Identifying Wine Faults
or
What I DON’T want to smell in my wine
By Lisa Jones
lisa.jones@vincor.ca
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Overview
• Sensory detection of Wine Faults
• Most Common Wine Faults
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Sulphurous Compounds
Lactic Acid Bacteria
Brettanomyces
Yeast Autolysis & Wild Yeasts
Oxidation
Environmental
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Sensory Evaluation
#1 Smell
• 80-90% of perceived taste is actually smell.
The tongue only tells us:
salty, sweet, sour, bitter or umami
Try this out –close your eyes, take
a candy, plug your nose and
taste. Try and guess what it is.
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Sensory Evaluation
#2 Appearance
-Watch your wine – there are some very
obvious problems, but what may seem like a
wine that’s not clearing - turbidity or cloudiness
could also be an indication of infection.
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“Why does my wine smell like bacon?”
• It cannot be stressed enough –
Good cleaning and sanitation will prevent
most of the wine problems.
• Basics – Cleaning (Saniton, Sanibrew, Microzyme, PBW)
– Cleaning- To remove visible and/or invisible grime, soil,
grease, fats,etc. from surfaces that come in contact with
wine.
• Basics – Sanitation (Potassium Metabisulfate, Iodofor, Sanibrew)
– Required step that ensures product contact surfaces are
free from microbial growth, eliminates potential spoilage
organisms. Not a substitute for cleaning or poor cleaning
– you can’t sanitize a dirty surface.
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“Why does my wine smell like bacon?”
• Inspect Fermenters, hoses, bottle fillers for cracks,
chips, excessive staining, etc. Don’t be hesitant to
retire equipment.
• Be cautious of any used equipment.
• Consider all contact points and times - filter plates,
bottle filler nozzle, overflow tub, etc.
• Insist on clean bottles – when a consumer has some
good and some bad bottles – contamination
occurred during bottling or is from the bottles.
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Sulfur
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Sulfurous Compounds
• Sulphur Dioxide - SO2
– Symptoms: Matchsticks or burnt rubber
– Cause: Over-sulphiting grapes, must or wine
– Resolution: Keep good records – don’t over sulfite
• Hydrogen Sulfide - H2S
– Symptoms: Rotten eggs
– Cause: Stressed yeast/struggling fermentation
– Prevention: Ensure must has enough nutrients and is in
acceptable temperature range (most yeast 65-80°F/1825°C)
– Resloution: Aerate wine when smell is first noticed –
splash rack. H2S can be removed with Bocksin or Copper
(Copper Sulfate or other)
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Sulfurous Compounds, cont.
• Mercaptans
– Symptoms: Onion, garlic or skunk
– Cause: Hydrogen Sulfide left untreated
– Treatment: Ascorbic acid, Deodorizing Carbon
filtration, etc.
• Dimethyl Sulfide
– Symptoms: Cooked cabbage
– Cause: Oxidized Mercaptans
JUST AVOID THIS!
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Lactic Acid
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Lactic Acid aka. Lactobacillus
MLF What is it?
Used in commerical wines to create buttery esters
and flavour components. Great, but uncontrolled
bacteria can cause wine to go off.
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MLF Faults
• MLF in the bottle
– Symptoms: Spritz, turbidity, musty, stale dishcloth
– Prevention: Add sulfides to avoid unintentional MLF
• Geranium Taint
– Symptoms: Smell of rotten geranium leaves
– Cause: Lactic Acid Bacteria and Potassium Sorbate
– Prevention: Do not treat wine that have undergone MLF with
Potassium Sorbate. Don’t do MLF to kit wines.
• Graisse
– Symptoms: “Ropiness”, slimy or fatty mouth feel, egg white
– Cause: Lactic Acid infection creating dextrins and polysaccharides
– Prevention: Use only commercial sources of lactobacillius
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Brettanomyces
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Brett – friend or foe?
