Brewing: Historical Background, Raw Materials, and Main Steps

1. BREWING

2. Historical background : Producedat Mesopotamia and Egypt about 6000 years ago. Beer is originated from Latin word bibere ( to drink). Spanish word for beer is cerveza. It is originated from cerevisiae; which combines latin words of ceres ( goodness of grain ) and vis (vigor ). Major brewing centers are Pilsen (Czechoslovakia ), Munich and Dortmund ( Germany), Burton-on-Trent (England), Dublin (Ireland), and Milwaukee ( USA).

3. Raw Materials A-Barley : tough husk ( protection for kernel during handling and germination ). It contributes to characteristic flavor of the beer. Malting: produces amylases, proteases and other enzymes which partially degrade starch, proteins and some type of cellulose . Barley: 10-12 % protein, 2 % fat, 58-60 % starch, 6 % fiber, 2.5-3 % ash and 10-14 % husk.

4. B- Adjuncts :nonbarley cereal substitutes. Protein / carbohydrate ratio,% alcohol: gives characteristics of the beer. American malts has higher protein content and enzymatic activity and thicker husk than Europian malts. adjunctare used to adjust properties of malt. beers produced with adjuncts had lower protein content for a given alcohol content, resulting in better physical stability with a lighter character.

5. Common adjuncts are; Raw cereal grains ( milled barley, wheat, rye, and Triticale ) Cooked intact cereal grains Grits :uncooked, nearly pure fragments of starchy endosperm from cereal grains. Maize grits:most common in the USA.

6. Flaked cereals :produced by cooking whole grains then passed through feed rolls to flaking rolls. ( contain little soluble nitrogen, so used as a wort nitrogen diluent.) Flours( wheat and barley, hammer-milled ) Syrups (Sucrose, and its hydrolysis product, inverted sugar) Malt extracts and wort-replacement syrups:expensive.

7. C- Hops : The characteristic aroma and bitterness imparted to beer by the oils and resins of hops make beer and similar malt beverages quite unique. Hops also contribute to microbiological stability during beer processing. Cannabinceae (family name) Cannabis(genera)ie Cannabis saliva(marihuana, hashish) Humulus ( genera ) H. lupulus ( dried fruit or flower the female hop plant) around 85% of all hop products used are either extracts (45%) or pelleted hops (40%). The remaining:unprocessed hop cones

8. D- Water : Requirement: no taints or hazardous components (by charcoal filtration and ultrafiltration.) Calcium and bicarbonate ions affects pH calcium promotes the flocculation of yeast PH affects:enzyme activity, malt yield, solution of tannin, coloring pigments, precipitation of proteins in the kettle, rate of browning reactions, isomerisation rate of humulone and physical and foam stability of beer.

9. E-Yeast : Top fermentation:( 18-22 C )( ales type, German type beer ) S. cerevisiae: it rise to the top of the fermentor at the completion of fermentation ( loose,low density lumps of cells that are adsorbed on to CO2 bubbles and are carried to the surface of the wort.) English pale ale ( bitter): maltkilned to high-temperature to impart a copper color. higher levels of flavor volatiles such as esters, affording fruity characteristics Contains approximately 6 % alcohol .

10. Bottom fermentation : ( 7-15 C)( lagers type, English, American type beer) Saccharomyces pastorianus(formerly called Saccharomyces carlsbergensis) it flocculate and settles down to the bottom of the fermentor at the completion of fermentation . Contains approximately 3.5-4 % alcohol.

12. MAIN STEPS of BREWING

13. 1-Malting: grains are intentionally germinated and dried. the enzyme systems: developed proteins and carbohydrates: modified or made soluble kilning process: color and flavor ingredients are developed and the moisture content is lowered to allow storage of the malted barley. a)-Cleaning and Grading : A, B, C ( where A is the largest in size ). A and B types are used to produce malt.

14. b)-Steeping : Barley is immersed in to water ( 10-15 C)mc reaches to 44-45 % and steep water should be changed every 10-15 hours. Air is injected for mixing and respiration. dormant embryos become activated. high (%) chit count.

15. (a) Cylindroconical steep vessels. (b) Close view of a steeping vessel.

16. c)-Germination : Steeped barley: transferred to germination vessels ( as slurry or by dry transfer). In the past, germination was carried out by spreading the steeped grain on the floor During this period the endosperm serves as a nutrient source for the embryo growth. Embryo synthesis giberrilic acid, which diffuses into aleurone layer. Various hydrolytic enzymes are synthesized by the aleurone cells. These enzymes diffuse into endosperm and break down hemicellulose the protein , peptides, lipids and some of the starch.

