Noble rot: locut. Noble rot is a fungus, Botrytis cinerea which develops on grape berries under certain conditions of humidity and sunlight, allowing the production of wines from overripe grapes, acting as a natural concentrating agent.
This fungus can, under other climatic conditions, be called gray rot, thus damaging the crop.
Un champignon microscopique : Ainsi, l’élaboration des grands liquoreux (Sauternes, Monbazillac, Layon, Barsac mais aussi Tokaji hongrois ou Trockenberenauslese allemands, etc.) repose-t-elle sur un acteur indispensable, le Botrytis cinerea, champignon microscopique responsable de la célèbre pourriture noble. Pourriture n’est peut-être pas le bon terme, flétrissure serait sans doute un against mieux adapté pour décrire le phénomène occasionné par ce champignon qui se nourrit de l’eau contenue à l’intérieur du raisin avec pour effet de concentrer sucres et acides naturels en même temps que le taux de glycérol. Les baies prennent alors un aspect ridé, ratatiné. Elles sont violacées, desséchées comme un raisin de Corinthe et couvertes d’un duvet blanchâtre tel de la cendre. D’ailleurs, Botrytis cinerea ne signifie-t-il pas grappe cendreuse. On parle alors de grains botrytisés, de grains rôtis et confits.
The same cluster may present all stages of development of the fungus: ripe berries, full rotten stage and roasted rotten stage. It is therefore a more complex and above all more precarious process than simple late harvests from grapes which have simply matured longer than usual.
This excess maturity which increases the degree of alcohol up to 16°, even 17°, and at the same time the concentration of residual sugar, substances and aroma, can only be achieved by juggling chance. . If we wait too long, we risk disastrous rain or frost. Are the grains sufficiently candied, sufficiently wrinkled? Do they have this grayish color which will decide the winegrower to start the harvest?
Performance : And what harvests since they are done by successive sorting. You have to go back and forth up to five or six times through the ranks (from September and a few times until Christmas) because as we have seen, noble rot never affects the entire bunch. Each sort carried out will give a different wine. The yield is obviously very limited. It produces an average of 25 hl/ha, the equivalent of 3 bottles.
Development : The Botrytis cinerea fungus is present as soon as the vine flowers, on the berries. Its development must be respected and controlled from June to August, so as not to prematurely jeopardize the ripening of the grapes. Some wine growers therefore abhor any spraying of anti-fungal products. Only green work (disbudding, leaf stripping, etc.) makes it possible to control its too early development, which is only desired when the berries have reached sufficient maturity.
The fungus feeds on the water of the grapes and has the effect of concentrating the sugar inside the berries. It also has consequences on the aromas of the wine (typical nose “ botrytized "). A “Botrytis sweet wine” is not a “sweet dry wine”: noble rot sugars are the most complete, they are of great purity in the mouth.
The development of noble rot depends on many factors, including two main ones:
1/ water supply conditions for the vines to avoid bursting of the grain skin. Deeply rooted vines are therefore required.
2/ for a good proliferation of this fungus, it is essential to start from healthy and fully ripe grapes. The nights must then be cool, the dew abundant and the morning fogs (dissipated two or three hours after sunrise) due to the presence of watercourses extend over the vineyard.
So, it is this alternation of dry and humid periods which will allow the development of this microscopic rot:
– morning fogs to stimulate fungal development;
– hot, sunny afternoons to facilitate the evaporation of water through the film which has become permeable.
Obviously, nothing should disturb this beautiful arrangement (rain in particular) which can lead to another type of rot, the one feared by winegrowers, gray rot.
This noble rot will thus give the grapes complex aromas of honey, candied apricot, sweet spices, black tea, white pepper, saffron, burnt notes, complex acidic and sweet flavors coming from this astonishing mushroom. who acts like a true alchemist.
In the fall, the skin of overripe and botrytized berries turns purplish and their pulp turns into golden jam.
Grape varieties susceptible to noble rot : The semillon dans le bordelais. Il donne quelques-uns des plus grands liquoreux du monde : Sauternes, Barsac, Monbazillac, Loupiac, Cadillac, Sainte Croix du Mont. Sa peau maintenance le rend facilement vulnérable à l’attaque du botrytis. Il est souvent assemblé au sauvignon qui lui apporte de l’acidité et participe à l’équilibre du vin.
Le chenin in the Loire with prestigious appellations: Coteaux du Layon, Quart de Chaume, Bonnezeaux, Vouvray, Montlouis. Its natural acidity guarantees a beautiful balance for these almost immortal wines.
Le riesling en AlsaceEtc. ...
Examples of botrytized wines :
– The Trockenbeerenauslese in Germany;
– tokaji in Hungary;
– Sauternes, Barsac, Cérons, Louiac, Sainte-Croix-du-Mont and Cadillac in Bordeaux;
monbazillac, jurançon in the South-West;
– Coteaux-du-layon, Coteaux-de-l’Aubance, Bonnezeaux, Savennières in the Loire Valley;
- the selections of noble grains in Alsace.
Related articles :
- Wine of overripe grapes
- Sweet wine
- Sweet wine
