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122 Cards in this Set
- Front
- Back
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Diacetyl - flavour |
Butter, butter popcorn |
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Diacetyl - Chemical |
2,3-butanedione |
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Diacetyl - origins |
Produced from a precursor (alpha-acetolactate) from brewers yeast in fermentation. Also may be contamination from lactic acid bacteria （such as lactobacillus or pediococcus) |
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Diacetyl - confusions |
Butyric acid Vanillin Isobutyraldehyde |
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Diacetyl - comments |
Desirable flavour in some beers (Czech pilsner for example). Other lagers it is an off flavour. Considerable effort is made by most breweries to keep it below threshold |
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H2S - flavour |
Boiled/rotten eggs |
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H2S - Origins |
Produced by ale and lager yeast during fermentation and maturation The amount produced (and most importantly retained) varies on wort composition, yeast strain and fermentation conditions |
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H2S - confusions |
Sulphur dioxide Ethanethiol Methanethiol |
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H2S comments |
Present in all beers, concentration varies considerably from beer to beer, common in burton ales. At low levels can give a perception of freshness |
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Indole - flavour |
Like pigs on a farm |
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Indole - Origins |
Formed by contaminant ‘coliform’ bacteria during fermentation Often produced simultaneously with DMS (contaminant) |
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Indole - confusions |
Octanoic Acid Benzaldehyde Damascenone |
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Indole - comments |
Off flavour in lagers always and stouts, can smell to some artisanally pleasant (jasmine, floral) or to others seriously bad (faecal, dirty) - it’s about 50/50 for the population |
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Isoamyl Acetate - Flavour |
Bananas or pear drops |
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Isoamyl Acetate - Origins |
Produced by both ale and lager yeast. Amount depends on wort, yeast strain and fermentation conditions Signature flavour for some German style wheat beers |
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Isoamyl Acetate - Origins |
Produced by both ale and lager yeast. Amount depends on wort, yeast strain and fermentation conditions Signature flavour for some German style wheat beers |
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Isoamyl Acetate - Confusions |
Ethyl Hexanoate Ethyl Acetate Ethyl Butyrate |
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Isoamyl Acetate - comments |
Present in all beers Key flavour for some beers and signature flavour for German wheat beer Can disappear during aging, contributes to lack of freshness |
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Isovaleric Acid - Flavour |
Stale cheese or sweaty socks |
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Isovaleric Acid - origins |
Breakdown of alpha acids from hops. High hopping rates, degraded hops (&hop extracts) Occasionally produced by wild yeast, Brett being a specific culprit |
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Isovaleric Acid - confusions |
Butyric Acid Ethyl Butyrate 2,3-Butanedione |
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Isovaleric Acid - comments |
Often associated with beers of very high bitterness, definitely an off flavour in pale lagers Intensity increases as pH value decreases |
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Acetaldehyde - flavour |
Green apple or emulsion paint |
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Acetaldehyde - Origins |
Acetaldehdye is produced from wort sugars and then reduced into ethanol so it usually suggests fermentation problems Can also result from poor control of TPO |
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Acetaldehyde - confusions |
Ethyl Hexanoate 2,4,6 Trichloroanisole |
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Acetaldehyde - comments |
Present in all beers, common in Biere de garde, off flavour in high concentrations Intensity is influenced by sulphur dioxide concentration in the beer |
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Trans-2-nonenal - Flavour |
Papery, cardboard or oxidised beer |
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Trans-2-nonenal - Origins |
Nonenal is formed during malt and wort production, binds to malt proteins and is carried through the brewing process. Released during storage |
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Trans-2-nonenal - confusions |
2,4,6 Trichloroanisole Isobutyraldehyde |
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Trans-2-nonenal - comments |
Sulphur dioxide reduces the flavour impact of trans 2 The less effort you put in to minimising process oxidation the more trans-2 problems you will have from aging beer |
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Lightstruck - Flavour |
Skunk, freshly brewed coffee Marijuana (unofficial) |
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Lightstruck - Chemical |
3-methyl-2-butene-1-thiol |
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Lightstruck - Origins |
Formed when beer is exposed to light Daylight or artificial light Reaction involves hop bitter acids, vitamins and sulphur compounds |
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Lightstruck - Comments |
Consumers are fairly tolerant of this off flavour Jever pils, corona examples of beers which are skunked |
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Catty - flavour |
Catty like black currant juice or tom cat urine |
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Catty - Chemical |
P-methane-8-thiol-3-one |
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Catty - origins |
Can be Contamination of malt with mesityl oxide Can be formed during during ageing Can be from certain hop varieties (and may be a positive when occurring this way) |
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Catty - confusions |
Ethyl butyrate Ethanethiol Methanethiol Damascenone |
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Catty - comments |
P-methane-8-thiol-3-one is not the only compound to impart catty flavours in beer it is the one used in the aroxa flavour standard |
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Damascenone - flavour |
Berries Stale highly hopped beer |
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Damascenone - Origins |
Formed from breakdown of precursors derived from hops Increases during ageing
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Damascenone - comments |
Recorded by Aroxa as being a difficult flavour for tasters to describe and descriptors can be inconsistent Amount is proportional to amount of green hop material added to the wort According to internet it’s a primary odorants of Kentucky bourbon and is also often described as rose, taste seems to sometimes be described at woody and tobacco |
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4-ethyl phenol - flavour |
Band aid, barn, mice Brett infection |
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4-ethyl phenol - origins |
Continent yeasts like Brett (Dekkera) and occasionally by lactic acid bacteria |
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4-ethyl phenol - comments |
