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Beverage-ind.pptx
- 1. Outline History Ingreedients Barley, Hops, Yeast, Water Brewing process The processing, and what effects we expect them to have on properties of the final product Beer characteristics The properties that we observe, and how they were derived from the processing of the ingredients Conclusion & links for more info
- 2. RAW MATERIALS The main raw materials for beer production are: Cereals Malt ,mainly barley Water Hops and Yeast
- 3. Finishing 0peration Finishing 0peration Fermentation house (Beer processing) Brew house Malt plant or Malt house
- 4. Grain Barley Higher extract, less husk Preferred by both home and Industrial breweries Other Grains Wheat, Oats, Corn, Rice
- 7. Malting Grain (usually barley) is malted Harvested grain is soaked in water until it germinates This activates amylases (and proteases) Grain is dried This halts the conversion Acrospires (sprouts) are removed Grain is cured usually at least one month
- 8. Barley Malting Acrospires eat endosperm as they grow during malting Acrospire is the sprout, endosperm is its food source (full of starch) Acrospires will continue to eat endosperm until it is depleted or they are stopped by the maltster by heating and drying Longer acrospire growth leads to: More endosperm consumed and less fermentable sugar More amylases are activated More yeast nutrients released Clearer beer and more complete fermentation
- 9. Water:The medium for fermentation 3 main concerns Flavor of water Nutrients for yeast Can’t use distilled water pH effects how well enzymes make maltose Keep mash pH 5-5.5 Ion concentration important e.g. Ca2+, Mg2+, CO3 2- Darker malts lower pH more than lighter malts Areas with water with natural higher pH produced darker beers than areas with water with lower pH
- 10. Hops Humulus lupulus (family = Cannabinaceae) Perennial Bitter herb grown on a vine and composed of leaflike bracts and bracteoles Bracteoles have lupulin glands that produce resins containing alpha acids Alpha acids – provide bitter taste/flavor and preservative Oils from the plant add flavor and aroma
- 11. According to studies the average composition of hop dry weight is approximately Bitter substances or hop resins 18.5 % Hop oil 1.0 % Polyphenols 3.5 % Protein 20.0 % Inorganic 8.0 % cellulose and other materials 49.0%
- 12. Yeast fermentation catalyst The most important and mysterious ingredient turns wort into beer and produced more of itself Through anaerobic respiration, it converts the malt sugar into alcohol, CO2, and other by-products Often removed after fermentation, and can be re-used Yeast is essentially a fermentation catalyst The word “enzyme” (meaning biological catalyst)
- 13. Yeast 2 main types (for brewing purposes) Saccharomyces cerevisiae (ale yeast) Prefers warmer temperatures (20-25°C) and will flocculate on top of the beer Saccharomyces uvarum (lager yeast) Prefers cooler temperatures and will flocculate at the bottom of the beer (~5°C)
- 14. MALTING: The first ingredient to come into play is barley, which is grain (or, in other words, a seed). The seeds are soaked in water for about two days and allowed to begin their development into plants. Enzymes are released that break down the proteins and starches in each grain into simple sugars meant to nourish the baby plant. However, once this process has begun, the barley is cooked in a kiln, arresting the growth process while the enzymes are at their peak of production. This is called malting.
- 15. Malt Germinated and crushed grain Amylases (and proteases) accessible but inactive Starches from endosperm partially broken down
- 16. Column1 Moisture content (wt/%) Volume (hl) Mass (kg) Malting barley 14 100 100 Steeped barley 41 145 145 Green malt 48 220 147 Stored malt 3.5 118 79 4.7 120 80
- 17. Alpha Acids Humulone R = CH2CH(CH3)2 Cohumulone R = CH(CH3)2 Adhumulone R = CH(CH3)CH2CH3
- 18. MASHING: In the mashing stage, the grain is actually transformed into sugar. The grains are crushed into a fine powder, or grist, and then soaked in water. Proteins are broken down. Starches are broken down into simple sugars that nourish the yeast. Complex sugars remain to give the beer its malty taste. The mash is heated and strained to yield a substance called wort. Next, the wort is brought to a boil and the flowers of the female hop plant are added. Bitter resins and aromatic hop oils are released. The variety of hop, the amount added, and the point or points in the boil at which they are added all contribute to the flavor of the beer. They add bitterness when added early to the boil, flavor if added in the middle, and aroma when added at the end.
