Agnus - First Czech High-Alpha Hop Variety.

Abstract

In the year 2001, the variety Agnus was registered in the Czech Republic as the first Czech high-alpha variety of hop. It contains approximately 30 % b.w. in dry matter of total resins and 11 to 15 % b.w. of α-bitter acids. The content of β-bitter acids inheres mainly in the range from 5,0 to 7,5 % b.w. in dry substance. In the Agnus variety, the soft resins form approximately 90 % of weight of total resins, the rest remains to hard resins. The content of cohumulone in α-bitter acids is generally higher than 30 % rel. and in maximum values it can even reach the limit of 39 % rel. The content of hop oils in the Agnus variety is high and ranges from 2,0 to 3,0 % b.w. Within the composition of oils, the terpenes myrcene, β-caryophyllene and α-humulene dominate. The content of β-farnesene is very low and as obviously it does not reach 0,50 % rel. The oxygenous fraction of hop oils is rich in esters, a number of esters abounds in homologous series. The content of α-bitter acids in CO2-extracts of the Agnus variety represents 39 till 42 % b.w. The testing of brewing properties of the Agnus variety started in advance in the year 2000 on semipilot and plant scale. The plant brewing tests are effected both in breweries with conventional fermentation and ageing and breweries using the fermentation technology in cylindroconical tanks. The brewing tests have so far taken place in five breweries (where large, medium and small breweries were represented) and they go further on. The present results show that, by the mean of quality, the hop products from the Agnus variety can fully replace similar products from foreign varieties, imported so far for needs of local breweries.In the year 2001, the variety Agnus was registered in the Czech Republic as the first Czech high-alpha variety of hop. It contains approximately 30 % b.w. in dry matter of total resins and 11 to 15 % b.w. of α-bitter acids. The content of β-bitter acids inheres mainly in the range from 5,0 to 7,5 % b.w. in dry substance. In the Agnus variety, the soft resins form approximately 90 % of weight of total resins, the rest remains to hard resins. The content of cohumulone in α-bitter acids is generally higher than 30 % rel. and in maximum values it can even reach the limit of 39 % rel. The content of hop oils in the Agnus variety is high and ranges from 2,0 to 3,0 % b.w. Within the composition of oils, the terpenes myrcene, β-caryophyllene and α-humulene dominate. The content of β-farnesene is very low and as obviously it does not reach 0,50 % rel. The oxygenous fraction of hop oils is rich in esters, a number of esters abounds in homologous series. The content of α-bitter acids in CO2-extracts of the Agnus variety represents 39 till 42 % b.w. The testing of brewing properties of the Agnus variety started in advance in the year 2000 on semipilot and plant scale. The plant brewing tests are effected both in breweries with conventional fermentation and ageing and breweries using the fermentation technology in cylindroconical tanks. The brewing tests have so far taken place in five breweries (where large, medium and small breweries were represented) and they go further on. The present results show that, by the mean of quality, the hop pro

Keywords

• Hop
• Beer
• hop oils
• bitter acids