Efficient treatment methods for higher alpha acid yields

GEA Brewery Systems GmbH has developed a method for the efficient use of hop extract. For an industrial application of this method they also integrated a homogenizer of their affiliated company GEA Niro Soavi. Such homogenizers are well known and proven e.g. in the field of milk treatment.

The process equipment is primarily designed for the use of hop extract, but with a slight modification of the process a mixture of hop pellets and hop extract can also be processed. For the method as well as for the equipment a patent application was filed.

The basic technical principles for higher alpha acid yields are the droplet size reduction in the hop extract suspension and the isomerization of the suspension at 130 °C under controlled process conditions parallel to the usual wort boiling. According to the Provisional Beer Law for the dosing of hop extracts, dosing of the isomerized hop extract suspension can be done towards the end of wort boiling in the kettle or independently of this provision directly before the wort cooler into the hot wort.

Impressive results

Results of large-scale trials with a reduction of alpha acid dosing by 30 percent showed a sensorially more intense, but more harmonious bitterness in the beer than in the beer batch that was produced in the standard way with dosing of the total hop extract into the wort kettle. The analytical results of the bitterness units showed a comparable level in both beers. The indicator substance for the hop oil content, linalool, is significantly higher by a factor of 3-5 in beers with dosing of isomerized hop extract suspension than in the normally hopped beer.

If it is possible to brew beer outside the provisions of the Provisional Beer Law, the yield of isomerized alpha acids can be increased even further by the process-related adjustment of the pH-value in the hop extract suspension according to the Drinking Water Ordinance.