20 common wine questions

by Tom Cannavan and Jonathan Hesford, 2012

Readers north of the border will know that I present a weekly wine slot on Scottish Television. An email to the studio came from a viewer who "followed my recommendations every week," and "had learned so much about wine," from watching the show. But she had been stumped by one comment I'd made about a 2009 Australian Shiraz, when I said that the 2008 vintage was also available in some stores. "What did Tom mean by 'vintage'?" asked the viewer.

My researcher on the show - a bright, knowledgeable, wine-loving young woman I've been working with for many months - passed the question on to me because she hadn't a clue herself: "What does vintage mean?" she asked. She was completely taken aback when I told her almost all table wines are the product of a single annual harvest, and the date of that harvest adorns the label.

When I recounted the story to a winemaking friend called Jonathan Hesford who currently makes wines at Domaine Treloar in the Roussillon, he expressed no surprise: "One of the commonest questions I'm asked on winery tours is what does 'vintage' mean," he told me, adding, "I should write a book with answers to the 50 most common questions: it makes you realise how much we take for granted about the average wine drinker's knowledge."

The book may appear one day, but meanwhile with Jonathan's help I have assembled the 20 wine questions most frequently asked by casual drinkers. Of course, wine-pages visitors will know most of the answers, but we've pooled our knowledge to give those too.

Q and A

1. How many harvests do you get a year?
Leaving the quirks of some vineyards planted in the tropics to one side, the answer is just one, starting around September in the northern hemisphere and March in the southern hemisphere. The harvest of fruit is gathered and taken to the winery, and the whole cycle begins again with the vine dormant over winter and bursting back into life in spring.

2. How much wine does a vine produce?
It depends on many factors including the vine's age, the variety being grown, the growing conditions, the style of wine being made and, importantly, the quality of the wine. The volume of fruit harvested is determined by natural factors and by the hand of the winemaker: removing bunches during the growing season concentrates the remaining fruit, and is a common practice for quality wines. It takes just over a kilo of grapes to produce enough juice for one bottle of wine, but depending on the factors above one vine might produce enough fruit for just a single bottle of high quality wine, or enough for several bottles.

3. What are sulphites?
Sulphites are organic compounds that occur naturally in grapes and many other fruits and vegetables. But sulphur dioxide is also added to wine as an anti-oxidant and anti-bacterial agent to prevent the wine from going off. The levels are extremely low, but some winemakers are trying to avoid adding extra sulphur dioxide, though this does run the risk of wines spoiling more quickly.

4. What does the year on the label mean?
This is the year in which the grapes were grown, not the year the wine was released. Almost all quality table wines are the product of a single year, though blending of two or more vintages is common in some wines like Champagne and Sherry, and in some inexpensive wines. A very few top-end wines are multi-vintage too, like Vega Sicilia's Unico for example.

5. When a label says it has "flavours of raspberries," have they added raspberry flavour?
No. These descriptive terms are just a way of trying to convey flavours and aromas in a wine that remind the taster of something.

6. What is tannin?
Tannin is a compound extracted from grapes skins, pips and stems and is most noticeable in red wines where there is most skin contact during winemaking. Tannin is also contributed from new oak barrels. The way the wine is made can influence how much tannin and other phenolic compounds (like colour pigment for example) is extracted from the grapes and ends up in the wine. Tannin is a preservative that enables wine to age and which gives a wine structure and texture. With age tannins become more rounded and polished.

7. What exactly are 'legs' and what do they tell you?
There's a common belief that 'legs' - the rivulets of wine that run down the inside of the glass after you swirl it - is an indication of alcohol level and quality, but it is not so simple as that. The cleanliness of the glass and the viscosity of the wine can also cause differences in the 'legs', so it is not a foolproof indicator of high alcohol or quality.

8. How do you know how long to lay down a wine and when is the best time to drink it?
That is a tough question and impossible to answer with a blanket definition. The vast majority of wines are made for immediate consumption, but will also be good to drink for a couple of years. In general, red wines age better than whites and certain grape varieties and wine styles age better than others: wines made from Cabernet Sauvignon and Port wines can be very long-lived for example. Whether such wines improve with age is a subjective opinion: older wines trade some of their fruit and vibrancy for developed flavours, and it is a trade-off that some like more than others. Jonathan also believes that traditionally made wines - made without too much technology - generally have a superior ageing capacity.

9. Should you always decant red wines?
It is rarely necessary to decant a red wine: in most cases you can simply open, pour and enjoy. But many people believe young wines that are very tight and appear 'closed' can benefit from being decanted and exposed to oxygen. Some older wines throw a sediment in the bottle which is unpleasant to drink, so decanting these off the sediment can make them easier to pour for guests.

10. At what temperatures should you serve red and white wines?
Again, few people will bother to measure temperature with a thermometer, but as a rule of thumb whites are often served too cold and reds too warm: many white wines, like serious white Burgundies, are best just very lightly chilled, whilst some reds - not just Beaujolais but bigger, more structured reds - can taste better if kept cool before serving. Sparkling wines should always be served well chilled. As a guideline, still white wines will show best around 7-9 degrees, and reds around 17-19 degrees Celsius.

