Known in the trade as flavoured alcoholic beverages, these new products presented a new challenge for quality control of appearance
Flavoured alcoholic beverages (FABs) are relatively new products in the drinks market that present a challenge for colour control. Coors Brewers is taking advantage of a unique service that enables a quick visual comparison between a drink sample and glass colour standards that represent the extremes of colour acceptability.
Colour control from batch to batch is an important quality characteristic for beverages.
The eye can easily detect differences in colour and, if two bottles of the same drink sitting side by side on a shelf have a noticeable colour difference, then the consumer may judge the product to be of poor quality because of the colour inconsistency.
With this is mind Coors Brewers, producer of Reef exotic alcoholic fruit drinks, has been working with Tintometer to develop a means of controlling colour from batch to batch.
Whereas it is possible to use absorbance values at a single wavelength to measure the colour change of traditional alcoholic drinks such as beer, this is not possible with FABs, which come in a range of bright colours and are often also cloudy.
Coors experimented with tristimulus instruments, but found the colour data obtained to be too complicated for routine QC work, and the cloudiness of the samples provided added complications, making them impractical for measurement by either absorbance or reflectance.
Nor is it possible to rely on stored samples from previous batches, as they are known to fade over time, allowing product colour to drift from the original specifications.
Coors approached Tintometer with the idea of using glass colour standards for colour control, a practice that has been widely used for decades in the visual colour grading of beers.
For each Reef flavour, Tintometer developed a series of five glass colour standards, which were matched to samples representing degrees of colour acceptability: fail/low, acceptable/low, standard, acceptable high, fail/high. The colour standards were mounted in a Lovibond test disc, which slots into a visual comparator instrument for matching against sample colours.
The colour specification of each standard is retained for future use.
The Coors production site uses the comparator and colour standards to check the product in the mix tank prior to packaging and make necessary colour adjustments to bring the product within the acceptable colour range.
The visual colour check is not affected by sample clarity, it is simple to perform and operators can see immediately if a sample differs from the target colour, allowing corrective action to be taken very quickly.
