Partenaires




Accueil du site > ANGLAIS > Your problem > Fine wine expertise > Fine wine expertise


Fine wine expertise

All the versions of this article: English , français

Two physical analysis methods are developed in the lab, and applied to authenticate old bottles of fine wine. The advantages this approach is to allow non-destructive expertises (that is to say without opening the bottle) to estimate, on the one hand the age of the wine, and on the other hand the date of manufacture of the bottle.

Two analysis methods are:

  • Gamma spectrometry by low background for the detection of Cesium137 (Cs137) into the wine,
  • The method of fluorescence X induced by charged particles produced by accelerator, to determine the chemical composition of the glass bottles (PIXE method : Particle Induced X-Ray Emission).

The wine is absolutely not affected by these two types of analysis, and the bottle may return to the commercial circuit after authentication and insertion of a seal.

-I- Wine dating

The artificial radioactivity was created on the earth by the first atmospheric nuclear tests in the beginning of the 50’s. Radioactive species like Cesium 137 (Cs137) are diluted in the upper atmosphere, and then fall on plants and animals on the soil surface. After deposit on grapes, radioactivity is locked in the wine bottle during the winemaking process. The bottle is placed in front of a highly sensitive detector to count gamma-rays emitted by radioactive nuclides, and especially Cs137. This radiation passes through the glass of the bottle and gives the information of the content of radioactivity in the bottle to expertise. The content of Cs137 in the wine has changed over time, therefore it’s possible to estimate the vintage from measurement compared to our reference curve established in the lab.

-II- Determining the year of manufacture of the bottle

The industrial manufacturing process of glass from sand has changed over the centuries. These changes give changes in the chemical composition of glass of wine bottles. Today, these changes concern impurities in the glass due to the use of recycled bottles in glass factories. As these changes are continuous and uncontrolled, we can say that each bottle has own chemical fingerprint which allows identifying it. We use a high energy ion beam delivered by a particle accelerator to create X-rays emitted by atoms of the glass. These X-rays are analysed and give the chemical composition of the glass. Previous studies of many certified bottles allow building a data-base containing now around five hundreds references.

-III- Sealing

In addition, a certificate of analysis is established with a seal number to make a unique proof of authenticity controllable at any time. A seal covering both the glass and the cap is used to certify the bottle which has been analysed.

 

PDF - 148.1 kb
Fine wine expertise