The process equipment HOPSTAR® Iso 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 under controlled process conditions parallel to the usual wort boiling. The 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.
Results of large-scale trials with a reduction of alpha acid dosing by 30 % 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.
The described technology supports customers in the brewing industry to achieve the objectives defined by politics regarding the implementation of energy-efficient processes for beer production and contributes to the reduction of CO2 emissions.
Efficient processing for higher yields – Conclusion
The investment in the HOPSTAR® Iso equipment for homogenization and isomerization of hop extract suspension is characterized by the efficient and sustainable use of hops, especially the alpha acids. With a possible reduction of hop dosing by 30 %, every brewer can easily determine how far his annual purchasing costs for hops will be reduced.
In addition, with regard to the energy expenditure during wort boiling, savings of up to 50 % of the originally required heat are possible.
With the use of this technology, the demands for the application of energy-efficient and sustainable production processes to achieve the objectives of environmental policy in the EU are met.