Introduction to Alcoholic Beverages

2. Introduction to Alcoholic Beverages Robert S. Wallace Department of Ecology, Evolution, and Organismal Biology Iowa State University Ames, Iowa 50011

3. Introduction to Alcoholic Beverages:Beer

4. What is Beer? • A fermented (alcoholic) beverage derived from grains. • Flavorings are often added to balance residual sweetness of unfermented sugars and other polysaccharides; bitter flavors used most. • The fermentation organism is typically a yeast species within the genus Saccharomyces. • Most beers have natural or intentionally added carbonation.

5. Origins of Beer • Earliest evidence for the deliberate production of beer dates to at least 5,500 BCE in Sumeria. • Use of domesticated barley is evident from impressions of grains in vessels • Original beers were likely spontaneously fermented, and may have been derived by soaking roasted barley cakes in water. • Beers that had finished fermenting likely had sediment and floating debris; the clear liquid in the middle was drunk through reeds – precursors of our modern ‘straws’.

6. A Sumerian bas-relief sculpture depicting the drinking beer from amphora-like vessels.

9. Selection for attributes of “full” heads that do not shatter, and multiple fruits drove the domestication process • Different qualities selected for various uses of the grain: e.g. baking versus brewing. 6-row 2-row

12. Palea and lemma remain in cleaned grains. • These form the ‘husk’ that is desirable in barley • to form the filter bed during mashing and sparging.

16. Malting • Malting is the process of germinating viable seed to allow the embryo to develop enzymes (amylases, and others) which are capable of breaking-down stored carbohydrates, typically in the form of starch, and then stopping this growth at a specific stage of development through kilning. • The process begins by imbibing the seed with water to initiate germination. • Germination under aerobic conditions continues until a critical stage of development, when the process is rapidly stopped by heating and drying the germinated seed. • Traditional malting techniques included carrying out this process on the floors of special facilities, and processing the germinating grains by hand. • Modern techniques involve bulk processing of grains in specialized malthouses, most involving the use of automated troughs or (Saladin) boxes in environmentally controlled conditions.

17. Floor Malting - DeWolf-Cosyns Malting, Brussels, Belgium

19. Adolph Coors Brewing Company, Golden, Colorado

20. Cargill Malting, Stevens Junction, Wisconsin

21. Malting: Filling the Saladin Box • Following imbibition of the grain in the steeping tanks, the grain is sent through pipes in a grain-water slurry. • The grains fill a long trough which is kept under cool temperatures and high humidity which favors germination condition. • A series of automated augers turn the grainbed during the germination process to assure uniformity and maintain aerobic conditions for the sprouting grains.

22. Saladin Box - Cargill Malting, Stevens Junction, Wisconsin

24. Adolph Coors Brewing Company, Golden, Colorado

26. Kilning of Malt - I • Once the critical stage of germination and embryo growth has been achieved, the process needs to be abruptly stopped. • The germinated grain is transferred to a kilning box where hot, dry air is passed through the grain bed, which kills the embryo (without effecting the enzyme characteristics), and dries the malt to an acceptable moisture content. • The malt is then cleaned of rootlets and other structures, and prepared for packaging and shipment. • Extensive biochemical and physical assays determine the malts brewing (or other) characteristics. • Specialized kilning of certain malt products under a range of temperature and moisture conditions, for varying lengths of time, produce ‘specialty’ malts that are widely used in brewing.

27. Cargill Malting, Stevens Junction, Wisconsin

28. Kilning of Malt - II • Kilning done with wet malt under closed conditions results in “crystal” or “caramel” malt due to thermal saccharification of starches. • “Roasting” or dry kilning of malt results in ‘darkening’ or ‘browning’ of the grains due to Maillard reactions: α-amino acids + [O2] (Maillard products) sugars (colorless or pale) melanoidins heat (dark color)

29. Malt color is determined by kilning – Measured in degrees Lovibond

30. Melanoidins contribute to beer color…..

31. Other Grains Used in Brewing • A variety of grains other than barley are used in the brewing process as adjunct grains. These typically do not have the same enzymatic composition as barley, but do provide alternative sources of fermentable carbohydrates, along with a range of aromatic and other flavor compounds. • Main Adjunct Grains: Wheat – Triticum aestivum Rice – Oryza sativa Oats – Avena sativa Rye – Secale cerale Corn – Zea mays Sorghum – Sorghum bicolor Millet – Panicum milleaceum

35. Starch Conversion - Mashing • Necessary to activate enzymes produced by grass embryos by re-hydrating crushed grains. • Temperature raised to optimum temperature to enable enzymatic breakdown of starch into component sugars. • Selection of temperature and duration of mash will determine fermentability of the resulting wort. • Mashing also liberates medium molecular weight proteins which contribute to mouthfeel and heading characteristics.

