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Excell L’EXPERTISE ANALYTIQUE (Analytical Expertise)
Floirac, June 20, 2024.
Supplement to Analysis Reports
Part 1: Analysis of Oxidant Residues
Context: The TEDEM cooperage has worked on an innovative process for cask regeneration. Since this process involves oxidation stages in order to eliminate, notably, color staining resulting from previous uses of the casks in question, the EXCELL laboratory was requested to perform measurements of oxidant residues. To meet this analytical need, the EXCELL laboratory drew inspiration from the ISO 21128:2006 standard, revised in 2020, which is typically used for cork closures. This standard outlines iodometric titration for the determination of oxidant residues released by ready-to-use cork closures. The standard was therefore well-suited to the objective and was easily applied to the wood matrix.
Results: The figure below illustrates, in the form of a box and whisker plot, the database of all oxidant dosing results performed in the laboratory on all wood samples analyzed in the laboratory (those from TEDEM cooperage and those coming from other laboratory clients).
The graph displays the results of the analysis of oxidant residues. The box and whisker plot shows the following values in meq/g (milliequivalents per gram):
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Document 2: Tannin Analysis - Part 2
(The top of the page continues from the previous document's results)
This illustration shows the obtained average value: 0.28 meq/g and a median value of 0.18 meq/g. To ensure these values are not exceeded (which could foreshadow a risk of oxidation of future wines to be housed in the treated casks), the objective has been set to not exceed 0.15/0.2 meq/g on the casks. The cooperage will, therefore, have to implement a control plan to ensure compliance with this objective.
Part 2: Tannin Analysis
Context: In parallel with the previously mentioned tests, the processes developed by the TEDEM cooperage suggested adding tannins to restore the tannin potential of treated casks. The cooperage used various types of tannins, and the EXCELL laboratory intervened to objectivize the quantity of tannins present in wood treated in this manner. The technique used is an ellagitannin dosing method using HPLC/UV/MS, derived from detailed dosing methods in scientific publications from the ISVV.
Results: Once again, the illustration via a box and whisker plot of all dosings carried out by the laboratory on cooperage wood (new wood and used wood) is used to dimension possible variations and reasonable objectives allowing for verification of a consistent amount of tannins in casks treated according to the TEDEM cooperage process.
The graph shows results of the tannin analysis (likely in mg/kg, as units are not explicitly listed, but the values align with the subsequent document). The box plot indicates:
Document 3: Conclusion on Tannin Analysis
The average value of ellagitannins is 1454 mg eq. ellagic acid/kg of wood.
The graph below specifies the average obtained on wood coming from the TEDEM cooperage process. The average value then obtained is 407 mg eq. ellagic acid/kg of wood. We can indicate that the process brings to the used casks thus treated a tannin potential of about 30% of a new cask, which seems to be a very interesting result in the current context of expectations by consumers of wines that are globally less tannic.
The graph displays the ellagitannin results specifically for the TEDEM process (likely in mg eq. ellagic acid/kg wood). The box plot shows: