Obviously, some wines taste better than others. We all have experienced it. We open a bottle of wine and try it for the first time, only to realize it is subpar, or on the contrary, a good surprise.
We all have our personal preferences of course, white, red, rosé, sparkling, sweet or dry, light or powerful, which style do you prefer? It is subjective and there is no point arguing with that.
Thus said, what are the objective facts that we can rely on to find a great bottle of wine?
Let’s have a closer look at the winegrowing and winemaking stages, how to grow grapes and turn grapes into wine, to get a better understanding of the whole process, from the vine to the glass.
Wine is made with grapes and grapes are growing on vines, so if we are looking for a good bottle of wine, the first place we should examine is the vineyard.
“Wine is sunshine held together by water” – Galileo Galilei (1564-1642).
Plants have the fantastic ability to capture carbon dioxide from the air, absorb water underground, and use solar energy to produce carbohydrates and release oxygen through photosynthesis. Basically plants are harvesting sunlight and supply a good fraction of the air that we breath, while we harvest plants to eat and get some energy. When we are drinking wine we are actually drinking sunlight. Beautiful thought, isn’t it?
- Topography: A good location, with at least 1500 hundred hours of sun during the growing season, from March to October in the northern hemisphere, with south facing slopes to get maximum hours of sunshine and achieve a good ripeness, or facing north to keep some freshness and acidity (it’s just the opposite in the southern hemisphere). Hilltops are exposed to harsh weather and the bottom of the valleys are easily flooded so generally mid-slopes are preferred. All the Premier Cru and Grand Cru vineyards in Burgundy are located on the mid-slopes, whereas the villages and regional appellations are located slightly or further above and below, and big brands source grapes from multiple origins to blend together.
- Meteorology: A cool climate will translate into less sugar and more acidity, perfect to produce sparkling wine, lively white and light bodied red. On the contrary, a warm climate, will give us grapes with more sugars and less acidity, hence wine with more alcohol, more roundness, maybe too heavy for sparkling and white, but suitable for rosés and perfect to make full bodied red and fortified wines. North of France, Champagne, Alsace, Chablis are producing mostly white wines; Loire Valley and Burgundy in the middle of the country have a good mix of white and red; and the warmer wine regions of Bordeaux, South West, Languedoc-Roussillon, Rhone Valley and Provence are famous for red and rosé wines.
- Geology: There are many different types of rocks (eruptive, sedimentary and metamorphic), as well as their minerals constituents (silicates, carbonates, sulfates…) and chemical elements (oxygen, silicon, aluminum, iron, magnesium, calcium, sodium, potassium…), it is complicated to say the least, requires years of study to fully understand and probably deserve an article by itself.
A common observation gathered from vintners experience around the world is that lighter soil like sand, silt and alluvial, seem to give lighter wines, more feminine, like a dancer, whereas heavier soil like clay, gravel and pebbles, seem to produce heavier style of wine, more masculine, like a boxer. An over-simplification but it is easy to remember.
The actual quantity of minerals found in grapes is small (2-3g per kilogram), the quantity of minerals left in wine is even smaller (200-300mg per litre) and the perception of minerality in the mouth is subject to the wine drinker interpretation, with too many variables to quantify and wide varying sensitivities after all.
- Botany: there are 79 species of grapevines in the genus “Vitis” and between 5 000 to 10 000 varieties of “Vitis Vinifera” in the wild, but all commercial wine is made from a few varieties of Vitis Vinifera (Chardonnay, Sauvignon Blanc, Merlot, Pinot Noir…). Since the Phylloxera crisis that plagued Europe in the 1870s (a kind of louse that attacks the vine roots , eventually killing the vines), American rootstock (usually Vitis Aestivalis, Rupestris, Riparia or Berlandieri…) is planted in most part of France as it is immune to the disease and a scion of Vitis Vinifera is grafted on top of it.
A few vineyards with sandy soil in the Loire Valley and the Pyrenees, as well as most vineyards in Chile and Australia, still have Vitis Vinifera vines planted “franc-de-pied” directly in the soil. Ungrafted vines are said to produce wine with greater harmony and complexity. The grafted vines can be all identical clones from the same mothervine or a selection of different plants from a great vineyard ("selection massale"), which maintains more gene variety. The choice of the rootstock and the graft, and their adequacy to a specific wine region, soil and climate, is like a marriage, it can be successful or fail miserably and it takes time and money to find out.