Saccharomyces does not produce 4-EP Characteristic in styles with Brett |
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4-vinyl-guaiacol - flavour |
Clove |
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4-vinyl guaiacol - Origins |
Produced during wort production then formed during fermentation Produced by yeasts with the PAD gene The enzyme associated with the PAD gene produced 4VG from malt derived ferulic acid |
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4-vinyl guaiacol - confusions |
Vanillin Sulphur dioxide Isobutyraldehyde |
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4-vinyl guaiacol - Comments |
Signature flavour in German wheat beer and often found in ales and stouts Generally always an off flavour when it presents in lagers |
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Chlorophenol - flavour |
Antiseptic mouthwash, chlorine |
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Chlorophenol - origins |
Chlorinated water Inappropriate cleaners/sanitisers used like chlorine based bleached Contamination of water or packaging |
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Chlorophenol - confusions |
Guaiacol 4VG |
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Chlorophenol - comments |
Often described by consumers as “chemically” and has a high rejection from consumers There are more compounds than just 2,6-dichlorophenol but this is the one used as the aroxa standard |
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DMS - Flavour |
Sweet corn or Tomato juice |
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DMS - Chemical |
Dimethyl Sulphide |
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DMS - Origins |
Formed from malt derived precursors (SMM and dimethyl sulphoxide) during wort production and (but to a lesser extent) fermentation |
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DMS - comments |
Excessive levels are indicative of contaminant bacteria during fermentation Okay in some beers |
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Butyric acid - flavour |
Rancid, baby vomit |
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Butyric acid - origins |
Produced by bacteria during mashing and sweet wort separation Sugar syrup production Can be a result of spoilage in packages bacteria (anaerobic bacteria) |
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Butyric acid - confusions |
Isovaleric acid Ethyl butyrate |
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Butyric acid - comments |
Bacteria: Clostridium butyricum Flavour impact can be worsened by diacetyl Flavour intensity increases as beer pH decreases |
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Caprylic - Flavour |
Goat hair, soapy or candle wax |
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Caprylic - Chemical |
Octanoic Acid |
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Caprylic - Origins |
Produced by yeast during maturation and released from autolysing yeast cells |
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Caprylic - comments |
Desirable flavour note in some pale lagers. its a positive for flavour and mouthfeel (small amounts) Associated with traditionally produced lagers that have a prolonged maturation Sometimes found in lambics |
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Isobutyraldehyde - Flavour |
Grain, like germinating malt |
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Isobutyraldehyde - Origins |
Arises through use of pale malts and certain brewhouse procedures |
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Isobutyraldehyde - confusions |
Acetaldehyde Trans-2-nonenal |
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Isobutyraldehyde - comments |
Off flavour in low & non alcoholic beers signature flavour in some stouts, and componant of some lager and ale flavours Sulphur dioxie concentraion can influence the flaovur impact |
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Geosmin - flavour |
sugar beets or damp soil |
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Geosmin - Origins |
Contaminated brewing water Usually it is microorganisim growth in the water supply |
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Geosmin - comments |
Consumers are very sensitive to it and often decribe it as the beer smells dirt, earty, contaminated. water treatment should remove all geosmin |
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Ethyl Hexanoate - Flavour |
Apple, aniseed, Fennel Red apple Red Aftershock (unofficial) |
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Ethyl Hexanoate - Origins |
Produced by both ale and lager yeast. Amount depends on wort composition, yeast strain and fermentation conditions |
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Ethyl Hexanoate - Confusions |
Acetaldehyde Ethyl Butyrate Geraniol |
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Ethyl Hexanoate - comments |
Ester present in all beers but quantitys vary. key flavour impact in some lagers and ales Excessive concentrations are indicative of poor yeast handling |
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Ethyl Butyrate - Flavours |
Tinned pineapple or mango Papaya |
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Ethyl Butyrate - Origins |
Produced during fermination by both ale and lager yeast. Amount depends on wort composition, yeast strain and fermentation conditions Can be formed as a result of esterification of butyric acid thus ethyl butyrate can be indicatibe of brewhouse hygiene problem |
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Ethyl Butyrate - Confusions |
Butyric Acid Acetaldehyde Isonamyl Acetate |
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Ethyl Butyrate - Comments |
Pleasant tropical fruit flavour note to ales and lagers. (aroxa) Personally I don't find it that pleasant as in moderate to high quantities it can verge on vomit like (to me personally) |
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Ethyl Acetate - Flavours |
Nail varnish remover Pear drops (in smaller concentrations) |
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Ethyl Acetate - Origins |
Produced by both ale and lager yeast Wild yeast produce excessive amounts Stems from acetic acid |
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Ethyl Acetate - Confusions |
Acetaldehyde Ethyl Hexanoate Ethyle Butyrate |
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Ethyl Acetate - Comments |
Present in all beers, ales more so than lagers and gives a desirable "estery" impressions however in excessive amounts becomes unpleasant Strong ales in particular can have noticeable amounts |
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Vanillin - Flavour |
Vanilla, ice cream, custard |
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Vanillin - Origins |
Could be a number of origins Ageing on wood Addition of extracts Wild yeasts Breakdown of certain phenolic compounds during beer storage Charring of oak barrels breaks down lignins into phenolic aldehyde (vanillin) |
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Vanillin - confusions |
4 VG 2,3-Butanedione (diacetyl) |
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Vanillin - comments |
Generally a positive flavour Ales and stouts imparts a creamy aroma and can contribute to a smooth mouthfeel Can be foud as an ageing character in wheat beer and beers contaminated with wild yeast |
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Trichloroanisole - Flavours |
Musty, like corked wine or damp cellar 2,4,6-trichloroanisole |
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Trichloroanisole - Origins |
Often associated with use of recycled wood and cardboard.
