For a few years now we have been talking to you about de-alcoholised wine-based drinks, but do you know how we go about promising you a product with an alcohol content of less than 0.09% while retaining all the flavour potential of the product?
First of all, you should know that the de-alcoholisation of a wine is a delicate exercise which can greatly affect the quality of the flavours.
Over the years, it turned out that instead of extracting the alcohol content from the finished wine, the process can be carried out at different stages of production.
- By selecting grape varieties that produce little sugar.
- By carrying out vine training methods which consist in dividing the harvest into two phases: one to harvest more acidic and less ripe grapes, the other to harvest more ripe grapes. The two harvests are then brought together. When harvesting a grape that has not yet reached maturity, we know that this leads to wines with a low alcohol content, and we also find that the sensory quality is greatly affected with an unpleasantly acidic flavour. As such, we seek to ensure that the grapes ripen while maintaining low alcohol content. For this, several factors come into play: the growing method, the selection of the plots of land and the reduction in leaf area.
- By limiting the fermentation of bacterial strains to reduce alcohol content. Fermentation takes place in conditions that are restrictive for yeast (low temperature, no addition of nutrients), which therefore consumes more sugar to produce 1% of alcohol. This method does not apply to all types of wine.
Three techniques are used to dealcoholize a finished wine.
Vacuum distillation, which is divided into two stages.
The first involves transferring the wine through a distillation column and extracting the highly volatile compounds (flavour) in a small alcohol fraction at 30°C.
The second stage is to transfer the wine through the column a second time in order to remove the alcohol.
The membrane process of reverse osmosis
Reverse osmosis is a form of nanofiltration which eliminate the mix of water and alcohol with other small molécules, such as organic acids or potassium known as permeate.
The process involves three stages. Firstly, the wine undergoes reverse osmosis in a closed circuit until the desired alcohol volume is reached.
The second stage is to separate the wine into two streams, one containing lightweight molecular compounds and the other containing the compounds held by the membrane.
Spinning Cone Column (SCC), widely used in the USA and Australia. This is the fastest, most efficient and most profitable method for collecting and preserving volatile compounds (aromas) in a wine at low temperatures.
This technology uses thin fill evaporation at very low temperature, created by the rotation of cones, and the stripping of the vapor obtained using a vacuum process with a small amount of the wine. Only a part of the dealcoholized wine is processed. This volume is first ‘de-aromatized’ and significantly dealcoholized. The previously extracted aromas are dealcoholized and reintroduced into the dealcoholized wine.
This technique is based on vaccum distillation and at low temperature process and enable us to adjust the alcohol level without losing aromas.
Following our deep research into the different techniques we have concluded that best results are achieved when the process is carried out on a finished “wine”.
In order to dealcoholize Pierre Zéro range, Chavin has chosen the Spinning Cone Column technique which has been proven to be the most effective in adjusting alcohol levels and reintegrating the most volatile aromatic fraction. It results in alcohol free wines with exceptional tasting qualities with no restrictions.