- Old vines: When looking for a great bottle of wine, the age of the vine often comes up in the conversation. Most vines, like people, live about 100 years maximum. The first 25 years, vines are young and vigorous, like children, they have a lot of energy but lack focus, they produce a lot of juice but no concentration. From 25 to 50 years old, vines are mature and yield both quantity and quality, and over 50 years, the vines are considered old, they will yield less and less grapes, until the point where it is not economically viable to keep them. Winegrowers are replacing dying vines bit by bit so that the quality remains more or less the same every year. They usually keep a small plot of old vines to produce the top of their range (“vieilles vignes” in French). In good condition, the roots go deep underground and the wine also has more depth and character.
- Yield per hectare: a determining factor in term of quality, if we have a plot of land of 1 hectare (100m x 100m), and we decide to grow 20 tons, 10 tons, 5 tons or less of grapes, the quality will vary tremendously. Lower yield (< 50hl/ha) usually means more concentration, more colour, more flavour, and more expensive wines. High yield (> 60hl/ha) is better to either produce light, sparkling wine, or cheap bulk wine.
- Farming Methods: there is a large body of evidence that organic and biodynamic farming are better for the environment, the people living on and around the farms, and the consumers. The key to produce high quality crops is biodiversity, not agrochemicals. About 5% of the vineyards are certified organic, aligned with permaculture, agro-forestry and agro-ecology principles, they use cover crops as green fertilizers, copper and sulfur to treat diseases like mildew and oidium, no till, they are planting more trees and hedges, they build walls, ponds and shelters for all sort of birds, bats, reptiles, rodents and small mammals to move around freely. There is a lot more biomass and life underground (insects, earthworms, bacteria, fungi, protozoa) which build up organic matter and provide more oligo-elements and micro-nutrients to the vines, keep them healthy and increase the nutritional value and aromatic compounds found in the crops.
Unfortunately 95% of the vineyards in the world today are conventional, a polite term for industrial, they rely on synthetic pesticides, fungicides, weedkillers, and chemical fertilizers. The vineyards are usually very neat and tidy, there is not much life going on in the vineyards, spreading over tens of hectares, uninterrupted. The soil is more compact, less porous and promote bad anaerobic bacteria. It is also subject to erosion. Plants and grapes contain agrochemicals residues. The air, the soil and the rivers nearby are polluted. In some places, 300 times over the limit allowed for tap water. They also depend heavily on mechanized tools and fossil fuel. This model of industrialized monoculture clearly failed and need to change. There is no future for agriculture if it is not sustainable.
- Microbiology, there are several million microbes per gram of fertile soil and literally tons of biomass beneath our feet. Major microbial groups in soil are bacteria, fungi, algae and protozoa. At the base of the trophic levels lies the soil microbial population which degrades plant, animal and microbial bodies, and also serves as the food source for some of the levels above it. For example, soil protozoa consume enormous numbers of bacteria and even some fungal spores. These in turn are consumed by still larger soil animals (nematodes, mites, etc.) which in turn are eaten by still larger animals (e.g. worms and insects). Thus, nutrients flow through this microbial food web which lies at the heart of controlling soil fertility and plant productivity in the absence of external inputs such as fertilizers. In fact, the role of soil microbes in degrading organic materials and thereby regenerating a supply of carbon dioxide for plants is perhaps their most vital global function.
- Soil pH typically ranges from 4 to 8.5, while pH 7 is considered neutral. Like the temperature of the human body, soil pH affects the quantity, activity, and types of microorganisms in soils which in turn influence decomposition of crop residues, manures, and other organics. It also affects the solubility, or plant availability, of essential nutrients. Phosphorus, for example, is most available in slightly acid to slightly alkaline soils, while all essential micronutrients, except molybdenum, become more available with decreasing pH. Aluminum, manganese, and even iron can become sufficiently soluble at pH < 5.5 to become toxic to plants. Bacteria which are important mediators of numerous nutrient transformation mechanisms in soils generally tend to be most active in slightly acid to alkaline conditions.
