Chapter 16

Wine Faults and Flaws

(book excerpts)

A wine fault is a major problem which is caused by sufficient concentration of a component that seriously reduces wine quality up to a point where the wine is undrinkable. Wine faults are either chemical or microbiological in nature and some are so severe as to strip the wine of all semblance of quality or even drinkability. For instance, ethyl acetate is the major ester produced by yeast and at low levels can contribute fruity aroma properties and add complexity to wine, but if the concentration is too high it has a perceived odor of nail polish. Wine flaws are minor attributes that depart from what are perceived as normal wine characteristics. These include excessive sulfur dioxide, volatile acidity, Brettanomyces or Brett aromas and diacetyl or buttery aromas. The amount to which these aromas or attributes become excessive is dependent on the particular tastes and recognition threshold of the wine taster. Generally, a wine exhibiting these qualities is still considered drinkable by most people. Many of the possible faults and flaws appear during the wine production process and can be prevented or corrected at the appropriate time, but others may manifest themselves only when the wine is in the bottle and sometimes years after bottling. The issue as to whether an individual wine is faulty (showing one or more serious defects), flawed (showing minor defects), or sound is not necessarily straight forward. Apart from the matter of a taster's individual perception thresholds, there can also be dispute as to whether a particular characteristic is, or is not, a fault or flaw. For example, the presence of Brettanomyces in a wine, many producers and critics claim it can, at low levels, add complexity, while purists perceive it always to be a fault. Detailed below are some of the most common faults and flaws encountered in bottled wine.

Click on the following topics for more information on wine faults and flaws.

Topics Within This Chapter:

  • Causes of Wine Faults and Flaws
  • Wine Hazes and Deposits
  • Metal Haze
  • Protein Haze
  • Phenolic Deposits
  • Tartrate Deposits
  • Microbiological Hazes and Deposits
  • Wine Color
  • Browning
  • Prevention and Treatment
  • Pinking in White Wines
  • Prevention and Treatment
  • Wine Aroma and Flavor Descriptors
  • Bareroot, Turnip, Earth
  • Barnyard-Like, Horsey, or Horse Blanket
  • Prevention and Treatment
  • Bitterness or Astringency
  • Buttery
  • Clovelike
  • Cork Taint
  • Prevention and Treatment
  • Fatty Mouthfeel
  • Gas/Spritz
  • Geranium
  • Green Bell Pepper
  • Green Flavors
  • Prevention and Treatment
  • Mousiness
  • Nail Polish, Solvent, Glue
  • Phenolic, Medicinal, Pharmaceutical
  • Sherry, Cut Apples, Nuts
  • Prevention and Treatment
  • Smoke Taint
  • Prevention and Treatment
  • Sulfur Taint
  • Hydrogen Sulfide
  • Mercaptans
  • Disulfides
  • Prevention and Treatment
  • Volatile Acidityr
  • Prevention and Treatment
  • Biogenic Amines in Wines