September 2007

Dear Friends of Monolithos,

This month, we take a closer look into the grape berry anatomy and attempt to explain briefly how its constituents influence wine quality.

The small fruit of the vine is the fundamental element from which the amazing adventure of wine making begins – small, coloured berries producing the juice which originates endless styles of wine. There is no sure and reliable evidence about how “wine” was discovered, in particular, how a small berry, rich in sweet juice, could materialise into a beverage very different from the original matter.

The grape is the fruit of the vine, and it develops in bunches as a consequence of the fecundation of flowers. The grape berry is fixed to the stem, and this part is rich in water and minerals. It also contains tannin that can impart to the wine a certain pungency (stem taste) and a grassy tang that can negatively affect the taste of wine. This is why, based on the variety of grapes and the type of wine made, the berries are de-stemmed.

From a winemaking perspective, the grape berry has three major types of tissue – flesh, skin, and seed. These tissues vary considerably in composition, and therefore by extension, they contribute differently to the overall wine composition. The bulk of wine is derived from the flesh of the grape. Because of this, the composition of wine can be manipulated by simply changing berry size. As a general rule, wines made from smaller berries will have a higher proportion of skin and seed derived compounds.

The grape berry's appearance is usually round or stretched. It is covered by the skin whose thickness varies according to the grape variety, and represents 5% to 12% of a mature grape’s weight. The skin of the grape, which is covered by a waxy-like substance, is rich in pectin, cellulose, aromatic substances and polyphenolic components. These are commonly known as tannins, and are responsible for the colour in red wines, as well as for the structure and astringency. Both aromatic substances and polyphenols contained in the skin can be extracted by means of maceration (the procedure of leaving the grape skins and pips in contact with the juice). The quantity of extraction is proportional to the time of maceration.

Grape juice, both of the white and the red berried species, has a greenish yellow colour, therefore when the maceration of the skin in the must is completely avoided, it is possible to obtain white wines from red grapes. The skins of red berried grapes are macerated in the must with the explicit purpose of giving colour to red wines and to extract aromas and tannins. Likewise, a short maceration of the skins – usually a few hours – can be used for the production of rose wines with red berried grapes. It should, however, be noted that the quantity of colorant substances contained in the skin of red berries grapes depends to a great extenton the grape variety and, therefore, every red grape will have different colorant capacities and qualities.

Another component of the grape is the pulp or flesh. This makes up 80% of the weight of a bunch of grapes and is, therefore, the most important part. It is colourless and is composed of water, sugar (glucose + fructose), three main acids (tartaric, malic, and citric), pectin, several mineral elements and especially potassium and nitrogenous substances which constitute the main source of food for yeast. It also contains enzymes and vitamins. The area which is just under the skin is rich in tannins and aromatic substances, sugar and acids. The middle part has the highest concentration of sugar and acids.

In the inner part are the pips which are rich in polyphenols and are of a very astringent nature. These will be extracted during the pressing of berries. There can be two, three or four pips or seeds per berry, which constitute 4%-5% of the bunch weight. Seeds are of relatively minor importance in winemaking, although if they are crushed, the bitter tannins they contain are released.

In white winemaking, the contact time between juices and seeds is short (a few hours) and the effect of tannins from seeds is minimal. However in red winemaking, the prolonged contact during maceration and fermentation means those tannins are very likely to be dissolved in the finished wine.

By pressing the berries, we obtain the must which is made from the above-mentioned liquid and solid substances. Water is the fundamental element and represents about 70%-80% of the must. Sugar constitutes 15%-30%, whilst acids form 0.5%-1.5% and, as already explained, there are other substances such as minerals, vitamins, polyphenols, aromatic components, pectin, nitrogenous substances, enzymes and micro-organisms (yeasts, bacteria and moulds).

The grape berry is essentially an independent biochemical factory. Beyond the primary metabolites essential for plant survival (water, sugar, amino acids, minerals, and micronutrients), the berry has the ability to synthesize all other berry components (for example, flavour and aroma compounds) that define a particular wine. The grape is a fruit, with an unusually complex balance of delicate ingredients. It appears unique in its ability to mimic the smells and flavours of other fruits, depending on how and where it is grown. In warm climates, a versatile white grape variety can evoke smells of pineapple, mango and other exotic aromas. In the much cooler regions, the same variety could smell steely and austere, rather like wet stones, with flavours ranging from citrus to apple.

The essence of wine lies predominantly in its colour, aroma and flavour. It is the seemingly endless diversity of these attributes that keeps the consumer fascinated by wine. Wine would not be as popular as it is today without this wide range of fruit aromas and flavours. Wine is also rich in minerals and proteins. Minerals such as potassium and calcium are picked up from the soil by the vine roots and interact with the acids to influence the taste of the finished wine. Proteins are derived from the grape pulp, and can cause problems by making the wine cloudy if they are not treated appropriately.

Winemakers are therefore continually seeking new – and rediscovering old – techniques to enhance grape character and to positively influence the sensorial diverse qualities of wine. An understanding of berry anatomy, when and where berry components are produced, is the first step in understanding the rationale behind managing wine style in the vineyard. Many advances have been made in understanding how the grape berry develops and the components that are important in wine. During the last few decades, the quality of wines has undoubtedly improved as a direct result of being able to manipulate the grape berry through production practices.

Wine News and Information

In what scientists are hailing as the greatest breakthrough in a generation, Australian researchers have identified the aromatic compound that produces the black pepper smell in red wine. Boffins at the Australian Research Institute spent eight years trying to find the compound, dubbed Rotundone, which was discovered last year, but kept secret while patents were secured. The black pepper aroma is typical of many top-end Australian Shiraz wines. The discovery could revolutionise winemaking, enabling winemakers and winegrowers to alter the way they produce their wine in order to minimise or maximise certain flavour characteristics.

“Once you know what the compound is, you can find out what, in the vineyard or winemaking process, creates it, and therefore maximise it,” said Jamie Goode, author of The Science of Wine and wineanorak.com. “It might help make better, cheap wine,” he said. Top Australian winemaker Bruce Tyrell agreed, telling an Australian newspaper that the discovery would help the “more commercial end” of the wine industry, but that at the top end, he was more “inclined to take what nature has given me”.

Italy's first official 2007 harvest preview, published by Unione Italiana Vini, predicted that this year's vintage will be the earliest harvest in the last 30 years. The report says picking will begin an average of 15 days earlier, with a possible 5% decrease in yields, stressing that climate conditions during the next few weeks will be of vital importance to both aspects. In what mirrors harvest conditions throughout much of northern Europe, weather patterns have brought the usual growing cycle forward by around three weeks.

However, not all producers and regions are expecting an early harvest. For southern Italy, it is estimated that harvest conditions are more or less on track, as weather conditions throughout the year have been less extreme.

Monolithos Monthly News

In August, we began testing the fruit for physiological ripeness and flavour before we decided which vineyard was ready for harvest. Sugar readings were taken from each block on a regular basis. We checked the colour of grape seeds to see if they had developed a brownish hue (a sign of truly ripe grapes).

Once the harvesting decision has been taken for a particular location, the grapes are hand-picked in the early morning hours before the sun has had a chance to warm the vineyard. The clusters are placed into small picking buckets, which are then loaded into a small truck. The cool fruit is then transported to the winery for processing. Traditionally, “Neropies” vineyard, planted with “malvasia”, is the first site to be harvested and this year’s crop was collected during the third week of August. In September, we plan the harvesting of “pygadhia”, followed by “ayiasmata” locations.

We thank you for your continued support, take care and remember that,

“Appreciating wine requires knowledge which comes largely from wine-tasting experiences.”