- Harvest date: finally, all the work in the vineyard is done, we chose the best location, grafted and planted 5k to 10k vines per hectare, we waited 3-5 years to get decent grape quality, pruned the wood during winter, tied up the shoots in spring, trimmed the leaves in summer, now we need to decide when to pick the grapes, all our effort this year will be judged on the quality of the harvest that day. Too soon, the tannins will be green and we risk to have sappy flavours extracted from the stems and seeds, too late and there won’t be enough acidity to ensure freshness, microbial stability, and potential for aging.
- Manual harvests are costly and labour intensive, but allow winegrowers to pick only the grapes at optimum ripeness, if the bunches are unripe, we can leave it there and come back in a week or so, if it is rotten, just cut it and it will fertilize the ground. Winegrowers will need to carry baskets of 25 kg, sometimes on very steep slopes.
- Mechanical harvests are fast and cost effective but all the grapes will be mixed together (ripe, unripe, rotten) and will need to be sorted out later, or maybe not, for bulk wine production. The machines are also very heavy and compact the soil, reducing further the soil life activity, and result in what we call “green concrete”. The grapes are also lightly crushed during mechanical harvests, leaking juice on the conveyor belts that start to oxidise in the truck tank, so winemakers have to add more sulphites in commercial wines.
After the harvest, the grapes are swiftly brought back to the winery, sorted, and go through direct pressing for white wine (and rosé de Provence), to gently extract the clear juice from the solid matter (skins, stems and seeds), while the leftover pomace is usually sold to distilleries.
For red wine, the grapes are destemmed (partially, or not), crushed, and the juice is left to macerate on the skin to extract colour and flavour as desired (from a few hours for “rosé de saignée”, 1 or 2 weeks for light bodied red, up to 2-3 weeks for the deepest red wines), before being pressed. The free run juice and press wine can be blended together or vinified separately.
The young wines will then continue their alcoholic fermentation (yeasts converts sugars into ethanol and carbon dioxide), and for most of the reds and a few white wines, a malo-lactic fermentation (the wine bacteria “Oenococcus Oeni” converts crisp malic acid to soft lactic acid), and slowly mature into wine in oak barrels, cement tanks or stainless steel, being racked off the lees multiple times, clarified with fining agents and/or filtered before the final blending and bottling operations.
Most people believe that wine is only fermented grape juice, but as a complex chemical mixture dependent on the activity of microorganisms, wine can be unstable and reactive to changes in its environment. Depending on the appellation rules and the winery philosophy, there are over 100 different kind of additives and manipulations authorized in modern winemaking. Let’s have a look at the most common practices:
- Yeasts are microorganisms that turns sugars into alcohol and carbon dioxide. There are many different genera (Kloeckera, Candida, Brettanomyces…) but the most efficient is saccharomyces cerevisiae (the real winemakers). Different kinds of yeast greatly affect the flavours of the resulting wine. Traditional winemakers prefer indigenous yeasts that are present on the skin of the grapes in the vineyards and on their winery equipment, as an element of terroir, while modern winemakers used a cocktail of cultured yeasts, engineered to thrive in specific pH or alcohol content, and taste like strawberry, blackcurrant, apple, banana, etc.
- Chaptalization, named after French chemist JAC Chaptal, winemakers add sugar (beetroot or sugarcane) to the grape must (12 to 24 g/L) prior to alcoholic fermentation to boost the potential alcohol content (+1% to 3% ABV). Often used in cool climates, when poor weather conditions or excessively high yields didn’t allow the grapes to ripe fully, but it is becoming increasingly rare, thanks to global warming. Chaptalized wine often seems unbalanced, too alcoholic and burning in the mouth, while other compounds, like fruity aromas, tannins and acidity are less prominent.
- Rehydration, in warmer regions where over-ripening is a concern, the opposite process of dilution with water is used when the grape must has too much sugar for normal fermentation (> 15% ABV), water may be added to some extent to lower the concentration and keep the wine palatable. Increasingly common South of France due to global warming.
- Acidification, similarly to rehydration, in warm climates and warm vintages, tartaric acid is often added to the grape must to compensate for excessively high levels of sugar and low levels of acids. Acidity is one of the key element of a wine structure, as it brings freshness, drinkability and microbial stability. Wine acidity normally varies between 3 and 4 pH (Vinegar is 2, Coca Cola is 3).
