The use of nitrogen as a process gas, foam enhancer and flavour modifier has come to the fore over the last 10 years, with dissolved gas specifications becoming more stringent. Increasingly, marketing and consumer requirements for a targeted product identity or image have to be met, not only for taste but, perhaps equally as importantly for the consumer, presentation. This has resulted in dissolved gases playing a major role in the characteristics of a beer.
Furthermore, the gas content of the product on leaving the brewery (and at dispense) is more tightly controlled to avoid wastage due either to fobbing or to flat beer.
This review concentrates on practical methods for gas control in the brewery and how gas content can be measured.
Gas in Brewing Nitrogen has been in use in the brewery for over 50 years. In the 1 940’s, Guinness used air to top pressure their cask stout which resulted in some nitrogen dissolution, giving improvements in beer presentation. Subsequently in the 1 950’s and 60’s pure nitrogen was used as o top-pressure gas.
Since this initial discovery the use of nitrogen in dispense has gained pace, through the early days of mixed gas dispense in the 1 950’s and 60’s to its current use with lagers, ales and stouts, both for dispense in-trade end in small package for the take-home market. Nitrogen was also used in the brewery as a process gas and not only ¡o the nitrogenotion of stouts but for deoxygenation of dilution liquor from the mid-1960’s onwards. Ihe advantages of nitrogen over carbon dioxide as a process gas ore discussed.
The highest profile development accompanying the use of nitrogen in small pack in recent years has been the so called widget, which has been the subject of a Review in this series. The market share of widget products, which now embraces bottled as well as conned beer, has grown at a remarkable rote.
In 1994 widget beers accounted for 13% of the U.K. take home market, and with canned beer sales rising at 6-10% per year, the widgeted beer volume Looks set for increase further. One particular brand sow a five-fold increase in sales after a widget was introduced.