36. Teak Mash Tuns – Shepherd-Neame Brewery, Faversham, Kent, England

37. Teak Mash Tun – Shepherd-Neame Brewery, Faversham, Kent, England

38. Mash Tun No. 1 – Fuller, Smith & Turner Brewery, Chiswick, London, England

39. Carbohydrate Components of Malt • Poly 1,4 glucose, amylose (starch) - straight chains - simple, easily-digested by amylases • Beta-glucans - have both 1,4 and 1,3 bonds - partially digestible with amylases • Amylopectins - branched starch molecules - branching with 1,6 bonds typical - partially fermentable

40. Mashing – Amylase Activity Alpha Amylase (to = 158º F; 70º C) …G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G …G-G G-G-G-G-G-G G-G G-G-G-G G-G-G-G G-G-G-G-G G-G Beta Amylase (to = 140º F; 60º C) …G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G …G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G-G G-G …G-G-G-G-G-G-G-G-G-G-G-G-G-G-G G-G G-G G-G G-G G-G

41. Sweet Wort and Boiling • Following mashing of the grain, the solubilized sugars and oligosaccharides in solution are run off the grain bed to a boiling vessel (the “kettle”). • The “spent” grain bed is washed with hot (170º F 77º C) water in a process known as spargingto dissolve residual sugars. • At this point, the sugar solution is termed ‘sweet wort’ which is then boiled for an hour or more. • During the boiling process, hops are added and a variety of chemical processes occur which result in the liquid becoming bitter; thus it is now termed ‘bitter wort’.

42. Hops – Humulus lupulus(Family Cannabaceae) • Hops are dioecious vining perennials, having extensive stem structures: • Aboveground stems (bines) and leaves dying at the end of the growing season in most areas. • Belowground stems (rhizomes) and roots overwintering. Rhizomes serve as primary means for vegetative (clonal) propagation of female plants for commercial production. • Desired product is the dried inflorescences (“strobiles” or “cones”) of the female plant which have lupulin glands on the bracts and bracteoles which subtend the minute flowers. • Male hop plants are used primarily for breeding purposes’ in some cases male hops are planted to assist in improving yield (e.g. British varieties). • Female inflorescences (“burs”) continue development even if flowers are not pollinated (wind).

43. Cannabaceae: The Hemp/Hop Family • Related to the Elm (Ulmaceae), Mulberry (Moraceae) and Stinging Nettle (Urticaceae) families. • Wind-pollinated. • Family with 2 genera: • Cannabis – 1 (2) species. • C. sativa [hemp; marijuana] • Humulus – 2 (3) species • H. japonicus – Japanese hop • H. lupulus – brewing hop

44. Cannabis sativa L. Hemp cultivar (male)

45. Humulus lupulus Brewing hop – (female)

46. Yakima Valley, Washington

47. Yakima Valley, Washington

48. Female inflorescences of Hops (“Cones”) • Desired product is the dried dried inflorescences (“strobiles” or “cones”) of the female plant which have lupulin glands on the bracts and bracteoles which subtend the minute flowers. • Male hop plants are used primarily for breeding purposes’ in some cases male hops are planted to assist in improving yield (e.g. British varieties). • Female inflorescences (“burs”) continue development even if flowers are not pollinated (wind).

49. Female hop Inflorescences: “Bur stage” • Female inflorescences have all pistillate flowers with stigmas extending beyond bracts and bracteoles. This is considered the “bur stage” • Stigmas are receptive to windborne pollen at this stage. • Female inflorescences (“burs”) continue development even if flowers are not pollinated (wind).

50. Mature Female Hop inflorescence • Composed of bracts and bracteoles that completely cover the minute pistillate flowers. • Compound inflorescences (groups of individual cones) arise from axillary branches. • Hops are ready to harvest when the bracts and bracteoles become papery and somewhat dry. Lupulin production will have achieved its maximum at this stage.