• Cause: one of nine wild yeasts present in
every wine region in the world
• Symptoms: Barnyard, antiseptic, bacon,
sweaty saddle, wet dog, mousy, metallic as
well as sediment and carbonation
– At lower levels is complexity and not a “fault”
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Prevention of Brettanomyces
• Cleanliness
• Know your barrels – sometimes the best use is
as a planter
• Proper levels of SO2 in wine
• Keep wines topped up
• Cross contamination – Brett spreads easily
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Candida
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Pichia
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Yeast
• Wild Yeast (Candida, Pichia)
– Symptoms: Sherry-like, oxidized flavours, film on wine –
called “flor” yeast or “flowers of yeast”
– Prevention: Always inoculate with a wine yeast or culture
– do not leave it to chance. Minimize ullage - top up wines,
spray surface with SO2
• Yeast Autolysis
– Symptom: yeasty, brothy, meaty, rubbery, fatty
– Causes: wine left on lees and cells to break down, done
intentionally to create depth of flavour in some wines “champenoise” method of making sparkling wine.
– Prevention: Get wine off lees after fermentation is
complete
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Oxidized
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Oxidation
The most common wine faults as the presence of oxygen
and a catalyst are the only requirements for the
process to occur. Oxidation can occur throughout the
winemaking process, and even after the wine has been
bottled.
• Processing Oxidation
– Symptoms: raisin, caramel, nutty, cough syrup, orang-ish
brown colour of reds, dark golden white wines
– Causes: wine left in primary too long, carboy left not topped
up, wine not sulfited
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Cork Taint
• Cork taint is a wine fault mostly attributed to
the compound 2,4,6-trichloroanisole (TCA) As
cork taint has gained a wide reputation as a
wine fault, other faults are often falsely
identified as it.
– Symptoms: earthy, mouldy, and musty aromas in
wine that easily mask the natural fruit aromas
– Causes: TCA most originates as a metabolite of
mould growth on chlorine-bleached wine corks
and barrels
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Storage Problems
• “Cooked Wine”/Maderized
Wines exposed to extreme temperatures will thermally
expand, and may even push up between the cork and bottle
and leak from the top. Even if the temperatures do not reach
extremes, temperature variation alone can also damage
bottled wine through oxidation.
– Symptoms: corks pushing out of bottles, rim of red wine around cork,
prune, stewed flavours, oxidized compounds
– Causes: overly hot storage area
• Light Struck Wines
– Symptoms: cardboard or wet-wool flavour
– Causes: wine exposed to ultra-violet light
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Oxidation, cont.
• Ethyl Acetate
– Symptoms: nail polish, glue, varnish, fake fruit
– Causes: spoilage causing bacteria
• Acetyl Aldehyde
– Symptoms: sherry, green apple, sour, metallic
– Causes: spoilage causing bacteria
• Actetic Acid
– Symptoms: vinegar
– Causes: spoilage causing bacteria
CLEANLINESS IS NEXT TO GODLINESS.
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Sediment
• Re-fermentation
– Symptoms: carbonated or “spritzy” wine,
sediment, dry when it should be sweet.
– Causes: Not adding (or not adding enough)
Potassium Sorbate to a wine that has had sugar or
sweetener added, incomplete alcoholic
fermentation.
– Prevention: If adding less than 1 ¼ cup wine
conditioner add 2 teaspoons potassium sorbate.
– NOTE: some believe it adds a “bubblegum” flavour
to wine if too high a dosage is added.
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Sediment, continued
• Tartrate Crystals (aka wine diamonds)
– Symptoms: clear or sometimes bown, crystaline
deposits on bottom of the bottle or on cork, may be
mistake for glass. More likely to occur with wine
stored in cold location.
– Causes: Tartaric acid crystallization is a natural
process that occurs over time when the salts of
tartaric acid and potassium salt form.
– Prevention: Cold stabilization or addition
of metatartaric acid to temporarily keep
crystals in suspension.
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So one last time…
• PLEASE..
Clean and Sanitize
• Questions??
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