PRODUCTION OF BEER Beer is an alcoholic beverage made from malted grains, hops, yeast and water. The grain is usually barley or wheat. Fruits, herbs and spices may also be used for special styles. The word BEER is derived from the Latin word BIBERE that means to drink. There are different types of beers which are produced by various methods by using different raw materials. BARLEY BEERS Beer is brewing from barley grains. Types of Barley beers: Barley beers can be divided into two types. Those are 1. Bottom fermented beers 2. Top fermented beers Bottom fermented beers: These are also known as Lager beers because they were stored or lagered in cold cellars after fermentation for clarification and maturation. Bottom fermentation is a slow alcoholic fermentation process. Here Yeast collects bottom fermenting liquid. It is carried out at low temperatures. Yeasts used in bottom fermented beers are strains of Saccharomyces uvaram. Several types of lager beers are known. They are Pilsener, Dortmund and Munich. Pilsener: this is a pale beer with a hop taste. Its alcohol content is 3 to 3.8% by weight. Its lagering time is 2-3 months. The brewing water is soft and it contains little Calcium and Magnesium ions. Dortmund: This is a pale beer, but contains fewer hops. It has more body (i.e. it is thicker) and aroma. The alcohol content is also 3-3.8%. The PRODUCTION OF BEER Page 1
lagering time is 3-4 months. The brewing water is hard, containing large amounts of Carbonates, Sulfates and Chlorides. Munich: This beer is dark, aromatic and full bodied beer with a slightly sweet taste. It is slightly hopped. The alcohol content is 2-5%. The brewing water is hard and contains Carbonates. Top fermented beers: Top fermented beers are brewed with strains of Saccharomyces cerevisiae. Top fermentation is a violent process. Yeast use top fermented liquid. It is carried out at high temperatures. Ale: It is a pale, highly hopped beer with an alocoholic content of 4-5%. It is very bitter and has a sharp acid and an aroma of wine ecause of its high ester content. Mild ale is sweeter because it is less strongly hopped than the standard pale ale. Porter: This is a dark brown, heavy bodied and strongly foaming beer produced from dark malts. It contains less hops and is sweeter. It has an alcohol content of about 5%. Stout: Stout is a very dark and highly hopped beer with a strong malt aroma. The alcohol content is 5-6.5%. The lagering time is 6 months. PRODUCTION OF BEER Page 2
RAW MATERIALS Malted barley, hops, adjuncts, yeast and water are used as raw materials in brewing. Barley malt: This is the base ingredient of the beer. It provides sugars, soluble starch and enzymes, which are necessary for the fermentation. Advatages of Barley: Two distinct barley types are known. One with six rows of fertile kernel and the other with two rows of fertile kernel. The six row varieties are richer in proteins and enzyme content than the two row varieties. This is one of the reasons why adjuncts are so widely used in breweries. Its husks are thick, difficult to crush and adhere to the kernel. The thick husk is the protection layer against fungal attack during storage. The gelatinization temperature is 52-59 C much lower than the optimum temperature of α- amylase (70 C) as well as β- amylase (65 C) of the barley malt. Adjucts: Hops: These are used when the malt lacks in proteins, starch and sugars. These are added to the malt only for additional proteins, starch and sugars, but not have an essential part in brewing. These can increase the alcohol content and shelf life of the beer. They are very cheaper than malt. They do not play much part in imparting aroma, colour or taste. Hops are the dried cone shaped female flower of hop plant Humulus lupulus. It is a temperate climate crop. It is botanically related to the genus Cannabis. PRODUCTION OF BEER Page 3
The importance of hops in brewing lies in its resins which provide the precursors of the bitter principles in beer and the essential oils which provode the hop aroma. Effects of hops: It replaces the flat taste of unhopped beer with characteristic bitterness and pleasant aroma of hops. Hops have antimicrobial effects especially against beer Sarcina (Pediococcus damnosur) and other beer spoiling bacteria. Due to the colloidal nature of the bitter substances they contribute to the body, colloidal stability and foam head retention of the beer. Tannins of the hops help in the precipitation of the proteins during the boiling of the wort. Water: The mineral and ionic content and ph of the water have profound effecys on the type of beer produced. Some ions are undesirable in brewing water: a. Nitrates: Slow down the fermentation b. Iron: Destroys the colloidal stability of the beer. Some ions are desirable in brewing water: a. Calcium: Lead to better flavour. b. Carbonates: Tend to increase the ph. The ph of the water controls : a. Enzyme systems in malt. b. The degree of extraction of soluble materials from the malt. c. The solution of tannins and other colouring components. d. Isomerization rate of hop humulone. e. The stability of the beer itself and the foam on it. PRODUCTION OF BEER Page 4
Brewer s yeasts: Yeasts in general produce alcohol from sugars under anaerobic conditions, but not all yeasts are necessarily suitable for brewing. Brewing yeasts are able, besides producing alcohol, to produce from wort sugars and proteins a balanced proportion of the esters, acids, higher alcohols and ketones which contribute to the peculiar flavour of beer. Mainly Saccharomyces strains use in the production of Barley beers. S. cerevisiae S. uvaram Occurs singly or in pairs Capable of fermenting only the fructose moiety and it lacks the enzyme system needed to ferment melibiose which is formed from galactose and glucose. This is the most diagnostic distinction. More sporulation These strains have a stronger respiratory Usually forms Chains and occationally Cross chains Able to ferment the trisaccharide, raffinose made up of galactose, glucose and fructose. Less sporulation Weaker respiratory PRODUCTION OF BEER Page 5
