I used to think I knew a fair bit about wine. Lord knows I consume enough of the stuff to have a PhD in wine drinking, but unfortunately that’s not a real qualification and if it was, the job market would be so saturated I wouldn’t stand a snowball’s chance in hell of employment.
I did serve time in an Italian restaurant while studying, so I learned about the different kinds of wine, the cultivars of grapes used to make wine and how to pair them up with food. I also built a wine rack with the help of my father, which now serves as a particularly ugly bookshelf. Around the same time, I bought myself a John Platter guide, which provides a comprehensive list of all the South African wineries along with a description and rating of their annual repertoires. A one star wine is good to poach your pears in, but a five-star wine is a sure-fire way to impress your date.
And so, you see, the wine rack (perpetually empty), the restaurant education, the dedication to wine drinking and the John Platter guide really imbued me with the sense of wine wisdom. That is, until I started reading up about wine making. You would never guess just how intricate the process involved is and the degree of fine chemistry that goes into making a good glass of vino. It’s all about balancing acids, exploiting the biology of fungus and harnessing the power of organic chemistry.
Naturally, I decided to write a blog about the magical science that brings us wine!
Why? Because, shut up! No one ever needed a reason to talk about wine.
How to Make Alcohol (You’re Welcome)
There are two extremely good reasons why prison guards are constantly busting inmates for bootlegging liquor. (1) After a day dodging molestation and staring at whitewashed brick walls, alcohol must seem like the elixir of the Gods, and (2) alcohol is ridiculously easy to make. It’s a simple one-liner chemistry equation that requires ingredients you could find in even the most basic of kitchens: Sugar, water and yeast.
Yeast is a tiny, tiny fungus that uses sugar, also known as glucose, to grow. It’s what we use to make breads rise and it’s what is needed to make alcohol. Mother nature is awesome. By throwing the right measure of yeast into a vat of sugar water, you provide this fungus with the ingredients it needs to survive. It eats the glucose, farts out carbon dioxide and produces alcohol as a by-product according the following chemical equation:
C6H12O6 –> 2 CO2 + 2C2H5OH
Glucose –> Carbon Dioxide + Alcohol
French microbiologist and chemist Louis Pasteur was the one who discovered that adding yeast to sugar and water yielded alcohol and this lead to the conception of the field of fermentation, which actually has a name: zymology. The same man who brought us pasteurized milk also discovered that the acidity of a sugar solution could affect the speed with which the yeast metabolises sugar. This is an important concern of wine-makers because grapes naturally contain acid and if the solution thrown into the vats at the end of the day is too acidic or too alkaline, the yeast won’t ferment optimally. The result is that it can end up affecting the taste of the wine considerably.
It could mean the difference between pinot and piss.
What’s in a Grape?
Grapes may seem small, oval and innocent, but they’re packed with all sorts of stuff that winemakers take a very great interest in. And rightly so, because even though a good wine may have a bouquet of (smell like) citrus, guava, green peppers, passion fruit, a crisp spring morning and the possibility of a good rodgering, there’s only one fruit that goes into it’s making and that’s grapes, which, as it turns out, contain more than just sugar and water:
- Sugar (glucose and fructose)
- Two main acids: tartaric and malic acid
- Vitamin C
- Vitamin A
- 20 Different amino acids
- Esters (sweet-smelling hydrocarbons)
The exact time of year the grapes are harvested is extremely important, because the older they get, the sweeter they become, very much unlike your cantankerous grandfather. Grapes that are overripe contain a lot of sugar, which is why “late harvest” wines are sweet and taste like raisons. Grapes that aren’t ripe enough don’t contain enough sugar, which you will know if you’ve ever innocently plucked an unripe grape off the vine. They cause your face to implode.
THEN of course there are the different kinds of grapes to consider. Sauvignon blanc, chenin blanc, riesling, sémillon, gewürztraminer, chardonnay, moscato and pinot grigio are all cultivars (kinds) of grapes that are used to make white wines. syrah, cabernet sauvignon, zinfandel, merlot, malbec, barbera, pinot noir and sangiovese are all cultivars of grapes that are used to make red wines.
