Abstract: Solute concentration measurement apparatus comprises a container (1) for a solution together with an ultrasonic transmitter (2) and receiver (3). A signal from the transmitter (2) passes through the solution to be detected by the receiver (3). A clock (5) and microprocessor (6) determine the speed of sound in the solution and hence the concentration of solute present.

Abstract: A method of enhancing the bitterness of beer by oxidation of .beta.-acids obtained from a carbon dioxide extract of hops and introducing the resulting hulupone, preferably at least partially purified, into the beer. The extract contains also .alpha.-acids which are isomerized, separated from the .beta.-acids, and introduced into the beer. The result is a high yield of bitterness-producing material for use in the brewing process.

Abstract: A sealing cap for use in sealing the can filling head of can filling apparatus to allow cleaning fluid to be pumped through the head. The sealing cap closes off the head in substitution for a can and comprises a sealing member rotatably mounted within a threaded retaining ring adapted to be screwed onto a threaded outer surface of the can filling head. This configuration allows easy fitment of the sealing cap during head cleaning operations.

Abstract: There is described a method of and apparatus for monitoring the concentration of gas in a liquid. The apparatus includes a semi-permeable diaphragm across the face of which the liquid flows. Gas contained in the liquid permeates through the diaphragm into a chamber and the pressure within the chamber is measured. This pressure is representative of the concentration of gas in the liquid and permits control of the quantity of gas injected. In particular there is described a method and apparatus for monitoring the concentration of two different gases which may be dissolved in a flowing liquid.