- 19. Mashing & Lautering Mashing Malt is soaked in hot water ~155°F (~68°C) Amylases re-activated starches broken down to sugars Primarily maltose = 2 glucose joined by α(14) linkage Proteins also broken down Processing of proteins and starches highly dependent on temperature pH also important for amylase activity Lautering Grains are rinsed until water comes through clear Extract all ingredients into wort to be boiled
- 21. FERMENTATION: The wort is then cooled and moved into a fermentation vessel. Yeast is added and allowed to consume most or all of the sugars in the wort. This is the fermentation process during which alcohol is produced. The process takes about ten days. Each brewery has its own strains of yeast, and it is the yeast that determines the character of the beer.
- 22. Pitching Yeast Addition of yeast to allow fermentation Wort must be at proper temperature for yeast to survive and flourish Slightly off temperatures lead to off flavors Far off temperatures lead to stuck fermentation Oxygen must be kept out Yeast only converts sugars to alcohol and CO2 under anaerobic respiration With oxygen present, aerobic respiration will dominate
- 24. Fermentation Yeast absorbs oxygen and sugar, and reproduces asexually When oxygen is used up, reproduction stops and fermentation (anaerobic respiration) begins Each glucose produces two molecules of ethyl alcohol and CO2 C6H12O6 2 CH3CH2OH + 2 CO2 + 118 kJ (2 ATP) Large amounts of CO2 are produced and must be removed without letting oxygen in Airlock or water bubbler
- 25. Fermentation When all fermentable sugars have been consumed, fermentation stops and yeast begins to go dormant Yeast settle out and the beer clarifies This yields a “young beer” Bad taste and smell High concentrations of diacetyl and other organic byproducts
- 26. STORAGE: The beer is then separated from the yeast (racked). Once the yeast is removed the beer is passed from fermentation to storage vessels. During transfer the beer is cooled to minus one degree centigrade. The beer stays in storage at this temperature, and any material which might impair the appearance, flavour and shelf-life of the beer settles out. FILTRATION: Following a set time in storage, carbon dioxide gas collected during fermentation is added to give beer its characteristic head and sparkling taste. The beer is then passed through a filtration system to remove surplus yeast and protein.
- 27. Conditioning Small amounts of remaining yeast continue to consume byproducts of initial fermentation Conditioning or aging, development of flavor
- 28. PASTEURISATION: This is a process of heating and rapid cooling which prolongs shelf-life and destroys any bacteria or other organisms in the beer. Canned and bottled beers are pasteurised in their containers, while draught beer is pasteurised by means of a special heat exchanger called a flash pasteuriser. PACKAGING: The filtered and sparkling beer is packaged into bottles, cans and stainless steel casks, or kegs, ready for distribution.
- 29. Packaging Flat beer is packaged (bottle or keg) and must be carbonated Add extra sugar for natural carbonation by fermentation Artificially carbonate from gas source
- 30. Beer Characteristics Alcohol Content Flavor Malt, Hops, Yeast, Water Aroma Clarity Head Preservation
- 31. Alcohol Content Measured by density Original gravity – density of wort prior to fermentation Final gravity – density of beer after fermentation Dissolved sugars lead to high density As sugars convert to ethyl alcohol, the density decreases The decrease in the density is directly proportional to the amount of alcohol present
- 32. Flavor Sweet flavors from malt Dependent on types of grain and on grain modification Bitter flavors from hops Isoalpha acids balance sweetness of grain 15 – 100 ppm depending on beer type Aroma from hop oils mainly from later additions of hops
- 33. Aroma Hop oils Small organic molecules Often aromatics Polyphenols Mainly from late addition of hops Aroma hops boiled for a short time (~5 minutes) Dry hops (added after wort has cooled or just before packaging) Phenol
- 34. Clarity Filtering, siphoning, settling, racking Yeast Flocculency of yeast Polyphenols from hops Larger polyphenols become insoluble and form a “permanent haze” Small polyphenols agglomerate when chilled to form a “chill haze”
- 35. Head Protein from grains Wheat proteins stabilize head Isoalpha acids Tensioactive properties of isoalpha acids stabilize head
- 36. Preservation Alcohol is a natural preservative Alpha acids Act as a preservative by inhibiting the growth of bacteria Beta acids (also from hops) also help Decomposition on exposure to light Isoalpha acids are light sensitive Skunky flavor Only a few ppb http://www.scielo.br/scielo.php?pid=S0100- 40422000000100019&script=sci_arttext
- 37. More Info Stephen Snyder, The Brewmaster’s Bible, New York: HarperPerennial, 1997 http://www.scientiaevitae.de/gb/2/5/beer.htm Hop Chemistry: http://www.scielo.br/scielo.php?pid=S0100- 40422000000100019&script=sci_arttext
- 38. Drink! COLD GOLD
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