The objective: dealcoholization and preservation of aromas

Non-alcohol wines are known for several years now but are you aware of the  methods used to obtain a 0.0% alcohol beverage keeping full aromatic potential ?

First thing to know is that the dealcoholization of a wine is a tough exercise that can have significant effect on the quality of aromas.

As time passes  it has become clear that, instead of extracting the alcohol  in a finished wine, the process can actually be carried out at various stages of the production process.

  • By choosing grape varieties that produce low sugar levels
  • By dividing the harvest into two stages: one to harvest less ripe grapes with higher acidity levels and a second one to harvest the riper grapes. The two harvests are then reassembled.
    However, we know that harvesting unripe grapes results in wines with low alcohol levels and we also know the sensorial quality is significantly affected with high acidity levels and unpleasant flavours.
  • Using enzymes such as glucose oxidase, will results in reduced residual sugars and will half potential alcohol level in the finished wine.
    This treatment has its limits as the use of this enzyme is not authorized in wine production and can only be used for white wines.
  • By limiting the fermentation of bacterial strains in order to reduce alcohol level. This practice can not be used for all types of wines.
  • By using a yeast with low alcohol yields, which is both inexpensive and easy to implement. These strains are obtained by modifying their metabolism in order to turn some of the sugars into sub-products other than ethanol (16.8 g of sugar per degree of alcohol).

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 (aromas) 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.
Finally in order to reduce alcohol levels  a volume of water equal to the one eliminated by reverse osmosis needs to be added to the osmosed wine. 

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, 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 de-aromatized and reintroduced into the dealcoholized wine and this fraction is then reintroduced into the total volume of wine to be processed.
This technique is based on distillation and heat 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, Domaines Pierre 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.