brief, lasting just a few seconds. The temperature rise and cooling must take place quickly, otherwise the quality of the wine may be compromised.

Used on a wide range of foods (cheese, beer, milk, etc.), this heat sterilisation treatment reduces health risks by eliminating pathogenic bacteria and bacteriological risks.

There are three different techniques for treating wine with heat:

• thermolisation or hot bottling (a technique less commonly used because it alters the quality of the wines),,
• flash pasteurisation (the most widespread technique),
• pasteurisation of wine in bottles.

A solution for difficult fermentations to stabilise the must

Flash pasteurisation or thermo-flash pasteurisation is also a recourse for winegrowers in the event of complicated fermentations, particularly when undesirable bacteria develop and harm the organoleptic quality. Flash pasteurisation stops fermentation. It also preserves all the essential components for maturing the wine. This thermoflash treatment does not affect the organoleptic qualities of the wine.

Flash-pasteurisation does not tolerate any approximations. This sterilisation process requires technical know-how and meticulous control of temperature and exposure time; many professionals are reluctant because of the negative impact of heat on the wine if the thermoflash technique is not carried out correctly.