A quick answer from my memory on these issues:

I believe the method can only be indicative and interpretation on a case by case basis taking into consideration the type of wine and the oenological practices authorised for a given sparkling wine.

For example Champagne cane sugar is traditionally hence CO2 should have the signature of C4 sugar.

Moreover a large range of 13C isotope ratio can be observed for industrial CO2.

CO2 from organic fossil origin show rather 13C isotope ratio (about -30 to -50 per mil) , but that from mineral carbonate can be above -10 per mil.

Nowadays some industrial CO2 seems also to be recovered from fermentation of various material, for instance grape (wine) , barley (beer) , therefore with a typical C3 isotopic signature.

Unfortunately the 18O isotope ratio is of no help in reason of the isotopic exchange with water, so the 18O/16O isotope ratio of CO2 of sparkling wine does not bring any more information about the source of the gas.

Thanks a lot Claude Guillou ,

In your opinion, if OIV consider that for fermentation of sugar from C3 plants the 13C is in the range of -17‰ to -26‰, but still based on the no-exhaustive knowledge of natural variation, a value for example -36‰ (±1.4‰ as 95% confidence level using a coverage factor of k = 2), and in absence of European reference valued or national values, how we can consider the wine, with or without added industrial CO2?

Do you know if there are countries with specific reference values to be able to declare without doubt the addition of industrial CO2?

The answer is already in the OIV method:

"Gasified wines have their 13C/12C isotope ratio below -29‰ or above -10‰"

That is understood addition of CO2 from organic fossil origin.

I also would like to correct my previous answer CO2 fro mineral carbonate are > -7 per mil ( not -10 as indicated erroneously) .

As memo: the 13 C isotope ration of PDB is (by definition) at 0 per mil and those of other mineral carbonates around zero per mil..

Détermination de l'origine, naturelle ou artificielle, du dioxyde de carbone (CO2) dans des bouteilles d'eaux gazeuses par analyse de la teneur en carbone-13.

• November 2014
• DOI: 10.13140/RG.2.2.11408.43528 Issam Moussa & Delphine PEREIRA
• Summary:
• Isotope control method designed to identify the origin of CO2 in sparkling bottled waters. The method is based on the analysis of the 13C/12C ratio in the dissolved inorganic carbon (DIC) of carbonated bottled water. Natural carbonated natural water has δ13CPDB (DIC) values between -11 and +7. Generally, the industrial carbon dioxide injected into mineral bottled water is produced from hydrocarbons by burning or chemical processing. Hydrocarbons, and their derived CO2, are characterised by a low 13C/12C ratio (-40‰). Thus, a single analysis distinguishes the carbon dioxide in the bottled water (i.e. either from a natural source or added exogenous CO2 of industrial origin). The CO2 can be obtained from other industrial sources, mainly as a by-product of fermentation plants. Nevertheless, the carbon isotope allows detection of the industrial gas injected in most of this cases.Finally, the isotopic composition 13C carbonated mineral waters allowed us to determine the state, natural or artificial, the gas used and concluding on the authenticity of water bottles. The method has two limitations. It does not allow detection of sparkling water reinforced with the original gas from the source, or addition of industrial carbon dioxide produced from marine limestone (δ13C between -2 and 2‰).

Thanks a lot Claude Guillou ,

When I mentioned reference values, I refered to legal (mandatory) reference values. As far as I know the OIV are recommendation based on the current scientific knowledge.

Thanks a lot Issam Moussa

Do you know if there are countries with legal (mandatory) reference values for sparkling wine to detect the addition of industrial CO2 (when it is not allowed to do that)?

If there are these legal values, I wonder if they are exhaustive to cover every natural variation.

Exogenous CO2 in South American sparkling wine

January 2016 BIO Web of Conferences

DOI: 10.1051/bioconf/20160702001

Project: Effect of glutathione addition in sparkling wine

by : Susiane Leonardelli et aL..

Abstract and figures

The sparkling wine production and consumption have increased significantly in the last years. With the increased demand appear the necessity to check the sparkling wine authenticity, because the practice of adding CO2 in sparkling wine is not allow. A way to control the carbonation process is through the determination of CO2 δ13C, because the sugar added during the second fermentation define the CO2 isotopic value, according to elaboration process. For this reason, the aim of this study was to evaluate the relationship between values of δ13C from still wines and sparkling wines, in order to set up limit values to exogenous carbonation control. Thirty-eight still wines elaborated by microvinification and 59 samples of commercial sparkling wines were analyzed, using an isotope ratio mass spectrometer (IRMS). The most negative value of natural δ13C from still wine found was − 24.7‰, it can be to estimate that lowest values are an indicative of industrial CO2 addition. Among the commercial sparkling wine from South America evaluated in this study, 10% from the samples showed signs of carbonation. Through this research was possible to establish limits of isotopic values to determine the presence of exogenous CO2.

I can be wrong but I do not believe that such "legal" values exist.

What is available are ranges indicated in scientiific literatures and in OIV methods.

Legal values have to be adopted by Regulations either by countries or International organisations.

OIV methods are intended for measuring physico-chemical parameters they include some hint for interpretation, but not for legal conclusions which have to be established against authorised enological practices established either by OIV, EU or national level.

Anyway, the -36 per mil indicated in this discussion clearly shows the CO2 is from industrial origin, and this observation is supported byt heis sentence in the OIV method. So then one has to check whether this is compatible with authorised practices where this sparkling wine is produced and/or sold.

The conclusion is a an "expert" conclusion based on , established ananlytical methods, scientific knowledge and recognised professional experience in that field,

Dear Colleague

I think you don't need official values to pronounce on the presence of exogenous CO2!

Indeed, you can use 13C values of internal substances specific to your wine (after extraction)

As for example the values of 13C ethanol or 13C organic acids or sugars ...

The comparison will allow, taking into account the factors of the IF, to pronounce with certainty on the origin of CO2 in your bottle.

Agree with Issam.

Thanks a lot Claude Guillou and Issam Moussa ,

I agree, especially with the hereby statements that summarise well the approach:

“Indeed, you can use 13C values of internal substances specific to your wine (after extraction)

As for example the values of 13C ethanol or 13C organic acids or sugars ...”

“The conclusion is a an "expert" conclusion based on, established analytical methods, scientific knowledge and recognised professional experience in that field”.

However, we need legal values if we want to sanction (meaning money) the not allowed practices, while "expert" conclusions can only trigger further investigation (e.g., inspection on-site in the winery).

I used to supply reference isotopic gases to NIST for CO2 isotopic analysis. There is a wide variability in the ratio from different CO2 sources, and it is NOT an "industrial" vs. "Natural" property! Thus, it's use as a quality parameter for wines is misguided and probably futile. I do not know of ANY "legal" requirement for such a ratio in any application. "Customers" may certainly demand anything that they want. Just be sure that they pay for it!