The Continuous Brewing of Beer
THE CONTINUOUS BREWING OF BEER
Beer is produced commercially by the controlled fermentation of wort, a liquid rich in sugars, nitrogenous compounds, sulphur compounds and trace elements extracted from malted barley. Fermentation is the process by which glucose is converted to ethanol and carbon dioxide and is expressed chemically as: C6H12O6 + 2PO43- + 2ADP → 2C2H5OH + 2CO2 + 2ATP Behind this simplified chemical reaction is a series of complex biochemical reactions. These reactions (known as the ‘Glycolytic pathway’ or ‘Embden-Myerhof-Parnas pathway’) involve a number of enzymes and the reactions take place anaerobically inside the cells of brewing yeast. DB Breweries carry out this fermentation by a continuous process in which the beer moves through a series of stirred vessels for a period of 40 to 120 hours. After the ethanol has formed the beer is transferred to maturation vessels the flavour is naturally refined. Following this the product is developed into a variety of different brands. Breweries across the world generally use the system of batch fermentation to produce beer, it is the writer’s belief that at this time, only DB Breweries in New Zealand is successfully using continuous fermentation to produce full strength beers. INTRODUCTION Brewing has been mentioned in history as early as Egyptian times and has continued on to the present day with relatively few changes to the basic recipe. Malted barley is the main ingredient, which, when milled and heated in water to extract its nutrients, provides a nourishing sugar- and protein-rich solution named wort (pronounced wert), an ideal medium in which yeast may grow and ferment. In comparatively recent times hops were added to the boiling wort as it was discovered that hops had anti-bacterial properties which preserved the wort and fermented beer and which gave the beer a refreshing bitter taste. For many years the only known method of fermenting beer was a slow batch fermentation process carried out in a
Beer is produced commercially by the controlled fermentation of wort, a liquid rich in sugars, nitrogenous compounds, sulphur compounds and trace elements extracted from malted barley. Fermentation is the process by which glucose is converted to ethanol and carbon dioxide and is expressed chemically as: C6H12O6 + 2PO43- + 2ADP → 2C2H5OH + 2CO2 + 2ATP Behind this simplified chemical reaction is a series of complex biochemical reactions. These reactions (known as the ‘Glycolytic pathway’ or ‘Embden-Myerhof-Parnas pathway’) involve a number of enzymes and the reactions take place anaerobically inside the cells of brewing yeast. DB Breweries carry out this fermentation by a continuous process in which the beer moves through a series of stirred vessels for a period of 40 to 120 hours. After the ethanol has formed the beer is transferred to maturation vessels the flavour is naturally refined. Following this the product is developed into a variety of different brands. Breweries across the world generally use the system of batch fermentation to produce beer, it is the writer’s belief that at this time, only DB Breweries in New Zealand is successfully using continuous fermentation to produce full strength beers. INTRODUCTION Brewing has been mentioned in history as early as Egyptian times and has continued on to the present day with relatively few changes to the basic recipe. Malted barley is the main ingredient, which, when milled and heated in water to extract its nutrients, provides a nourishing sugar- and protein-rich solution named wort (pronounced wert), an ideal medium in which yeast may grow and ferment. In comparatively recent times hops were added to the boiling wort as it was discovered that hops had anti-bacterial properties which preserved the wort and fermented beer and which gave the beer a refreshing bitter taste. For many years the only known method of fermenting beer was a slow batch fermentation process carried out in a