What if we told you the best wines available were simply ones that you enjoy drinking? We fill your glass to the brim with wine facts that will have you questioning everything you knew about this delightful drop. A Charles Sturt University wine expert pops the cork on the science, social practices and myths about vino.
By Professor of Oenology Leigh Schmidtke in the Charles Sturt’s Gulbali Institute for Agriculture, Water and Environment.
Why do I get a hangover? And why do some people cope better than others?
Wine has many different chemicals that illicit a physiological response in people. Important chemicals in wine are ethanol and sulfur dioxide. Ethanol is derived from the yeast during fermentation of sugars in grapes and sulfur dioxide is added in small quantities to act as a preservative.
Both ethanol and sulfur dioxide may contribute to the feelings of a hangover if consumed in excessive quantities. Some wine, especially red wines, also have microbially produced chemicals that act like histamine which can also cause people to react.
Our body detoxifies ethanol by making acetaldehyde, which causes a headache. Some people are more able to cope with acetaldehyde than others, so there is a high level of variation in how wine consumption impacts our physiology.
Regular consumption of wine also induces a higher level of expression of the enzymes responsible for metabolic processing of ethanol, which also creates a degree of tolerance in those people.
What is a quality wine?
Wine is made from grapes by a process called fermentation, which produces ethanol. Wine is typically about 85 per cent water, nine to 14 per cent ethanol and the remaining portion a mix of organic acids, tannins, phenolics, volatiles and non-volatiles components all derived from the grapes, or from oak.
The most important aspect of quality is ‘do you like the wine?’ If you do like it, then it’s a good wine.
The ‘art’ in making a refined wine is to create a beverage that has balance between the flavour and textural components, with length/persistence of flavour, absence of faults – all are important.
Wine is made from fruit so the first flavour should be fruitfulness. Fruit flavours may change during the cellaring of the wine, but they are the most important flavour components.
Even as the wine ages, fruit flavours will develop and change but all other components of the wine (oak, acidity, sweetness, tannins, phenolics etc) should be present as a support structure to complement fruit flavour.
As consumers become more experienced in wine tasting, we more frequently look for a breadth and flavour and complementary structural components rather than intensity of a single character in the wine.
I don’t ‘speak wine’. Can you explain what some of the wine terms mean, for example, dry, bold, balanced, heavy, light, what gives a wine texture, dry wine vs sweet?
Dry wine is a wine that has had all fermentable sugars converted to ethanol, whereas a sweet wine will still have some fermentable sugar remaining. Some sweet wines may be high in acidity as well but the sugar balances this on the palate.
Typical wine grapes destined for dry table wines at harvest will have around 210- 240 grams (g) of sugar per litre before fermentation, which produces roughly 12 to 14.5 per cent ethanol. The level of acid in wine grapes for dry table wine can vary considerably as well from 3-4 grams per litre (g/L) and pH 4 to around 6-7 g/L and pH 3 (where pH is a measure of the strength of those acids).
As grapes mature, they increase in fermentable sugar concentration and decrease in acidity. Striking a balance between sugar, acidity and fruit flavours in the grapes at harvest is the key to making good wine. It’s part art and part science.
The interaction of tannins/phenolic compounds with salivary proteins to create a dry sensation in our mouth. Red wines will have tannins and are more likely to produce a drying texture in the mouth compared to white wines.
A bold wine may be a wine with intense fruit flavour or taste. These wines may have intensity but sometimes lack balance or breadth of flavour.
A complex wine will have a broad spectrum of flavours and mouthfeel attributes and are typically not bold wines as there are numerous subtle interactions of acidity, palate weight, flavour and aromas coming together.
How does the growing region contribute to the type or quality of wine?
This depends on the grape variety and targeted wine style.
Generally, cooler regions are best for higher quality grapes with full flavours, providing sufficient temperature accumulation can be achieved to ripen the grapes.
However, there are some excellent wines made from warm to hot regions as well. It’s all about matching the grape variety and wine making inputs to wine styles that are suitable for the climate in which the grapes are grown.
Each variety has an optimum temperature band for ripening. Matching the variety of grape to a climate is one of the important aspects of ‘terroir’.
Australia has some of the oldest continually cultivated grape vines in the world. Having said that, we are considered one of the New World producers, with Old World (European) producers being France, Italy, Spain, and Georgia, which have with hundreds of years of wine making heritage.
What’s the best way to store wines for longevity? Does wine go off once you open the bottle and should I decant my wine?
Wine should be stored at a constant temperature (16 to 18 degrees C) and humidity (65 per cent). These are ideal storage conditions, but many people cannot achieve that.
It is best to store wine bottles in the coolest spot in the house free from temperature fluctuations. This is often in the middle of the house, away from external walls.
It needs to be kept away from light, vibrations and consumers. If you are a serious collector, you can buy a wine fridge.
Most Australian wine is now sealed in a bottle with a screw cap. These caps are excellent at ensuring zero to very low levels of oxygen permeate through the cap wadding that ensures the wine matures according to the intentions of the wine maker.
Bottles with screw caps don’t need to be horizontal; although this may be a convenient way to store lots of wine.
Bottles with cork closures should always be left on their side to ensure the cork remains moist and provide the best opportunity for the wine to age gracefully.
There are specialised ways to store wine for a few days once it’s been opened. Pour it into a smaller bottle and put the cap on to reduce the head space of the wine. This will keep the oxygen levels as low as possible and prevent oxidation reaction occurring that rob the wine of fruit flavour.
After wine is open there are a range of chemical reactions that occur that lead to diminished wine quality if the wine is left exposed to the air. Chemical reactions speed up or slow down, according to temperature.
Once opened, it is recommended keeping the bottle in the fridge for no more than three days.
Decanting wine infuses it with oxygen and allows wine to open up and be expressive. This is more important for red wines with age than white wines.
What wines typically last longer/are good for ‘birth year wines’?
‘Birth wines’ are usually more expensive wines that last longer. Vintage ports, which are made to be aged in a bottle, make excellent birth wines if you are unsure of what other wines to buy.
Ultra-premium table wines may also be good for birth year wines – generally you will get what you pay for so if it is for a special person, don’t skimp.
What are the potential impacts of climate change on the wine industry?
Climate change is one of the most impactful external stimuli in the wine industry.
The ideal environment for wine making is temperate, cool areas, although there are many excellent wines made in warm to hot regions. To match climate and temperature for wine grape growing producers can either seek altitude (further up the mountain) or latitude, by moving further south or further north depending on which hemisphere a wine maker is in.
Climate change is already impacting the wine producing geography of the world. The most likely outcome for existing wine regions is that wine styles will evolve.
Existing wine making regions will always be important but new regions will become fashionable, especially those in cooler regions. Different varieties will be planted that are suited to changing climates and new wine styles will be made.
Explain why the wine industry is a fashion industry and why people collect wine?
The wine industry is every bit a fashion industry as it is a beverage industry. Consumer-preferred wine styles evolve according to many factors, including wine writer’s perceptions of quality. Just as we don’t want to wear the same clothes every day, most people don’t want to drink the same wine every day either.
Wine is a living beverage, it changes according to age. People collect and store wines to reflect on how the wine changes over time.
What are the best wines?
The best wines are the ones you like – regardless of other people’s opinion.
For me, the best wines have balance and they aren’t dominant in a single flavour or sensory attribute.
It’s important to not get hung up on what is right or wrong when consuming wine. Wine is a social beverage and it is best enjoyed sharing the occasion with people you enjoy being with.
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