OFF FLAVOURS

Metallic

• Is very difficult to detect• Is much easier to taste than to smell

• Easy trick– Make a fist and rub the beer on the base of thumb

where it meets your forefinger

Phenolics

• Chemical compound is 4-vinylguiacol• Most often smells like cloves

• Comes from removing C02 from ferulic acid which is found in the cell wall of cereals

Sour (Acidic)

Results because of low pH• Darker malt = lower pH• Higher calcium= lower pH• Vigorous and extensive

fermentation = lower pH• Bacteria present = lower pH

• pH < 4 – sharper, increased dryness

• pH < 3.7 – metallic finish

• High bicarbonate = high pH• High malt bill = higher pH• High gravity = higher pH

• pH > 4.4 – soapy, caustic, biscuit & toast finish

Off Flavours

DMS

• Comes from an amino acid in malted barley• With longer germination times, the kernel

becomes more sensitive to heat• This is more readily seen in lighter malts such

as pale malt and pilsner malt

Off Flavours

Off Flavours

Off Flavours

Acetaldehyde

• Produced my yeast• Comes in the later stages of sugar break down• It is the immediate precursor of ethanol– This is the result of poor performing yeast

Off Flavours