Evaluation of the Influence of Antifoam Products on Yeast, Tank Cleaning and the Chemical/Physical Properties of Beer
Although foam in the finished beer is an important quality characteristic, foam formation during the manufacturing process can lead to a variety of problems, such as the fouling of machine parts and the losses of valuable compounds in the beer. In addition to numerous methods for processing, technological application of antifoam products can help to control foam formation or to reduce it. Therefore, the focus of this research was to test an antifoam product based on silicone, as well as two hop-based products and compare them with regard to their effects on various parameters, like cleanability and their effect on the resulting product.
In order to fully prevent the formation of foam, the conventional dosage, in which the complete amount of antifoam is being added at the beginning of primary fermentation, was in this case 6 g/hl for the silicone-based antifoam product, 5 g/hl for one-, or 25 g/hl for the other of the hop-based products, given a surface area to total volume ratio of 2:1. The height of the foam varies with the surface area to volume ratio, making it possible to identify approximate linear dependencies according to the product applied. A study of the most efficient methods for adding antifoam products showed that the hop-based products should be added in the conventional manner by dispersing them homogenously throughout the wort, ideally before the fermentation starts. Better results were obtained for silicone-based compounds by wetting the tank walls with the product before transferring the wort to the tank. Moreover the trials on a pilot scale have demonstrated that up to 20 % less fouling on the inner surface of the fermentation vessel is achievable because of utilization of antifoam products. As shown in this research, the fermentation performances could not clearly be differenciated. Application of an antifoam product resulted in a more rapid fermentation on a two-liter scale. Nevertheless, it was found that the application of the antifoam products had no significant negative influence on the sensory characteristics of the unfiltered beer. It is essential that the deviations in foam stability observed in the unfiltered products be closely examined in the future. The same applies to the slight change in the surface charge and the extended lag-time of the harvested yeast.
BrewingScience - Monatsschrift für Brauwissenschaft, 67 (March/April 2014), pp. 48-59
