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04. How grapes get into a glass

In the Côte d’Or it all starts with the “ban de vendanges”…

Actually that was until 2006 and was the legal starting date of the harvest, specific to each appellation. Without special permission it’s wasn’t allowed to harvest before this date; the ban de vendanges is simply, if you like, a mechanism to aid quality by trying to minimise the picking of under-ripe grapes.

Once the date has been announced, each domaine organises its own harvest based on the condition of the grapes in each of their vineyards – in some cases this can be 2 or 3 weeks later. The criteria for maturity of the Pinot Noir grape differs from that of the Chardonnay. With Pinot Noir, one speaks of “phenolic maturity” which takes into consideration the level of maturity of the anthocyanins and the tannins of the grape, and more specifically these elements found in the skin. The finished wine will be more or less red (anthocyanins) and tannic (tannins) based on the quality and quantity of these two elements – both are vintage dependent factors. As with the Chardonnay grape, the proportion of machine-picked grapes increases yearly, essentially for economic reasons (two to three times less expensive than hand picking), but also to give logistical flexibility. Nonetheless all domaines concerned with quality continue to hand pick. For some estates manual picking is essential as this enables whole cluster maceration for red grapes. When a manual harvest is done, the grapes are taken to the “cuverie” (the winery) in plastic perforated cases or in large bins. Not everyone has a sorting table, but where used, they allow the grapes to drain if they have been picked in the rain, and they facilitate the removal of rotten or damaged grapes which could compromise the quality of the wine. Some estates prefer to do this sorting in the vineyard while picking rather than risk over-handling and oxidising the grapes on a sorting table.

Grape stems are rich in lignified elements (wood). If the grapes are not perfectly ripe, the stems might bring undesirable (herbaceous) flavours to the wine. On the other hand, retaining the stems for the vinification of red grapes can be positive by contributing more tannin – indispensable for the structure of the wine and for stabilising its colour. Destemming consists of separating and eliminating the stems from the berries and is a common practice in modern winemaking. Destemming can be total or partial. Some estates prefer not to destem at all. The destemmed grapes or entire clusters might also be crushed, then placed directly into a fermentation vat or tank. The traditional oak fermentation vat is being successively replaced by stainless steel tanks or large concrete vats. Generally these vats are open at the top. At this stage the little bit of juice which was extracted by crushing the grapes is still white. As with all red French grape varietals, the juice of the freshly crushed Pinot Noir grape has no colour. It is only during the maceration with the skins that the juice takes on its colour.

The grapes stay in tank for two to three weeks. This is where the colour and tannins from the skins, pips and stems concentrate in the juice and the alcoholic fermentation takes place. With the introduction of thermo-regulated stainless steel tanks, more and more estates do a cold maceration (12-18° C) for two to four days just after the must (the mix of liquid and solid grape material) is placed in the tank and before the alcoholic fermentation. The extraction of colour is enhanced by this step. Reducing the temperature is also possible in wooden and concrete tanks by placing cooling coils within the tanks. Other methods of extraction based on contact of the skin and juice are pigeages and pumping over, which are done 1-3 times a day – depends on the winery. Pigeages consists of breaking up the cap (or chapeau) made up of the grape solids, and submerging it down into the tank. During the fermentation the cap is brought to the surface by tiny bubbles of carbon dioxide. At most small estates pigeage is still done by workers physically “descending” into the vat with bare feet. These days pigeage is more commonly done with the aid of a “pigeou” (a large disc with a long broom-like handle) that is pushed by hand down into the tank. Some estates, notably those with large production, have entirely automated this step with automatic pigeurs or with tanks that are auto-pigeantes. Pumping over, which is less frequent in Burgundy than in Bordeaux, consists of pumping juice from the base of the tank over the top, thus moistening the cap. The degree of extraction is greater when this step is carried out so that the juice comes into contact with air. In fact, tannins and anthocyanins fix more effectively in the presence of oxygen. The alcoholic fermentation begins in the favourable conditions created by pumping over and pigeages (with or without the addition of a yeast culture, at the discretion of the winemaker). It is important to watch the temperature of the cap to be sure that it does not exceed 35°C during the fermentation. As the concentration of alcohol increases this further aids the extraction of the phenolic components, the anthocyanins and tannins.

After two to three weeks in tank and at the end of the alcoholic fermentation, the new wine is taken out of tank. First, the free run juice is drained, then a plastic pitch-fork is used to empty the tank of the remaining skins, stems, seeds and juice. The cap (or marc) is then pressed. This pressed wine is always higher in colour and tannin than the free run juice – so much so that it is not always incorporated in the final blend or assemblage. Note that in contrast with the vinification of white wine where the white grapes are pressed immediately, the pressing of red grapes for the production of red wine takes place after the must has undergone maceration and alcoholic fermentation.