- Reverse osmosis, the tiny particles of water and alcohol pass across the membrane more readily than the other solid components, leaving a "wine concentrate". Then, the water and alcohol mixture is distilled to separate the alcohol from the water. The wine concentrate is then diluted with both elements to reach the desired intensity. It can be used either in cool climates, to remove some water from the unfermented grape juice, thereby increasing its sugar concentration, or in warm climates to remove excessive alcohol (and to pay less tax, incidentally, in some countries). Now, let's think about the difference between freshly squeezed orange juice and concentrated juice mixed with water... are they really the same?
- Thermovinification is an alternative to the traditional maceration processes for extracting dye compounds present in the skins of red grapes. Advantages include the reduction in the microbial load of fruit, inhibition of undesirable enzymes, extraction of anthocyanins and other polyphenols and reduced time for winemaking. It also reduces positive flavours and change the profile of the wine (fresh pineapple -> canned pineapple).
- Flash Pasteurization, named after French scientist Louis Pasteur, pasteurization in winemaking is a process that eliminates acetic and lactic bacteria, as well as other yeasts which can cause faults aromas in the wine, bringing the wine to approximately 72°C in a very short time (20 to 30 seconds), then cooling it just as quickly. When the quality of the harvest is not great, it is possible to reduce the amount of sulphites required to stabilize the wine. If we compare pasteurized and unpasteurized cheese or wine, anyone can taste the difference I think?
- Fining agents, traditionally 1 or 2 egg white per barrel but also casein (milk protein), isinglass (fish collagen), bentonite (very fine clay made of aluminium-silicate from volcanic ash), gelatine, activated carbon and PVPP (Poly-Vinyl-Poly-Pyrrolidone, a synthetic polymer), to attract floating particles and clarify the wine, to reduce the level of phenolic compounds associated with bitterness and soften the wine, or to remove off-flavours and unwanted colours.
- Filtration is often done after fermentation to remove potentially active yeast and lactic acid bacteria. Depth filtration works by passing the wine through a thick layer pads of cellulose fibres, diatomaceous earth or perlite. In surface filtration, the wine is run parallel to a thin membrane filter, known as cross-flow filtration, to minimize the filter clogging. The finest surface filtration, microfiltration (<0.45µm), can sterilize the wine and so is often done immediately prior to bottling. The only thing left is water, alcohol and a bit of colour, flavour.
- Cold stabilization, tartaric acid is most common in wine as potassium tartrates and on exposure to low temperature (inside the fridge) they may crystallize out unpredictably. The crystals, though harmless, may be reckoned unattractive by some consumers. To prevent this the wine may undergo "cold stabilization", in which it is cooled to near its freezing point to provoke crystallization before bottling.
- Sulfites, the scapegoat for all the wine industry wrongdoings, there are 2 origins, chemical SO2, which comes from the petroleum industry, basically oil refined with sulfuric acid through mechanical processes. If it is in the form of salts, it is called sulphite, bisulphite or meta bisulphite. And the sulfur from volcano, a native element that is purified, contains no trace of tar, nor trace of arsenic. Used since the Roman Antiquity, its role is not to destroy the yeast, but to divert their activities. If it is used in small doses, it combines very little with other elements, leaving a significant active part free in the wine and only improves the youthful quality of the wine. It has no wrongdoing on the human being.
3) In the Glass
Good grapes make good wines and the best wine-makers unanimously prone minimum intervention, aiming to produce wines that truly express the characteristics of the grape varieties and terroirs of origins in the vintage, without oenological additives or technological processes that would erase a sense of place.
What makes wine so interesting, and a bit intimidating at first, is the diversity and typicity of the wine regions and grapes varieties. They all have a unique personality and different characteristics. Wine can be delicious and memorable if it is well made, or dull and boring if it is standardized.
If you are a winemaker and make 5 000 bottles, 50 000 bottles or 5 million bottles, you won’t be using the same ingredients and the same processes. Same thing for beer, cider, bread, cheese, pizza, burger, orange juice, tea, coffee, etc... Fast food and fine dining, artisanal and industrial, quality and quantity, often go in different directions.
Needless to say that most of our wine-makers are following organic farming principles, use indigenous yeast fermentation, nor fining, nor filtration, and make wine in very small batches. They are not found in supermarkets and duty free shops all around the world, we import them directly from the producers in France and guarantee the best price in Singapore, hope you will give them a try and enjoy the difference!