Beer Testing
Technology Helping to Simplify the Essential Process of Beer Testing
Those devoted to the product of the noble art of brewing are likely to claim that the only form of beer testing necessary is to taste it. In practice, however, taste alone is far from being the only quality considered to be important by those specialists who are directly involved in the production of an acceptable and, if possible, exceptional brew. In addition to the somewhat arbitrary standards applied by the consumer, the production of alcoholic beverages is subject to in-house quality control standards, as well as to specific government legislation with which brewers, winemakers, and distillers are obliged to comply.
A typical programme of beer testing should be designed to address potential problems at each stage in the brewing process. It should therefore begin with steps to ensure the quality of the raw ingredients, such as malted barley, yeast, and hops. During this phase, the main thing to be on the alert for is the presence of mycotoxins and/or pesticide residues in the malt and hops. If excluded at this stage, they cannot find their way into the final products. In addition, both the viability of the yeast and its freedom from contaminating strains will need to be confirmed to ensure efficient fermentation.
With these aspects covered, the focus of the beer testing programme will now need to be directed at the condition of the finished product. As well as performing repeat tests for the possible presence of any mycotoxins or pesticide residues, there are four main qualities of the brew that will need to be assessed. These are its colour, its alcohol content by volume or ABV, its pH level, and its degree of bitterness. All four of these factors can contribute in part to the taste and to the overall acceptability of the brew, while an accurate determination of the alcohol content, which must then be displayed on the label, has long been a legal requirement.
Colour, like taste, is an aspect of beer testing that is somewhat subjective. Not surprisingly then, the use of a photometer to compare the test samples with the colour of a series of standardised preparations ensures that more accurate measurements are possible, and will provide the most effective means with which to avoid any possible subjectivity. To determine the alcohol content, nothing more sophisticated than a hydrometer to measure the specific gravity, before and following the fermentation process, plus familiarity with a numerical constant and a simple formula to calculate the ABV is needed.
Measuring the pH is an important component of beer testing, for which both pH test strips and compact meters are available. The desired figure varies according to the brew. For instance, while a range of 4,0 to 4,5 is typical of good ale, lagers are at their best when their pH lies between 4,4 and 4,7.
Finally, measuring its bitterness is perhaps the most exacting aspect of a brewer’s quality control programme. Fermentation results in the production of sugars, so the resulting sweetness needs to be countered. The degree to which this is successful depends upon the concentration of iso-alpha acids present, which can be measured using solvent extraction followed by a spectrophotometric assay.
IEPSA is a leading supplier of analytical equipment and test kits to South Africa’s food and beverage industry.