The pressed wine and the free run wine can be assembled in tank or can be aged separately in cask to be assembled before bottling. In either case, the wine is aged in barrel in a wine cellar maintained at less than 16°C. Some estates choose to stir the fine lees (solid grape material transferred in the wine) up into suspension in the barrel for a richer wine (batonnages), but this practice remains uncommon for red wine. The malolactic fermentation generally takes place in cask, often within six months of the alcoholic fermentation. Today some winemakers prefer that the malolactic fermentation take place more rapidly and more directly after the alcoholic fermentation.

During the barrel aging period, wines are racked (in the presence of air) off of the lees after the malolactic fermentation, which softens the tannins in the wine. Generally red wine is aged in barrel for a longer period than white wine. The percentage of new oak used for the barrel aging period varies depending on the appellation and the choice of the estate. Great wines are generally aged in a higher percentage of new oak as they have more depth and body and will not be overpowered by the oak. In addition to the flavours and tannins that new oak barrels contribute to a wine, they also allow a slow oxygenation which encourages the wines’ evolution. A handful of winemakers go so far as to use 200% new oak i.e. 100% during the first year of barrel aging, then after racking the wines are put into another 100% of new oak barrels for a second year.

In contrast to white wine which is rich in protein, red wine contains large amounts of tannins and anthocyanins (colour pigments) which are susceptible to precipitation in bottle. The addition of egg whites (albumin) to red wine during barrel aging eliminates some of these phenol components – this process is called fining. As a result, the wine becomes more supple and limpid, but may not retain all it’s flavour components. After the wine has been in the presence of a fining agent for approximately a month, it is racked and can be filtered just before bottling. As with white wine, filtration is not done systematically, in fact many great domaines no longer filter unless absolutely necessary. This technique is still highly respected though, as it guarantees the microbiological stability of the wine by eliminating the yeast and bacteria populations. Among the different types of filters available are depth filters which remove yeast, bacteria, tartrate crystals and other materials from the wine (differing grades of filter pads available), and membrane filters which sterilize wines at bottling. The most popular are diatomaceous earth (kieselguhr), plate and frame filters, membrane filters and even tangential filtration which is a type of membrane filtration.

The final step at the domaine is bottling into 750 ml, 375 ml, and 1500 ml bottles. Few domaines are large enough to warrant owning their own bottling line, hence, this is outsourced to mobile bottling units. Particular precaution is given to protecting the wine from oxidation during bottling necessitating the addition of a small dose of sulfur. Bottles are corked and stored in the domaine cellar until just prior to shipping, when they are cleaned, labeled and packed.

Technical notes…

Phenolics and Pinot Noir. Pinot Noir has a very low phenolic content relative to other red grapes. These phenolics develop in the grapes, pips, skins and stems by the effect of UV light, hence, phenolic maturity is as much related to the availability of sunlight as temperature during the growing season. The phenolic (substituted hydrocarbon rings) compounds are principally:

Anthocyanins: RM Willstätter received the Nobel prize for chemistry in 1915 for his work on plant pigments. He discovered that fruit and flowers that have red, blue or purple colours contain pigment molecules based on cyanidin (right). When sugars attach to the points on the molecule (marked in red) the molecule is now called an anthocyanin. Higher sugar contents increase the solubility and stability of anthocyanins in water. Anthocyanins are divided into five classes depending on their structure: cyanins, delphinins, malvins, peonins and petunins – did you spot the name of your favourite flower?, this is where their colour comes from – the proportions of each will depend on the grape variety. Interestingly if the anthocyanin has mainly hydroxyl (-OH) substituents at the points marked in blue, the colour is shifted towards blue, whereas if the substituents are methylated (-OCH3) the colour is more red. Malvin is the most red of these compounds and is therefore responsible for most of the red colour in a young wine. The anthocyanins complex with sugars in the wine which helps to ‘fix’ the colour, it is only with aging that the anthocyanin complexes start to disassociate and start to join up with tannins to form polymers – this causes a gradual reduction in the intensity of the colour.

Tannins: literally a range of compounds with the ability to tan leather (precipitate proteins!) they are a complex group of phenolic (aromatic) compounds which can be split into two groups; the ‘simple’ structures of non-flavanoids which can have their origin in either the grape material, yeast or oak, and the more ‘complex’ flavanoids which come only from grapes/stems. The anthocyanins from above are classed as flavanoids. In addition to helping to fix the colour with the anthocyanins, the tannins provide the characteristic dry, astringent mouthfeel in red wines and also act as antioxidants.

Malolactic Fermentation After the alcoholic fermentation the wine has a mixture of volatile (mainly acetic) acids and non-volatile acids, mainly tartaric and malic acids. Malolactic fermentation is the action of bacteria and yeast strains on the malic acid, converting it to lactic acid. Because malic acid has two acid groups and lactic acid has only one, the malolactic fermentation results in a lowering of acidity (higher pH) – the acid group is lost as carbon dioxide. It is generally accepted that for ‘high-quality’ wines the ‘malo’ (as this fermentation is often called) is a good thing as it replaces the sometimes ‘rough’ malic acid with the smoother lactic, and produces a further layer of complexity. It is typically responsible for the buttery taste in chardonnay wines.

My sincere thanks to Becky Wasserman-Hone for the text upon which this page was based.

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