BREWERY PROCESS This process involved in the conversion of barley malt to beer. It may be divided into the following steps: 1. Malting 2. Mashing 3. Fermentation 4. Storage 5. Packaging 1. MALTING Malting serves the purpose of converting insoluble starch to soluble starch, simplifying proteins, generating nutrients for yeast and the development of amylases and proteases enzymes in the grain. In other words, malting is the process of modifying the grain in order to make the sugars trapped inside the kernel available for mashing. The three main steps of the malting process are steeping, germination, and kilning. Steeping: The purpose of steeping is to hydrate the grain. Steeping will raise the moisture content of the grain from approximately12% to 45% which will help in the promotion of germination. Microorganisms grow in the steep in order not to allow grain deterioration. The steeping process typically takes 2-3 days. PRODUCTION OF BEER Page 6
Picture 1& 2 show the steeping tanks in beer industry. Germination: The grains are then transferred from a malting floor Germinating grain must be aerated Maximize the enzyme production and minimize the enzyme activity and plant growth for controlled germination. Sometimes use the plant hormone to short the germination time. PRODUCTION OF BEER Page 7
Picture 3: Malt is coming from steeping tanks Picture 4: Aerating hydrated grains on germination beds Picture 5: germinating on germination beds Kilning: Dry the grains at mild temperature until the moisture content is reduced from about 40% to about 6%. The temp of heating depends on the type of beer to be produced. PRODUCTION OF BEER Page 8
Picture 6: Aerated grains are kilning by Circular kiln. MALT ANALYSIS There are some critical points which affects the desired qualities of beer. Those are 1. Colour: It should not vary from batch to batch. 2. Moisture: Moisture content over 6% is unacceptable. 3. Diastatic Power: This is the strength of the starch reducing enzymes in malt. 4. Protein (Total): It is very important for the growth of yeast. 5. Kernel Size: Plump kernels are easier to mill than thin kernels. PRODUCTION OF BEER Page 9
2. MASHING This step is Central part of brewing. The purpose of this step is to Extract the soluble portion of the malt and to enzymatic ally hydrolyze insoluble portions of the malt. Starch and proteins are large components in the dry weight of the grain. The controlled breakdown of the starch and proteins has tremendous influence on beer character. α and β-amylases breakdown the starch and temperature and ph must be maintained below optimum range for the perfect enzyme activity. Enzyme Optimum temp Optimum ph α amylase 70 C 5.8 β- amylase 60 65 C 5.4 Proteases breakdown proteins through peptones to polypeptides and then polypeptides into aminoacids. It determines the nature of the wort, the nutrients available to the yeasts and the type of beer. Mashing determines: The nature of the Wort The nature of the nutrients available to the yeasts The type of beer produced The aqueous solution resulting from mashing is known as Wort. Picture 7: Mixing adjuncts and hops during the Mashing. PRODUCTION OF BEER Page 10
Picture 8: Mash, which consists barley malt, additional ingredients and wort. Picture 9: Filtering the Mash for the Wort separation. Picture 10: Sweet wort, after Filtration of Mash. PRODUCTION OF BEER Page 11
WORT BOILING Wort is boiled for 60-90 min in a brew kettle. The purpose of boiling: To concentrate the wort, this loses 5-8% of its volume by evaporation during the boiling. To sterilize the wort to reduce its microbial load before its introduction into the fermentor. To inactivate enzymes so that no change occurs in the composition of the wort. To extract soluble materials from the hops, which not only aid in protein removal, but also in introducing the bitterness of hops. To precipitate proteins, which forms flocs because of heat denaturation and complexing with tannins. To develop colour. Removal of volatile compounds such as fatty acids which could lead to rancidity in the beer. Picture 11: wort boiling Kettle. PRODUCTION OF BEER Page 12
PRE FERMENTATION TREATMENT OF WORT: The hot wort is not sent to the fermentation tanks. Then the wort is separated by Centrifugation. The separated wort is then cooled in a heat exchanger. The cooled wort is now ready for fermentation. Now it does not have any enzymes but it is a rich medium for fermentation. 3. FERMENTATION The cooled wort is pumped into fermentation tanks and yeast is innoculated. Yeast convert the glucose into ethanol and carbon dioxyde through fermentation. C 6 H 12 O 6 + 2 PO 4-3 + 2ADP 2 C 2 H 5 OH + 2CO 2 + 2ATP The carbon dioxide is allowed to vent out through these blow-off hoses Picture 12: Fermentation Tanks. PRODUCTION OF BEER Page 13
Picture 13: Adding Yeast to the fermentation tank. Picture 14: Blow- off hoses on fermentation tanks. 4. STORAGE At the end of the primary fermentation, Green beer is produced, which is harsh and bitter and has yeasty taste. Then the beer is stored in closed vats at a low temp for 6-9 months Lagering gives final desirable qualities to the beer. 5. PACKAGING Beer is transferred to pressure tanks. It must not contact with the oxygen during the distribution. Bottles are thoroughly washed with hot water and Sodium hydroxide before being filled. The filled and crowned bottles are passed through a pasteurizer. PRODUCTION OF BEER Page 14