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Bioflavouring of low alcoholic beer by dry hopping
Dušánek, Václav ; Mikulíková, Renata (referee) ; Pořízka, Jaromír (advisor)
This bachelor thesis deals with the influence of cold hopping of low-alcohol beers on analytical properties and sensory profile of beer. The effect of cold hopping was observed using the varieties Kazbek, Jazz, Mimosa and Uran. In the experimental part, the production process of low-alcohol beer using immobilized yeast is described. After the main fermentation, the low-alcohol beer was kegged into five cuvettes and after 20 days cold-hopped at a dose of 3 g/l with individual varieties. The effect of cold hopping with individual varieties on the organoleptic properties of the beer was observed. Bitterness was determined, with cold-hopped beers showing an increase between 17-24 % in bitterness. Furthermore, the ethanol content was determined by high-performance liquid chromatography at 2,14 % vol. A significant increase in all volatiles, in particular -myrcene and linalool, was found in the cold-hopped beers by gas chromatography with mass spectrometry. The sensory analysis showed that the cold hopping had a positive effect on the overall impression and masked the taste defects of the reference low-alcohol beer. The best hop evaluated for the use of the cold hopping method was the Kazbek variety. The Jazz and Mimosa varieties were also perceived relatively positively by the evaluators. On the other hand, the Uran variety achieved a worse overall impression than the reference beer.
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