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The Biology of Lager Yeast

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1 The Biology of Lager Yeast
The Art of Brewing and The Biology of Lager Yeast Tom Pugh Miller Brewing Company

2 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Purpose Provide a better understanding of... The brewing process Types of brewing yeasts Attributes important to the brewer Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

3 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
The Art of Brewing Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

4 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Definition of Beer An alcoholic beverage produced by the fermentation of sugar-rich extracts derived from cereal grains or other starchy materials. Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

5 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
History of Brewing Man has been making beer since the dawn of civilization. Where grain was grown, beer was made. Sumaria (4000 BC) Sikaru Egypt (3000 BC) Zythum India (2000 BC) Sura China (2000 BC) Kiu Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

6 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
History of Brewing Sumarian beer recipe 3000 BC Resembled liquid bread: Barley and Emmer Spices / fruits No Hops Safe, nutritious, and exhilarating beverage. Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

7 The Role of Yeast in Brewing
Unwittingly, ancient brewers domesticated yeast. Selected yeast that made good beer. Deduced that yeast was important to make beer. Collect the creamy foam or sediment from one brew. Use it to pitch the next brew. Did not know what yeast was. Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

8 The Role of Yeast in Brewing
1680 Antonie van Leeuwenhoek Observed yeast in beer. Cagniard Latour Microbe is responsible for alcoholic fermentation. 1839 -Justus von Liebig and Friedrich Wohler Alcohol is produced by a chemical process in which dead and decaying yeast participated. Satired Latour’s theory in Annalen der Chemie . . . Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

9 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
….small animal which sips sugar through its snout, and excretes alcohol from its gut and carbonic acid from its urinary organ. Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

10 The Role of Yeast in Brewing
Louis Pasteur Yeast was responsible for alcoholic fermentation. Emil Christian Hansen Developed pure culture technique Isolated pure cultures of brewing yeasts Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

11 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Brewing Yeasts Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

12 Types of Brewing Yeasts
Two types of brewing yeasts, originally classified on flocculation behavior… Top-fermenting Ale yeast Weiss yeast Bottom-fermenting Lager yeast Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

13 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Weiss Ale Lager Lab Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

14 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Ale Yeast Predominant brewing yeast prior to the mid-1800s. Displaced by lager yeast Strains are genetically more diverse - several origins Warm fermentation temperatures: 65 to 72 °F. Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

15 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Weiss Yeast Bavarian origins - closely related. Produces beer that has spicy, clove, vanilla, and nutmeg flavor notes - POF. PAD1 gene phenylacrylic acid decarboxylase Decarboxylation of ferulic acid forms 4-vinyl-guaiacol, which gives the characteristic clove flavor. Warm fermentation temperatures: 65 to 72 °F. Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

16 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Lager Yeast Bavarian origin. 1400s in Munich - cool fermentations (selective pressure) Taken to Pilsen and Copenhagen in 1840s Pale malt, soft water, aromatic hops Became very popular - displaced ale yeast Popularity fueled by advances of Industrial Revolution Steam power, refrigeration, railroads, pasteurization and filtration technology Strains are closely related - common origins Cool fermentation temperatures: 42 to 52 °F Beers are more delicate, clean, drinkable, and less aromatic. Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

17 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Taxonomy Ale and Weiss yeasts - Saccharomyces cerevisiae Polyploid and probably aneuploid. Non-mating Sporulates poorly and poor spore viability Lager yeast - Saccharomyces pastorianus S. cerevisiae S. carlsbergensis S. uvarum Sporulates very poorly - poor spore viability Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

18 Distinguishing Characteristics
Colony morphology Microscopic appearance Chain formation Fermentation characteristics Flocculation behavior / flavor compound profiles Growth at 37 °C Melibiase Electrophoretic karyotyping Yeast 37 °C Melibiase POF Lager Ale Weiss Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

19 Distinguishing Characteristics
Difficult to distinguish between different lager yeasts using conventional techniques Colony and cell morphologies similar Fermentation characteristics PCR - limited success Electrophoretic karyotyping Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

20 Genome Structure - Lager Yeast
Allopolyploid and probably aneuploid. Tetraploid Natural hybrid S. cerevisiae and S. bayanus S. cerevisiae and S. monacensis Contains two types of chromosomes S. cerevisiae type S. bayanus type Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

21 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Genome Structure Gene order and function highly conserved Single chromosome transfer experiments Gene length similar, but nucleotide divergence. Low levels of recombination between homeologues Gene Nt. Identity AA. Identity ILV1 86 % 96 % ILV MET URA Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

22 Electrophoretic Karyotypes
cerev. parad. Lager Ale Lab Weiss Lab Lager bayan. Ale pastor. XII XII IV IV XV, VII XV, VII XVI, XIII XVI, XIII II, XIV X II, XIV XI X XI V VIII V, VIII IX IX III III VI VI I I T C C Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