17. -amylase is formed during germination. Existing -amylase ( bound to albumin proteins) is being released by the proteolytic enzymes and activated. completed in 5 days at a temperature of 15-21 C. Supply air toprevent accumulation of CO2. Germinated malt: called as “ green malt”

18. Cross-section of a drum used for germination using the pneumatic system. Steeped grain spread on the floor for germination

19. View of a Saladin box typically used for germination using the pneumatic system

20. Grains resting on perforated plates used in the pneumatic system of germination Grains resting on perforated plates automatically turned by rakes

21. The cells walls of the starchy endosperm are degraded during germination.

22. d)- Kilning: Green malt: 40%mc and is dried to 4–5%( in 24 h ) AIMS: Terminates respiration Stops enzymatic activity Prevents microbial spoilage Preserves enzymes for mashing Develops flavor compounds (Maillard browning ) milled for brewing or stored whole in cool dry conditions for up to 12 months e)- Storage of malt: milled to reduce particle size for increasing extraction rate in mashing.

23. layout that will take accountof hygiene and energy efficiency. Tower maltings.

24. The higher temperatures in kilning; a stronger malty flavor a deeper color, reduce enzyme levels, more unfermentable dextrins greater body in the final beer. Pale Malt • Little flavor development • Great enzymatic activity • Dark (Crystal) Malt: less amylolytic (or diastatic) activity, less sugar substrates from starch, and less ethanol produced • Great flavor development (& color)  Dark Beer • Kiln @ 66-72 °C, 2-3 hours • Kiln off @ 121 °C

25. 2-Mashing:(in mash tun ) - adjuncts are milled and cooked in adjunct cooker. 10 % of the malt is added to help liquefaction of starch). boiled for 1.5 hr (2.5-3.5 kg water / kg adjunct ) and starch is gelatinized which makes the starch susceptible to enzymatic action.

26. Adjunct cooker mash Ground malt + water (35 C) protein rest (1 Hour) mash 67-68 C (starch hydrolysis start , keep for 20-30 minutes mashing off ( 75-80 Ctest for the absence of starch ( with iodine test) Excessive hydrolysis of proteins may result in a beer with little foam stability whereas too little hydrolysis might give rise to cloudy, unstable beer.

27. Mash tun

28. 3- Wort separation ( Lautering and Sparging ): a filtering process. mash husk and other insoluble materialsscreen clear liquid ( = wort)lauter tub Husk and other soluble solids: act like filtering medium. Recycle until to get clear liquid , which is called wort. sparging ( passing through water at 76 C ) is sarted.

29. 4- Boiling and hopping : ( copper, stainless steel) clear wort +hops brew kettle boiling , 1-1.5 hours , 5-8 % of water will be evaporated Purpose of brew kettle boiling; wort sterilization to concentrate wort by evaporating some of the water In activation of enzymes to fix the ratio of fermentable sugars to dextrin to control alcohol concentration. high molecular proteins forms large flocks and precipitate this is called as “ hot break” or “trub”.

30. Hops extraction and isomerization: water soluble resins, oils, tannins, amino acids andmonosaccharides are extracted from hops. 90 % of -acid humulone is converted to iso--acid humulone at pH=5.2 in1.5 hours. Of the total color developed, one third is developed during malting,two third is developed during boiling.

31. Color and flavor development: -oxidation of phenolic compounds, -maillard reactions between reducing sugars and amino acids -caramelisation of polyhydroxycarbonyl compounds. Wort is cooled to 48 C: additional protein ppt, called as “ cold break”. Wort is aerated: oxygen conc. to 8-10 ppm to support the initial growth of beer yeast.

32. 5- Fermentation : inoculate wort, “pitching” . wort ( at 9-10 C) exothermic rxn, 12-26 hours, temperature rise to 13 C foam forms ( called KREAUSEN ), vigorous CO2 production helps foam formation 4-5 days later CO2 production decreases kreausen collapse total 10-12 days of fermentation fermentables are completely utilized green beer after fermentation, yeast is removed by decantation, slurry centrifugation or combination of the two.

34. Plato

35. When the specific gravity no longer is decreasing: fermentation is complete.(4-7 days) The beer :”fully attenuated.” then quickly cooled to 4°C or less.

36. Flocculation the ability of yeast to agglomerate or adhere to one another in the form of clumps. lager yeasts: flocculate, the clumps have a density greater than that of the beer and settle to the bottom. Ale yeasts: form clumps or flocs that entrap CO2 bubbles and have a lower density, and, therefore, rise to the surface

37. If flocculation occurs prematurely, before the end of the fermentation, fermentable sugars will remain in the beer (refered as a “hanging fermentation”). (have a lower than normal ethanol concentration and are relatively sweet) yeast cells that fail to flocculate, and instead remain in the beer, are difficult to remove, causing cloudiness problems.

