Sensory Analysis The Importance of Aromas and Flavors on Beer Lyn Kruger Siebel Institute of Technology Sensory Analysis The sensory analyst is considered an “instrument” Senses are used to: perceive and react to characteristics of food and beverages Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Sensory Analysis The sensory analyst is considered an “instrument”: Measure Analyze Interpret Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Sensory Analysis Humans as instruments cognitive and cultural bias individual acuity differences Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Sensory Analysis Sensory analysts may vary from one test to the next: Fatigue Adaptation Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Sensory Analysis Ability to discriminate between harmful and benign stimuli Health and age play a role Ability to improve with practice Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Sensory Evaluation: What we know Can taste many flavor compounds Basic tastes sweet, salty, sour, bitter, umami Acute sense of smell Trigeminal sensations: burning, cooling, tingling > 1,000 odors and flavors in beer Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Olfactory System Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Trigeminal Sensation Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Sensory Evaluation: Training objectives Establish memory for aromas and flavors recognize and identify aromas and flavors choose correct descriptors Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Flavor Wheel Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Basic Tastes: Sensory procedure Aroma impressions first, “drive by” then 2-3 short sniffs Small sips Allow sample to sit on tongue for a moment, then swallow Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Basic Tastes: Sensory procedure Avoid oversaturation and sensory fatigue Allow 15 - 60 seconds between samples to readapt receptors Less flavored samples before highly flavored samples Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Basic Tastes: What happens Beer sample quickly moderates towards 37°C in the mouth Immediate (in some individuals copious) secretion of saliva in response to oral stimulation This is promoted in beer by its acidity, alcohol content and high level of carbonation. Saliva is a well-buffered, high pH (7.0) diluent, and influences the sensory perception of beer Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Sensory Analysis BREWHOUSE ASSOCIATED FLAVORS Lyn Kruger Siebel Institute of Technology Flavors Associated with Brewhouse Positive Flavors Malty Hoppy Bitter Off flavors Dimethyl sulfide (DMS) Isovaleric acid Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Malty: Typical Flavors Standard Malts Cereal Grain Sweet Nutty Malty Roasted Malts Burnt Bitter Coffee Caramel/Color Malts Caramel Toffee Nutty Slightly burnt Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Hoppy & Bitter Hoppy Use Aroma hop varieties Aroma Associated with Hop Oils : Floral Compounds Citrus Compounds “Noble aroma” -herbal, spicy - oxidation products Bitter Use Bittering hop varieties Bitter flavor associated with resins Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Dimethyl Sulfide (DMS) Flavor creamed corn, vegetable, oysters, tomato juice Formation Precursor (S-methyl methionine [SMM]) formed in the barley Some SMM remains in the malt During wort boiling SMM is converted to DMS and lost by volatilization Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Isovaleric Acid Flavor cheesy, sweat socks Production Formed in old hops Organic acid Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Sensory Analysis FERMENTATION RELATED FLAVORS Lyn Kruger Siebel Institute of Technology Esters Flavors fruity, banana, apples, perfumy, solvent, nail varnish remover Production Reaction of alcohol group and acid group in the yeast cell Iso amyl acetate Ethyl Acetate (Fruity) (Solvent) Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Diacetyl Flavor buttery, butterscotch Production During yeast growth in fermentation When the yeast has to make a specific amino acid - valine Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Sulfur Compounds Flavor sulfury, rotten eggs, burnt rubber, striking a match Production Intermediates in amino acid metabolism When yeast needs to make sulfur containing amino acids Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Sensory Analysis STORAGE ASSOCIATED FLAVORS Lyn Kruger Siebel Institute of Technology Flavors associated with Product Storage Any flavor changes after maturation - generally negative (off-flavors) Few exceptions (e.g. barley wines) Flavors normally associated with staling of the beer Papery Bready/Cooked Skunky Aldehydic Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Papery Flavor papery, wet cardboard, stale. Formation Oxidation of linoleic acid Forms trans-2-nonenal (an aldehyde) Very low flavor threshold (1 ppb) Oxygen /light promotes reaction Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Bready / Cooked Flavor cooked breakfast cereal, oxidized, cooked Formation Overpasteurization( particularly in the presence of air) Oxidation reactions Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Aldehydic Flavor Nutty, toffee, honey, green apples, aldehydic Formation Degradation Oxidation of Oxidation of Oxidation of Oxidation of of amino acids higher alcohols isohumulones lipids ethanol (acetaldehyde) Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Sensory Analysis CONTAMINATION RELATED FLAVORS Lyn Kruger Siebel Institute of Technology Flavors associated with Contamination These flavors are generally off-flavors Can be microbial or non-microbial Microbial Variety - depending on microorganism Cloves (eugenol, 4-vinylguaicol) Acidic (lactic, acetic acid) Diacetyl DMS Sulfur Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Microbial: Cloves / Spicy Flavor phenolic, cloves, spicy Formation Associated primarily with wild yeast In some beer styles - deliberate Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Acidic Flavor sour, vinegar, sour milk, acetic, lactic acid, acidic Formation Beer spoilage bacteria Lactic acid bacteria - Lactobacillus & Pediococcus Produce lactic acid and acetic acid (only Lactobacillus) Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Diacetyl Flavor buttery, butterscotch Formation Beer spoilage bacteria Lactobacillus & Pediococcus Wort spoiling bacteria Enterobacteriacea Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology DMS Flavor cooked vegetable, corn, olives, oysters Formation Wort spoiling bacteria Often grow in plate heat exchangers Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology Sulfury Flavor sulfur, rotten eggs, mercaptan Formation Wort spoiling bacteria Beer spoilage bacteria Sensory Analysis: The Importance of Aromas and Flavors on Beer Lyn Kruger, Siebel Institute of Technology