23 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
The Brewing Process Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

24 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Ingredients Malted barley Cereal Adjunct Hops Water Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

25 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Malted Barley Two types of barley 2-rowed 6-rowed Provides fermentable sugars, flavor, and color. Malting process: Steeping Germination Kilning Purpose: Activate enzyme systems Preserve for brewhouse Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

26 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Steeping Soak, aerate, drain. 2 days Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

27 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Germination Ventilated to remove CO2 Repeated turning 4 to 5 days Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

28 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Cereal Adjuncts Types of adjuncts commonly used: Corn grits Rice Corn syrups (high maltose and dextrose) Purpose: Additional source of fermentable sugars Lighter body Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

29 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Hops Spice of beer Provides aroma and bitterness Flower (cone) of a vine-growing plant Humulus lupulus Female triploid Used as: Whole cones Pellets Extracts Lupulin Glands Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

30 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Hops Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

31 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
The Brewing Process Step Purpose Brewhouse Starch Sugars Wort production Fermentation Sugars Ethanol Flavor production Carbonation Flavor maturation Lagering Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

32 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
The Brewing Process Malt Mill Cereal Cooker Mash Tun Brink Fermentation Lauter Tun Brew Kettle Hops Aeration Lagering Hot Wort Receiver Wort Cooler Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

33 Mash Tun / Cereal Cooker
Activate malt enzymes Convert starch to fermentable sugars Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

34 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Lauter Tun Strainer Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

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Brew Kettle Sterilization Protein coagulation Hop extraction Volatile removal Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

36 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
The Brewing Process Malt Mill Cereal Cooker Mash Tun Brink Fermentation Lauter Tun Brew Kettle Hops Aeration Lagering Hot Wort Receiver Wort Cooler Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

37 Wort Composition Carbohydrates
73% Fermentable Fermentable Non-fermentable Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

38 Wort Composition Fermentable Sugars ** need to adjust to normal wort
Maltose Glucose Maltotriose Fructose Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

39 Wort Composition Amino Acids (** adjust to normal wort)
Ala Arg Asp Glu Gly His Ile Leu Lys Met Phe Pro Thr Tyr Val Asn Gln Ser Not included: Cys (2 ppm) and Trp (50 ppm) Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

40 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
The Brewing Process Malt Mill Cereal Cooker Mash Tun Brink Fermentation Lauter Tun Brew Kettle Hops Aeration Lagering Hot Wort Receiver Wort Cooler Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

41 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Fermentation Yeast growth Alcohol and CO2 Flavor compounds Large - 600,000 L Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

42 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Lagering Carbonation Off-flavor reduction Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

43 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
The Brewing Process Malt Mill Cereal Cooker Mash Tun Brink Fermentation Lauter Tun Brew Kettle Hops Aeration Hot Wort Receiver Lagering Wort Cooler Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

44 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Balanced Growth Yeast growth affects beer flavor. Need balance between yeast growth and beer flavor. The brewer needs... Desired flavor profile in desired time. Sufficient yeast crop for subsequent fermentations. Oxygen is growth limiting nutrient. Control point Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

45 Yeast Metabolism During Fermentation
Sugars Oxygen Membranes Glucose CO2 Energy Unsaturated Fatty Acids Sterols Esters Pyruvate Ethanol Higher Alcohols TCA Cycle Amino Acids Acetaldehyde VDK Organic Acids Sulfur Volatiles Amino Acids Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

46 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Higher Alcohols Formed by the decarboxylation and reduction of a-keto acids. From amino acid anabolism and catabolism. Alcohol Amino Acid a-keto acid Isoamyl Leucine a-keto-isocaproate Amyl Isoleucine a-keto-3-methylvalerate Isobutanol Valine a-keto-isovalerate Propanol Threonine a-keto-butyrate Alcoholic, solventy, and fruity flavor notes Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

47 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Esters Closely linked to lipid metabolism - growth. Reaction of an alcohol and fatty acid intermediate Acetate esters Ethyl acetate solventy, fruity, sweet Isoamyl acetate banana Phenethyl acetate roses, honey, apple Fatty acid esters Ethyl caproate apple, aniseed Ethyl caprylate apple Isoamyl decanoate tropical fruits Fruity flavor notes Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

48 Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company
Vicinal Diketones Pentanedione Threonine a-ketobutyrate a-acetohydroxybutyrate Isoleucine pyruvate a-acetolactate Valine Diacetyl Buttery, butterscotch flavor Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

49 Thanks to David Ryder of Miller Brewing Company and Tom Pugh, formerly of Miller Brewing Company, for providing this presentation to the Saccharomyces Genome Database for dissemination to the yeast community.


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