39. 6-Conditioning (Lagering, aging and finishing): • green beer • yeast from first fermentation • Ruh • ( lagering, ruh storing, aging ) • wooden casks ( now Stainless steel) ( from 20 L to more than 200 L. • It is secondary fermentation (Sugar is added to induce the secondary fermentation, and additional hops and finingagents may also be added. ) to assimilate small amount of residual maltotriose and to complete diacetyl assimilation, 2-6 weeks.

40. Processes performed are ; 1-Saturation with CO2 by -natural build up of CO2 during secondary fermentation or kreausening by applying counter pressure -sparging with CO2 in storage tanks -sparging with CO2 in line ( with CO2 collected during primary fermentation 2- Flavor maturation : Diacetyl, hydrogen sulfide, mercaptans and dimethyl sulfide produced during fermentation are decreased during secondary fermentation.

41. 3-Beer and foam stabilization : Three types of stability are required for beer; microbiological stability : -pasteurization ( 71°C to 75°C for 15-30 s, -5 logs), stable at room temp. for six months. • sterile filtration ( 0.45-85 m filters ) Beer can also be heat pasteurizedafter it has been filled into cans or bottles. most beer consumed in the USA is processed via tunnel pasteurization systems, heated by hot water. ( 62°C, 20 min).

42. physical stability : chill haze ( 0.1-0.2 m )forms at 0 C and redissolves at 20 C permanent haze ( 1-10 m ) remains even above 20 C. polypeptides, polyphenols: to prevent or delay haze formation ; a-) hydrolysis of polypeptides by papain b-) absorption of polypeptides by silica gel or bentonite c-) precipitation of polypeptides by tannic acid foam stability: Increase in viscosity, surface tension and elasticity will increase foam stability due to proteinaceous material, surface active hops components and gums)

43. Beer Components Carbon Dioxide packaged beers: 500–550 g CO2 hl−1. At 1 atm pressure and 0 °C: beer will dissolve no more than 200 g CO2 hl−1. If fobbing occurs spontaneously when a can or bottle is dispensed, it is called ‘gushing(excessive gassing or over-foaming when packaged beer is opened due to doxynivalenol from Fusarium.

44. Other Gases in Beer Oxygen:leading to cardboard and other stale notes and to the formation of haze. Brewers strive to minimize the oxygen level in beer yeast is powerful oxygen scavenger , only after the removal of yeast that oxygen is a concern). Nitrogen has long been introduced to beer to promote foam stability ……smaller bubbles. (more resistant to collapse

45. Additional beer defects • Wild yeasts Zygosaccharomyces, Kluyveromyces, and other Saccharomyces,do not flocculate creating cloudiness and filtration problems. • diastatic yeasts (like Saccharomyces cerevisiae var. diastaticus): can hydrolyze and ferment dextrins, • - they often produce phenolic off-flavors in the beer. - fermenting the body-forming dextrins, they make the beer “thinner. - aerobic yeasts produce acetic acid, volatile esters and alcohols, and other oxidized compounds, and cause turbidity problems.

46. synthesis of acrolein( imparts a bitter flavor). Pediococcus acidilactici, Pediococcus inopinatus, and Pediococcus damnosus : most objectionable defect in beer, namely, the production of diacetyl( imparts a buttery flavor) : “sarcina sickness. Stale beer: cardboard-like, rotten apple, cooked, or toffee-like flavors. caused by autooxidation rxns ( main factor that determines shelf-life of beer.) The best way to control staling is simply to keep oxygen out of the finished beer.

47. Lightstruck • “Skunky” aromaFormed from isomerized hop acids by exposure to ultraviolet light Very low treshold,ppt • Can be prevented • -by chemically reducing the hop acids • -by packaging the beer in cans or brown bottles

48. Light (Lite) Beer (….Dry beers) “light” means that there must be one-third fewer calories. By - dilute regular beer with water.adding 25% water , reduce calories, also reduce flavor, color, body, and the ethanol content. -adds enzymes: that hydrolyze a portion of the nonfermentable carbohydrates - GM yeasts that utilise dextrin

49. Non-alcoholic beer (<0.5% ethanol) first produced in the USA more than 80 years ago. methods : -removing the ethanol from normal beer by evaporation or distillation. -various filtration configurations, in particular, dialysis and reverse osmosis, are now more widely used. ( Beer quality is much better because they operate at low temperatures (-10°C))

50. - modifying the fermentation so that ethanol is not produced as an end product. -the fermentation at a low temperature (-5°C) that restricts yeast growth and ethanol formation. However, these methods may result in a beer that is too sweet and microbiologically unstable, due to high levels of residual sugars. - Modifying the wort composition by removing fermentable sugarsprior to fermentation to limit ethanol production.