GB1063808A - Concentrated hop, and processes for its preparation - Google Patents

Abstract

Concentrated hop is prepared by deep-cooling hops and subjecting them to the turbulent action of a gas vortex, so as to separate the various components of the hop. Thus, the hops may be reduced in particle size to between 200 and 25,000 microns, cooled to a temperature within the range -1 DEG C. to -35 DEG C. and subjected to a vortex of air or carbon dioxide at a speed greater than 15 metres per second, up to 120 metres per second. The cooling of the hops is effected either in a refrigerator or by evaporating a low boiling-point material, for example liquid or solid carbon dioxide, liquid air, dry ice or liquid nitrogen. There may be employed for the size reduction a pulverizing machine employing a rotating flail which generates vortices by its rotation, a high speed cutting, percussion or jet mill, or a vortex-generating or vortex-supplied sifter, such as a centrifugal sifter equipped with a cylindrical sieve-casing provided with a rotating dish or beater, a bolting cloth or several opposing gas jets. The hop concentrate is sifted in a rotation or vibration sifter or plan-sifter having a mesh width of from 175 to 500 microns to separate the lupulin-rich fine fraction from the lupulin-free coarse fraction. The fine fraction is filled in an inert atmosphere into a light- and air-tight container from which the low boiling-point components of the fine fraction are eliminated by gradual evacuation. The hops are coarsely defoliated prior to cooling. According to an example, kilned hops are cooled to -30 DEG C. and reduced, in a high speed percussion mill supplied with air or inert gas vortices at about 50 metres per second, to a particle size of about 1000 microns. The ground material thus obtained is separated at about -30 DEG C. by a vibration sieve with a mesh-width of 280 microns into a coarse fraction and a lupulin-containing fine fraction. According to other examples (2) cooled hops are broken down by a jet mill supplied with air or inert gas vortices at about 100 metres per second and separated by a vibration sieve, and (3) hops are broken down in a reduction machine with a sieve perforation of 20 mm., are then cooled, and the cooled product is separated in a centrifugal sifter whose vortices are amplified by forcing gaseous carbon dioxide into the sifter.