Casey's Beer

Beer is brewed from four basic ingredients: water, malted barley, hops and yeast. Other ingredients can be used for special flavours; mostly they are used for economy.

Water is the main ingredient in beer, its quality is crucial. Brewing water should be physically clean and free of microbes. The mineral character of brewing water is also important. Traditional beer styles evolved to make the best use the local water. Most of the traditional brewing centres in Europe have fairly hard water – Pilsen is an exception. Water with calcium, sulphate, and chloride makes good beer.

Malted barley gives beer its basic flavours and provides the sugars for the yeast to ferment. Barley is a cereal, like wheat. It is malted by first soaking the grain in water, removing the water and then leaving the seed to germinate. Lastly, the sprouted grains are gently kilned. The whole process takes 5 to 7 days. The duration and temperature of each of these steps can be varied to produce different types of malt.

Hops are used to give beer bitterness, hop flavour and hop aroma. There are many varieties of hop, each with its own varietal flavour and aroma. Hops are the female reproductive organs, cones, of the hop vine, humulus lupus. Hop vines are perennial and are grown on trellises about 6 metres high. Typically only female vines are cultivated, they are propagated from rhizomes. Hops contain aromatic resins and oils. Hop bitterness comes from a number of compounds known collectively as alpha acids. Alpha acid contents typically range 2% to 12% depending on the variety and growing season. Generally hops with fine flavour and aroma have lower alpha acid contents.

Yeast is often the forgotten ingredient in beer. Over half the flavour compounds in beer are produced by yeast. Yeast are single cell funguses. In the absence of oxygen, yeast can get energy from glucose by fermenting it. (In the absence of oxygen you and I will die because the cells in our bodies cannot burn glucose to get energy.) The main waste products of fermentation are carbon dioxide and alcohol. The yeast also produce many metabolic by-products. Some of these metabolic by-products will be good for beer taste and flavour, others will be detrimental. Control of fermentation reduces unwanted by-products and their detrimental tastes and flavours. Typical fermentation times in a commercial brewery are about 5 days for ales, and 7 to 10 days for lagers.

Energy should be regarded as the fifth ingredient of beer. Brewing has considerable energy demands for both heating and cooling.