Ultimate AC Tasting Exam- Off-Flavor Panel Flashcards
Tasting Beer: Sensory Vocabulary
Thiol: Dimethyl Sulfide (DMS)
Type: Aroma
Descriptors: Creamed corn, cabbage, vegetal at low levels; tomato juice in dark beers
Threshold: 30-50 ppb
Appropriate Styles: Usually not appropriate but at very low levels in some pale lager styles, German Pils, Munich Helles, Cream Ale (think Rolling Rock)
Source: Created in the boil from pre-cursor SMM, large amounts suggest infection
Tasting Beer: Sensory Vocabulary
Oxidation/ Trans-2-Nonenal (T2N)
Type: Aroma/ Flavor
Descriptors: oxidation, papery, stale, cardboard
Threshold: 0.05 to 0.25 ppb
Appropriate Styles: NONE
Source: Created in the brewing/ packaging processes due to exposure to oxygen, also magnified by aging or improper storage
Tasting Beer: Sensory Vocabulary
Phenol: Chlorophenol
Type: Aroma
Descriptors: antiseptic, mouthwash, plastic, Iodine, pool shed, vinyl, swimming pool
Threshold: Less than 0.5 ppb
Appropriate Styles: NONE
Source: cleaning chemical exposure during brewing/ packaging process, can also be from sanitizers at point of dispense
Tasting Beer: Sensory Vocabulary
Thiol: Hydrogen Sulfide (H2S)
Type: Aroma
Descriptors: Rotten eggs, Sewer gas
Threshold: Below 1 ppb
Appropriate Styles: Occasional “whiff” in German lager beers i.e. Helles
Source: Produced during fermentations but can also be a bacterial infection
Tasting Beer: Sensory Vocabulary
Acid: Isovaleric Acid
Type: Aroma
Descriptors: Stinky cheese, stinky feet
Threshold: 0.07 ppm
Appropriate Styles: NONE
Source: Improperly stored or aged hops or due to an infection
Tasting Beer: Sensory Vocabulary
Acid: Lactic Acid
Type: Aroma, Flavor
Descriptors: tart lemon/ yogurt, sour milk, sour cream, acidic sourness
Threshold:
Appropriate Styles: Gose, Berliner Weiss, Lambic, Fruit Lambic, Gueuze, Flanders Red Ale
Source: Formed by bacteria such as Lactobacillus or Pediococcus used in brewing to acidify a beer or via unwanted contamination
Tasting Beer: Sensory Vocabulary
Lightstruck | Thiol: 3-Methyl-2-Butene-1-Thiol (3MBT)
Type: Aroma
Descriptors: Skunky, rubbery, fresh brewed coffee
Threshold: .05 ppb
Appropriate Styles: NONE
Source: Interaction between blue light waves and hop bittering compounds, exposure to light
Tasting Beer: Sensory Vocabulary
Thiol: Mercaptan (Methanethiol, Ethanethiol)
Type: Aroma
Descriptors: Rotten, Garbage can, drainpipes
Threshold: 1.5 ppb
Appropriate Styles: Should not be detectable, but can add meaty complexity in some beers
Source: Produced by autolysis during fermentation, can also be a bacterial infection or from dry hopping
Tasting Beer: Sensory Vocabulary
Aldehyde: Acetaldehyde (AA)
Type: Aroma
Descriptors: Green apple, overripe apple, wet grass, raw pumpkin, latex paint, avocado: can be solventy as well
Threshold: Around 10 ppm
Appropriate Styles: Should not be detectable, can be common in Oud Bruin and Flanders Red Ales also common in American and American Light lager beers
Source: Produced during fermentation, common of “green” beer; caused by oxygen in packaging; wood aged beers
Tasting Beer: Sensory Vocabulary
Vicinal Diketone: Diacetyl/ 2-3-Butanedione
Type: Aroma/ Flavor
Descriptors: Buttery theater popcorn, in larger amounts butterscotch
Threshold: 10 to 40 ppb
Appropriate Styles: Sometimes at low levels in all Czech lagers, Oatmeal Stout, British Bitters, Dark Mild, and Tropical, Sweet and Foreign Extra Stouts
Source: Created in the fermentation process in large amounts bacterial contamination (dirty draft lines)
Tasting Beer: Sensory Vocabulary
Acid: Acetic acid
Type: Taste and Aroma
Descriptors: vinegar, sour
Threshold:
Appropriate Styles: Flanders Red Ale
Source: Oxidation of ethanol by Acetobacter bacteria, can also be caused by a zymomonas infection
Tasting Beer: Sensory Vocabulary
Metallic: Ferrous Sulfate
Type: Taste and aroma
Descriptors: Metallic, bloody, iron, coppery, bitter
Threshold: 0.15 ppm
Appropriate Styles: NONE
Source: Elements in the brewing water or exposure to metals in the process
