Wine bottle colour and oxidative spoilage

There is environmental pressure on the wine industry to reduce the mass of glass bottles as well as to move away from darker coloured bottles to either ‘flint’ or ‘amber’ colours. It is argued that this contribution would ultimately lower energy and recycling costs and at least partially address current issues of sustainability, emissions, energy, packaging and resources. While these arguments are substantially valid, changing the colour and mass of wine bottles tends to be dictated by aesthetics and consumer appeal. The advent of lighter weighted bottles has addressed issues relating to reduced carbon emissions through lower energy costs of transport. However, there is a lack of information regarding the stability of wine in glass bottles that are thinner and lighter coloured than their traditional counterparts. The combination of lighter and/or thinner bottles may offer less light protection and have potential major implications for wine stability. The impact of elevated temperatures to which wine may be subjected during transport and storage, as well as the combination of light, temperature and residual oxygen content from bottling, on wine stability has not been investigated in detail previously.

This pilot project was designed to examine the influence of light, temperature, glass transmission (colour and bottle thickness) which impacts on the development of pigmentation or enhanced colour of white wine. Particular focus was made on the relationship between the wavelength of radiation necessary for the photo-activation process and glass transmissivity. In addition to these environmental variables, the link between various wine components (type of phenolic compound, iron(III) tartrate, riboflavin and molecular oxygen) was also investigated.