2-bromophenol
“Bromophenol , inky, like a museum or old TV set”
Technical specification
Assessment
Without covering the glass, swirl the beer to release the aroma. Take a single short sniff. Repeat as necessary. Amount of flavour per capsule
3.9 µg Threshold
100 ng / l in cider Origins
Bromophenols can taint product through contaminated ingredients or packaging. Associated with use of recycled wood and cardboard. Can arise due to growth of Alicyclobacillus prior to fermentation. Importance
Imparts an unpleasant note, described by consumers as ‘chemical’ or ‘contaminated’. Often associated with the presence of guaiacol when produced as a result of bacterial spoilage. CAS registry number
95-56-7 Other names
bromophenol
o-bromophenol
ortho-bromophenol
Remarks
Bromophenolic taints can be caused by several compounds, of which 2-bromophenol is only one. The flavour produced by this compound is typical of the group. Threshold distribution
2,6-dichlorophenol
“Chlorophenol , like antiseptic mouthwash”
2,6-dichlorophenol
1.0 µg
Technical specification
Assessment
Without covering the glass, swirl the beer to release the aroma. Take a single short sniff. Repeat as necessary. Amount of flavour per capsule
1.0 µg Threshold
300 ng / l in cider Origins
Formed by admixture of incompatible cleaning agents or by contact of cider with chlorinated water. Occasionally arises through contamination of processing aids or packaging materials. Importance
Taint in cider. Associated with a high degree of consumer rejection, even at low levels. Often described by consumers as ‘chemical’, ‘antiseptic’ or ‘contaminated’. CAS registry number
87-65-0 Other names
1-hydroxy-2,6-dichlorobenzene
2,6-DCP
2,6-dichlorfenol
Remarks
Chlorophenolic taints can be caused by several compounds of which 2,6-dichlorophenol is only one. The flavour produced by this compound is typical of the group. Threshold distribution
dimethyl sulphide
“DMS , like sweetcorn or tomato sauce”
Technical specification
Assessment
Without covering the glass, swirl the beer to release the aroma. Take a single short sniff. Repeat as necessary. Amount of flavour per capsule
150 µg Threshold
30 - 50 µg / l in cider Origins
Contaminant introduced through use of insufficiently-purified carbon dioxide for carbonation. Can also arise through microbiological growth during fermentation. Importance
Imparting a sweetcorn-like, sulphury note, DMS can also be indicative of contamination of the process with bacteria. Indole and skatole may also be found in ciders in which DMS has been produced by bacteria. CAS registry number
75-18-3 Other names
DMS
dimethyl monosulfide
methylsulfanylmethane
methyl monosulfide
methane thiomethane
methyl sulfide
methyl thioether
methylsulfanylmethane
2-thiapropane
thiobis(methane)
thiobismethane
Remarks
The perception of dimethyl sulphide is influenced by the presence of aromatic higher alcohols such as 2-phenylethanol which can be present at high concentrations in some ciders. Threshold distribution
ferrous sulphate
“Metallic , like ink or blood”
Technical specification
Assessment
Take a little beer into your mouth. Move it around with your tongue for a few seconds then swallow it. To confirm, rub a little of the beer onto the back of your hand and check for metallic odour. Amount of flavour per capsule
8.2 mg Threshold
2.7 mg / l in cider Origins
Derived from contamination of cider with metal ions, either from raw materials or from corrosion of factory equipment. Importance
Taint and occasionally off-flavour in cider. Primarily affects cider mouthfeel but occasionally product odour can also be affected. CAS registry number
7782-63-0 Other names
ferrous sulfate
iron(2+) sulfate
iron(2+) sulphate
ferrous sulphate heptahydrate
ferrous sulfate heptahydrate
iron(2+) sulfate heptahydrate
iron(II) sulfate heptahydrate
iron(II) sulphate heptahydrate
Remarks
Copper, manganese and tin can also generate metallic notes in cider. Occasionally, the presence of lipid oxidation products in cider can give rise to ‘non-metallic’ metallic odours. High concentrations of such metal ions are also associated with development of hazes. Threshold distribution
geosmin
“Geosmin , like sugar beets or damp soil”
Technical specification
Assessment
Without covering the glass, swirl the beer to release the aroma. Take a single short sniff. Repeat as necessary. Amount of flavour per capsule
70 ng Threshold
20 ng / l in cider Origins
Imparted through use of tainted fruit. Dirty filter pads have also been implicated in development of such flavours. Source of the taint is growth of Actinobacteria or certain fungi (including Botrytis and Penicillium ). Importance