What determines the taste and colour characteristics of the kinds of wines produced from these cultivars is the size of the grape, the thickness of the skin and the flesh-to-skin ratio of the grape. The skin is the source of all the chemicals that make a wine heavy, full-bodied and dry, so the thicker the skin and the smaller the flesh-to-skin ratio of the grape, the more complex, more full-bodied and drier the wine will be, such as the cabernet wines. Large grapes with thin skins therefore yield wines that are fruitier and light to medium bodied, such as merlot.
SO how do these delectable varieties of grapes get from the vine and into your face after a really crap day in the office?
Wine in the Making
Grapes are plucked off their gnarled vines and delivered to the cellars where all the leaves, stems, rotten grapes and unlucky caterpillars are removed. It is here that the sorting procedures begin that will determine what kind of wine these valiant grapes are destined to become.
White wines are made from the grape juice alone, so these grapes will have their skins removed after crushing. Red wines are made from the juice AND the skin, so they get to keep their clothes on. The grapes are crushed and the resultant sludgy, lumpy grape goo is pumped into shallow fermentation vats. Here, in the case of red wine, this purple porridge is stirred up and constantly agitated to prevent bacteria from establishing a foothold on the floating grape skins like tiny little Rose DeWitt Bukaters on tiny little grape skin doors in the middle of a vast purple Atlantic Ocean.
Just saying… they COULD have made it work
Yeast can be added to aid the fermentation process, during which time the mixture will become increasingly alcoholic and less and less sweet as all that glucose is metabolised by the yeast. The mixture is also stirred up to encourage oxygenation of the mixture, since yeast needs oxygen to live.
By the way, never EVER search the word “yeast” in Google Images. Some things cannot be unseen.
Once fermentation is completed to the desired extent by the winemaker, in other words the right level of alcohol content, sweetness and balance of flavour has been achieved, the sludge will be run through a series of machines that will press out the skins and other flotsam and jetsam so that the remaining mixture is juicy juice. This is then transferred to either wood, usually oak, or steel barrels, depending on the precise taste characteristics the winemaker is trying to achieve.
Wooded or Unwooded?
Whoops! How did I get in that picture?
Wine that is matured in wooden barrels tends to have a – SURPRISE – woody flavour. It gives it an aged, earthy characteristic that is most pleasant in a headier chardonnay or shiraz. And, of course, the age of the wood itself can influence the outcome of the wine. Flavours can also be added to maturing wine by introducing planks of wood that have been toasted over a fire. This tends to result in the rich, coffee, chocolatey flavours that have become so immensely popular here in South Africa.
Throughout maturation, the winemaker will regularly sample the wine to ensure that it is on the right track to securing him a beautiful, expensive white or a quaffable supermarket red, or vice versa. Finally, after a maturation period of six months to three years, the wine will be carefully filtered, bottled, sent to market, purchased by people like me and poured down our gullets, ending the grand process in our brains where it is allowed to affect our judgements.
Class Dismissed: Your Take-Home Message
Winemaking may sound like one of those professions you’d be LUCKY to have, like professional surfing or being a judge on Masterchef, but there is a huge amount of pressure involved. It takes an intimate knowledge of organic chemistry and a fine palate to achieve wines that people (notably obnoxiously wealthy people) consider worthy of their Coq au vin or Bœuf bourguignon. What’s more, you only have one harvest every year to get it right, so unless you are a trust fund baby with unlimited cash at your disposal, you simply cannot afford to bugger around.
Think about this the next time you sip on a smooth merlot, an aged syrah or oaked chardonnay. And think about all the billions of fungi that had to die to deliver to you a succulent sauvignon blanc or a tenacious tempranillo. Appreciate the chemistry and toil that goes into the libation you so enjoy after a day of work, or a day of anything really. Now go forth and drink wine!
If it was good for Jesus, it’s good for you!
Image Source: The Independent “Vatican City drinks more wine per person than anywhere else in the world.”