No abstract

By using a new sensitive method the contents of dimethyl sulphide, dimethyl disulphide and dimethyl trisulphide have been determined in beers and wines, and the contents of these sulphides and diethyl sulphite measured in distilled beverages. The head-space volatiles are swept out from the beverage in a stream of nitrogen and adsorbed in a tube containing porous polymer. The volatiles are desorbed directly onto the column of a gas chromatograph by connecting the tube to the column and sliding the free end of the tube into the hot injection block from the oven side. The sulphursensitive flame photometric detector is used and the peak areas and identifications are collected on cassette and processed by computer to give the content of volatile sulphur compounds directly in Mg/litre beverage. The detection limits are 2 Mg/litre for dimethyl sulphide, 0*1 |ig/litre for dimethyl disulphide and trisulphide, and 5 Mg/litre for diethyl sulphite. The analysis time for each sample is 30 min and the coefficient of variation is 5%.

No abstract

The rise in the cost of energy is a major factor in increasing the costs of such distillery processes as the pre-concentration and drying of stiliage. Most of the stiiiage water (70-80%) that would have to be evaporated can instead be separated and used again for mashing, with only the remaining 30-20% being made up with fresh water. Experiments were performed on both laboratory and production scales. The energy saving resulting from this reduced evaporation of water has been calculated to be 3000 t/a heavy fuel oil in the production of 5000 t/a 100% ethanol in a grain distillery.

A method has been developed for the routine determination of diacetyl and pentanedione in alpoholic beverages. After the addition of internal standard and any necessary dilution, a stream of nitrogen swept the components of the sample at a fixed temperature to a 2 ml injection loop of a gas chromatograph fitted with an electron capture detector. The data from the chromatograph were collected on cassette and processed by computer. The time between starting tempera ture equilibration of the sample and obtaining the diketone content as /ig/litre beverage was about 17 min. The coefficient of variation for diacetyl was 1 -8% (5-1%, with manual injections) and for 2,3 pentanedione 1 6% (91%) for replicated analyses of the same sample.