Fermentation
Brewing

Processes at the Brewery

  1. Milling & Mashing
    Once the malt is taken to the brewery it is milled and mashed. The soluble materials produced during mashing are the ‘extract’ and the solution of soluble materials in water is called the ‘wort’. This mixture is filtered to separate the liquid wort from the non soluble material remaining called the ‘brewers grains’.
  2. Boiling the wort
    The liquid wort is then boiled. As it is boiled the essential flavouring agent of beers, the ‘hops’, is added. The boiling takes place in order to sterilise the wort, precipitate out undesirable proteins, tannins and carbohydrates, inactivate the enzymes that survive mashing, modify remaining proteins (ie more foam active) and allow further browning reactions to occur, concentrate the wort through evaporation, bring out the flavours in the hops, and boil away some undesirable flavours.
  3. Fermentation
    It is believed that sometime between 10,000-15,000 years ago, a Mesopotamian farmer discovered that the water some grain had been soaking in developed a funny taste. The next day he woke having made two discoveries - beer and a hangover!
    Then, in Sumaria around 6,000 years ago, bread changed from the dry tough stuff that could break teeth to wonderful, light, tasty loaves. The secret ingredient for both the brewing of beer and bread that rises is yeast, a minute fungus required for the fermentation process. Fermentation is the process of conversion of sugars in the form of grapes / other plant material or grains, into alcohol and carbon dioxide. Sugars and starches from fruit (eg grapes) and grains (eg barley) are firstly broken down to mono, di or tri-saccharides and then fermented into ethanol and carbon dioxide. Glucose (a monosaccharide) is the simplest sugar and its conversion can be expressed as follows:

Fermentation is exothermic and is usually conducted under carefully controlled temperature conditions.

In the production of beer, the speed of sugar conversion during fermentation is influenced by the properties of the wort, the temperature (increasing with higher temperatures), the amount and strain of yeast, the pressure and the amount of movement (stirring and the release of CO2 improves the contact between the cells and wort resulting in more vigorous fermentation). Once fermentation has taken place the liquid is usually chilled, filtered and carbonated with carbon dioxide prior to bottling.

Wines are produced as still or sparkling wines. When fermentation continues after the bottle is sealed, additional carbon dioxide will be dissolved in the wine. This is how sparkling wines like champagne are produced.