The compound can migrate across packaging materials to contaminate raw materials, filter aids, and beer. Extremely active compound |
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Trichloroanisole - comments |
Consumers hate it and even low levels will be rejected as tasting "contaminated" Cork taint in wine Beers with corks are susceptible |
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Metallic - flavour |
Metal, blood, iron, ink |
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Metallic - Chemical |
Ferrous Sulphate |
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Metallic - origins |
Contamintion of beer with metal ions through raw materials or brewhouse corrosion Metallic odours can be produced by lipid oxidation |
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Metallic - confusions |
Sulphitic Citric Acid Trans-2-nonenal |
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Metallic - comments |
Affects mouthfeel, usually a horrid taste and can also be present in aromas Rub on back of your hand to check for aroma |
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Lactic acid - flavour |
Lactic. yoghurt, sour milk, sour |
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Lactic acid - origins |
Bacteria Intentional or contaminant |
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Lactic Acid - comments |
Often intentionally used in witbier, saison, lambic, flanders, American sour, Barrel-aged beer |
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Acetic - Flavour |
Vinegar |
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Acetic - Origins |
Produced by yeast during fermentation or acetic acid producing bacteria too much yeast growth, contamination and wild yeast can all result in excessive levels |
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Acetic - Confusions |
Citric acid Lactic acid Acetaldehyde |
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Acetic - Comments |
Present in all beers, it becomes an off flavour in high concentrations Characeteris of lambic, gueuze, flanders etc Common problem in draft dispense Intensity increases as the pH lowers |
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Ethyl phenylacetate - flavour |
Honey, sweet mead or sherry |
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Ethyl phenylacetate - origins |
Formed during beer ageing Tends to develop after the appearance of papery, tobacco, leather notes and after loss of bananan and bitter notes |
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Ethyl phenylacetate - comments |
Oxidation product, reasearch ont he compound still seems to be quite young Can be a positive note in honey beers |
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Sulphitic - flavour |
Struck match ot young white wine |
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Sulphitic - chemical |
Sulphur dioxide |
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Sulphitic - origins |
produced by lager yeasts (not ale) during fermentation. Can be added as an antioxidant |
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Sulphitic - confusions |
Dimethyl trisulphide H2S |
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Sulphitic - comments |
Sulphites keep beer fresh during storage and affect the flavour intensity of many beer aldehydes can impart a distinctive sulphury character to fresh beer about 1% of people are sensitive and may have allergic reactions to sulphites |
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Isobutylquinoline - flavour |
Leathery, like dry hay |
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Isobutylquinoline - origins |
precise origins unknown, we do know that it is formed during storage from precursors. It acts with outher compounds to give a "stale" off flavour |
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Isobutylquinoline - confusions |
Trans-2-nonenal Isobutyradehyde |
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Isobutylquinoline - comments |
Tends to appear appear after papery notes |
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Mercaptan - flavour |
Drains, rotting garbage |
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Mercaptan - chemical |
Methanethiol |
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Mercaptan - origins |
Yeast autolysis at the end of fermentation or during maturation. Can also be contributed by dry hopping and by growth of bacteria in beer |
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Mercaptan - Comments |
It is a component of the sulphury flavour character of beer and is found in all beer styles to a degrees Like ther thiols is becomes an off flavour when present to excess |
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Biscuity (2-acetyl pyridine) - Flavour |
Malty biscuity, like pale barley malt or malt dust |
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Biscuity (2-acetyl pyridine) - Origins |
formed during malt kilning. Becomes more prominent in beers contaminated with caustic cleaning agents |
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Biscuity (2-acetyl pyridine) - comments |
Present in all beers made with barley malt. desirable companent of many beers. present with many similar compounds which are responsible for the range of malty flavours |