Imparts an undesirable earthy note to cider which is reminiscent of sugar beets or damp soil. Associated with a moderate degree of consumer rejection. Often described by consumers as ‘dirty’ or ‘contaminated’. CAS registry number
23333-91-7 Other names
2beta,6alpha-dimethyl bicyclo(4.4.0)decan-1beta-ol
octahydro-4,8a-dimethyl-4a(2H)-naphthol
2b,6a-dimethyl bicyclo[4.4.0]decan-1b-ol
2beta,6alpha-dimethyl bicyclo[4.4.0]decan-1beta-ol
1,10-(E)-dimethyl-(E)-(9)-decalol
(E)-1,10-dimethyl-(E)-decalin-9-ol
2b,6a-dimethyl bicyclo(4.4.0)decan-1b-ol
2,6-dimethyl bicyclo(6.4.4.06)decan-1-ol
4,8a-dimethyl decalin-4a-ol
4,8a-dimethyl-1,2,3,4,5,6,7,8-octahydronaphthalen-4a-ol
octahydro-4,8a-dimethyl-4a(2H)-naphthalenol
octahydrodimethyl-4alpha-naphthol
Remarks
Associated with poor factory hygiene. Attention to cleaning and sanitation, with particular emphasis on water treatment practices, such as carbon filtration, should keep this flavour under control. Threshold distribution
p -menthane-8-thiol-3-oneCatty, like blackcurrant juice or tom cat urine - full
p -menthane-8-thiol-3-one
p -menthane-8-thiol-3-one1.9 µg
Technical specification
Assessment
Without covering the glass, swirl the beer to release the aroma. Take a single short sniff. Repeat as necessary. Amount of flavour per capsule
1.9 µg Threshold
1.9 µg in cider Origins
Catty flavour arises due to contamination of juice with precursor materials. For example, H2 S produced during fermentation reacts with mesityl oxide to produce a catty note. Importance
Imparts an undesirable odour to cider, reminiscent of tom cat urine. Mesityl oxide contamination can arise from contact of raw materials with painted surfaces or plastic coatings. The presence of solvent materials such as acetone can also be associated with such problems. CAS registry number
38462-22-5 Other names
para-mentha-8-thiol-3-one
buchu mercaptan
mangone
buchu ketone
2-(1-mercapto-1-methyl ethyl)-5-methyl cyclohexan-1-one
8-mercapto-para-menthan-3-one
8- mercapto-para-menthane-3-one
mercaptoisopropyl-5-methyl cyclohexanone
5-methyl-2-(2-sulfanylpropan-2-yl)cyclohexan-1-one
pulegone mercaptan
ribes mercaptan
thiomenthone
Remarks
A range of compounds impart catty characters to cider. The specific compound depends on the source. The compound used in this flavour standard is representative of the flavour of such compounds. Threshold distribution
2,4,6-tribromoanisole
“Musty , like corked wine with a rubbery overtone”
2,4,6-tribromoanisole
900 ng
Technical specification
Assessment
Without covering the glass, swirl the sample to release the aroma. Take a single short sniff. Repeat as necessary. Amount of flavour per capsule
900 ng Threshold
<10 – 500 ng / l in cider Origins
Contaminates product through ingredients, water, air, filter materials or packaging materials. Associated with use of recycled materials such as wooden pallets and cardboard. Importance
Imparts an unpleasant musty odour which is reminiscent of damp cellars or corked wine. This is one of the few flavours that can taint products through airborne contamination, even after the product has been packaged. CAS registry number
607-99-8 Other names
tribromoanisole
TBA
1,3,5-tribromo-2-methoxybenzene
methyl 2,4,6-tribromophenyl ether
Remarks
Derived from methylation of bromophenols by moulds. 2,4,6-Tribromoanisole is one of several bromoanisoles. The flavour produced by this compound is typical. It can be detected at concentrations well below the recognition flavour threshold. Threshold distribution
2,4,6-trichloroanisole
“Musty , like corked wine or a damp cellar”
2,4,6-trichloroanisole
580 ng
Technical specification
Assessment
Without covering the glass, swirl the sample to release the aroma. Take a single short sniff. Repeat as necessary. Amount of flavour per capsule
580 ng Threshold
10 – 200 ng / l in cider Origins
Contaminates product through ingredients, water, air, filter materials or packaging materials. Associated with use of recycled materials such as wooden pallets and cardboard. Importance
Imparts an unpleasant musty odour which is reminiscent of damp cellars or corked wine. This is one of the few flavours that can taint products through airborne contamination, even after the product has been packaged. CAS registry number
87-40-1 Other names
methyl 2,4,6-trichlorophenyl ether
1,3,5-trichloro-2-methoxybenzene
TCA
Remarks
Derived from methylation of chlorophenols by moulds. 2,4,6-Trichloroanisole is one of several bromoanisoles. The flavour produced by this compound is typical. It can be detected at concentrations well below the recognition flavour threshold. Threshold distribution
