D1 Faults Flashcards
Detailed information about faults found in wine.
List 9 major faults found in wine today.
- Cloudiness / hazes;
- Tartrates;
- Refermentation in the bottle;
- Cork taint;
- Oxidation;
- Volatile acidity;
- Reduction;
- Light strike;
- Brettanomyces.
Give four reasons wine can be cloudy / hazy after bottling.
- Growth of yeast or bacteria;
- Failure to filter (or the wine was filtered inadequately);
- Wrong type of fining agent was used;
- Wine was over-fined, causing the remaining proteins in the wine to become unstable.
Name five ways to avoid cloudiness / haze in a finished wine.
- Improve hygiene in the winery;
- Pre-bottling chemical analysis;
- Proper filtering;
- Use correct fining agent;
- Not over-fining.
Why are tartrates seen as a fault to some wine drinkers?
Even though tartrates are completely harmless and naturally precipitate out of wine when it is held at a sustained cool temperature, tartrates look like foreign objects in the wine, namely shards of glass or large sugar crystals, which puts off some wine drinkers.
If you opened a wine that has a slight prickle or spritz to it which the wine isn’t supposed to have, and the wine is also kind of cloudy, what’s happening to the wine?
It’s refermenting – the winemaker failed to stabilize and clarify/filter the wine adequately.
How does cork taint present itself in wine?
- Smells like wet, moldy cardboard;
- Reduces fruit character on the palate;
- Makes a wine’s finish shorter.
How does oxidation present itself in wine?
- Wine turns brown prematurely;
- Loss of primary fruit;
- Vinegary smell.
Give three main reasons why wines suffer from oxidation in the bottle.
- Faulty bottling;
- Poor-quality corks or plastic closures;
- Keeping wine for too long when it doesn’t have the quality to age.
All wines have some level of volatile acidity but excessive amounts give a pungent smell of ____ and/or ____.
Nail polish remover and/or vinegar
What causes volatile acidity to become a fault?
- Active acetic acid bacteria;
- Inadequate levels of SO2;
- Excess exposure to oxygen.
Name five ways to avoid volatile acidity from becoming a fault.
- Sorting fruit to exclude damaged grapes;
- Meticulous hygiene in the winery;
- Keeping vessels topped up;
- Careful racking (to avoid excessive exposure to oxygen);
- Maintaining adequate SO2 levels.
What are some odors associated with reduction when it’s considered a fault?
- Onion;
- Rotten eggs.
What are some odors associated with reduction when it’s not considered a fault?
- Struck match;
- Smoke.
What are reductive odors caused by?
- High levels of volatile, reductive sulfur compounds that are produced by yeast under stress (due to low nitrogen levels) during winemaking;
- Near-anaerobic environments (no oxygen) during aging in closed vessels, especially during lees aging;
- Sometimes these odors evolve when wine is closed with the impermeable type of screw cap.
Name three ways to avoid reduction in wine.
- Ensure yeast has sufficient nutrients and oxygen during the winemaking process;
- Ensure the must is at an adequate temperature;
- SO2 may need to be lowered, especially if the closure to be used allows very little oxygen ingress.
What causes light strike?
What does this fault smell like in wine?
- Caused by UV radiation and certain wavelengths of visible light that react with certain compounds in the wine to form volatile sulfur compounds;
- Smells like dirty drains and other sulfuric compounds.
What are three ways to avoid light strike?
- Don’t leave wine in direct sunlight;
- Don’t store wine near fluorescent lighting for extended periods;
- Bottle wine in dark green and brown glass (wines in clear glass are most likely to be affected).
Brettanomyces, which some wine drinkers say can add to a wine’s complexity, becomes a fault when its off-odors dominate a wine.
What does the wine taste like when Brettanomyces is considered a fault?
- The wine’s fruity flavors are diminished;
- The acidity and tannins become more prominent;
- Overbearing notes of animal and farmyard smells.
Name four ways to avoid Brettanomyces becoming a fault.
- Meticulous hygiene in the winery;
- Maintaining effective SO2 levels;
- Keeping pH levels low;
- Keeping the time between the end of alcoholic fermentation and malolactic conversion as short as possible so that SO2 can be added.