11. How do you know a wine is "Estate Produced"?
That information is usually featured on the label, though sometime it needs a bit of de-coding! In classic French regions words like "Mis en Bouteille en Château" or "au Domaine" literally say the wine is 'estate bottled', whilst in Germany the word 'Erzeugerabfüllung' means much the same. In English-speaking nations the term "Estate wine" or, specifically, something like "Estate Chardonnay," is sometimes used. Champagne is a special case, where the code letters RM indicate the wine was made by a 'récoltant-manipulant', someone who grew the grapes and made the wine. 'NM' on the other hand, indicates 'négociant-manipulant', normally one of the big houses that has bought grapes and parcels of wine to make its production. Some regions have historically separated the farmers who grow the grapes and the technicians who make the wines, like Champagne, Rioja and Port for example. It is not necessarily an indication of inferiority that a wine is not estate bottled: many great wines are made from fruit purchased from expert growers.

12. Why are some wines not suitable for vegetarians?
Normally this is because of the agents that have been used to 'fine' or clarify the wine, which can be animal derived products like isinglass (from fish) or gelatin (which can be derived from animal bones). There are alternative fining agents like PVPP, a synthetic agent, and Casein which is made from milk (so not suitable for vegans). Vegetarian-suitable wines normally carry that information on the back label.

13. What kind of wines improve with age?
This is a big topic. Generally, only more expensive wines will age successfully: most wines costing less than £10 are made for short-term cellaring only. But this does not mean that all expensive wines are guaranteed to improve with age: that depends on many factors including the grape variety, the region where the wine was made, the style of wine, and crucially, how well it is stored. Traditionally, Cabernet Sauvignon-based wines from Bordeaux have improved with cellaring - the tannins have softened and the wines have become increasingly harmonious. Other Cabernet Sauvignon wines from elsewhere can be long-lived too, but sometimes wines made from much riper grapes in hotter climates, without the same levels of tannin and acidity, age a little less well for example. There is more information on this in our online wine course, part VI.

14. What makes a wine sweet?
There are a variety of methods for making sweet wines. These vary from cheap and easy (stopping fermentation with some sugar remaining and topping up with sweet grape juice), to some of the most labour intensive and expensive processes in the wine making world. At the other end of the scale, Botrytis cinerea, or 'Noble rot', is a fungus which can attacks grapes leaving the grapes shrivelled and unsightly, but tasting deliciously sweet and rich. Some of the world's greatest sweet wines including Sauternes from France and Trockenbeerenauslese from Germany are made with these grapes. Late harvest wines are made from grapes left on the vine long after they are ripe, the sweetness building into the late autumn. Icewines are an extreme form of late harvest, the grapes left on the vine into winter until they freeze. When crushed, the water content is dispelled as ice leaving a thick, lusciously sweet wine. Fortifying with spirit is another way to produce a sweet wine: fermentation converts sweet grape juice into dry wine by converting sugar to alcohol. But if you add spirit half way through, the fermentation stops, leaving lots of sugar behind. This is how sweet wines like Port, Rivesaltes and Australia's liquor Muscats are made.

15. How do you make rosé?
In Champagne it is allowed to mix some red wine with the white Champagne, but for almost all table wines rosé is just a light red wine: red wines take their colour from the skins of dark grapes during pressing and fermentation - the dark pigment is in the skins, not the grape juice. If you remove the skins from the press or fermentation tank after a short time and continue to ferment without them, then only a little colour is leached and the wine has many of the properties of a white wine. That's rosé.

16. What is the difference between Vin de Pays and Appellation Controlée?
Another big topic, but basically these are two French systems for classifying and controlling wine production. Traditionally Appellation Controlée (AC) was for the best quality wines of specified regions, and wine would only qualify if following strict rules imposed by the AC authorities. Many winemakers wanted to experiment, growing different grapes or making wines with different methods, which gave rise to a new geographical control and classification called Vin de Pays, which was more flexible. Though seen as a 'lesser' classification, VdP wines can be of very high quality and can be expensive. Recently, it has been annouced that Vin de Pays is being replaced with Indication Geographique Protégée (IGP).

17. Why do some wines give me a headache?
Clearly higher alcohol wines can be the source of this problem, but some people have a sensitivity to sulphur in wines, and yet others to histamines, which can be found in red wines in particular.

18. What does "corked" mean?
Not that there are little pieces of cork floating in the wine, but that the wine has been affected by a chemical called TCA (2,4,6-trichloroanisole). TCA can be created in a wine if there is a mould present on the oak tree bark used to make the cork, and can be detected as a musty smell and off-flavours. Many producers have switched to screwcaps and other synthetic closures mainly because of this problem.

19. What country produces the best value wines?
This is very difficult to say and depends a lot on interpretation. Quality-to-price ratio is all important: cheap doesn't necessarily mean good value, and some would argue that cheap wines are rarely good value. Certainly the lower cost of land and production in countries like South Africa, Argentina and Central European countries results in less expensive wines, but then the huge, automated wineries of Australia and California or the modern facilities in France's Languedoc or Spain's La Mancha allow them to compete head on too.

20. How much wine constitutes a 'unit' of alcohol?
It's a common misconception that one glass of wine equals one 'unit'. The unit in which alcohol is measured for those advocating healthy consumption is actually 10 millilitres of pure alcohol. So to work out how many units are in a glass requires you to know how much alcohol is in the wine, and how much wine is in the glass. For example, a 'large glass' is commonly 250 millilitres. If it is a wine with 14% alcohol, it actually contains 3.5 units, not one: the formula is millilitres of liquid (250) x alcohol (14) divided by 1000.