Trouble Shooter's Guide
The following off flavors are described in an effort to permit recognition and are followed by the reason that they may detectable. These characteristics are normally associated with failure to sanitize your equipment properly or to prevent re-contamination.
CIDERY/WINEY
a flavor sensation reminiscent to a wine or citrus character Use of household (cane) sugar as a source of fermentables Excessive use of corn sugar as a source of fermentables Fermentations at temperatures above 75 degrees. DIACETYL a flavor (off flavor) sensation associated with butter or butterscotch Certain yeast strains or unhealthy yeast Excessive use of corn or rice in mash Inadequate aeration of the wort prior to pitching the yeast Bacteria contamination High fermentation temperatures Fining before yeast has a chance to settle out DIMETHYLSULFIDE an off flavor sensation related to sweet corn or cooked cabbage Improperly stored malts, especially 6-row Short boiling time of the wort Bacteria contamination Extended lag time before yeast becomes active in wort ESTERY/FRUITY a flavor sensation related to fruits (bananas, raspberries, etc) Ale yeast High gravity worts Excessive aeration of the wort Pitching yeast at temperatures above 85 degrees Fermentation temperatures above 75 degrees Excessive amount of trub GRAINY a flavor sensation related to raw grain flavor Improper boiling Over cracking of malts or adjuncts Excessive amount of trub LIGHT STRUCK/SKUNKY an off flavor and/or smell sensation reminiscent to a skunk Use of old or improperly stored hops Exposure excessive sunlight or artificial light in glass carboy Beer bottled in clear or green glass bottles MALTY a smell or flavor sensation generally associated with malt High malt content Low use of bittering hops Crystal, munich or toasted adjuncts Low attenuation or unhealthy yeast High fermentation temperatures Fining before yeast has a chance to settle out Use of a brewpot made of aluminum, mild steel, cast iron Chlorinated tap water METALLIC an off flavor sensation relating coin-like or tinny Iron content in the water Use of a brewpot made of aluminum, mild steel, cast iron OXIDATION a smell and/or flavor sensation reminiscent to cardboard (also, winey, sherry-like) Excessive aeration (splashing) when siphoning or bottling Malfunctioning airlock or lack of water in the airlock Excessive storage in single stage plastic fermenter The addition of tap water (highly aerated) to finished beer Excessive air space in secondary fermenter Excessive air space in bottled beer Excessive aging of bottled beer Storage of bottles at excessively warm temperatures PHENOLIC an off flavor sensation reminiscent to medicine Wild yeast or bacteria contamination Boiling of adjunct grains Chlorinated tap water SOUR an off flavor sensation generally perceived on the sides of the tongue Bacteria contamination Excessive use of household sugar, citric acid or ascorbic acid. Excessive fermentation temperatures Use of wooden utensils in cooled wort (wood harbors bacteria) Inadequate sanitizing Storage of bottled beer at warm temperatures SULFUR a smell sensation reminiscent to rotten eggs Unhealthy yeast Yeast autolysis Excessive storage on yeast sediment YEASTY a smell or flavor sensation Use of unhealthy or non-beer (Baker's) yeast Yeast autolysis
SPECIAL THANKS TO THE AUTHORS OF ZYMURGY, THE COMPLETE JOY OF BREWING AND THE COMPLETE HANDBOOK OF BREWING
