Definition of quality classes for champagne cork stoppers in the high quality range

Summary

 For champagne and other sparkling wines, agglomerated cork stoppers are used, lined at the bottom with two superposed discs of natural cork. The quality evaluation of champagne stoppers in the high quality range was made in relation to the porosity of the visible surface of the bottom cork disc using image analysis techniques. The average porosity coefficient was 3.1%. Most pores were small but approx. 75% of the total porosity comes from pores with an area >0.25 mm². Pores with a high visual impact (>2.0 mm²) are less than 1% and were not determinant to the total porosity. The quality grading could be made using porosity coefficients as selection criteria to discriminate between classes. In comparison to commercial grading, the use of quantified porosity parameters for quality class definition allowed higher within class homogeneity and between class differentiation.