Millerandage

Millerandage (or shot berries, hens and chicks and pumpkins and peas) is a potential viticultural hazard problem in which grape bunches contain berries that differ greatly in size and, most importantly, maturity. Its most common cause is cold, rainy or otherwise bad weather during the flowering stage of the vines though other factors, such as boron deficiency or fanleaf degeneration, may also play a role. While millerandage will always cause a drop in yield, its potential impact on wine quality will vary, particularly by grape variety. For some varieties that are prone to uneven ripeness within a cluster, such as Sangiovese, Zinfandel and Gewürztraminer, the development of millerandage may be unfavorable due to "green flavors" from the potentially unripe grapes hidden within the cluster. For other varieties, such as Pinot noir or the Mendoza clone of Chardonnay, wine quality could be improved due to the reduced overall berry size and higher skin to juice ratio. The root cause of millerandage is the poor fertilization of grape flowers during the growing season. While this is most often attributed to bad weather, other factors such as nutritional deficiencies (particularly of the mineral boron which is needed to synthesis the growth hormone auxin and facilitate the movement of sugars in the vine) or viral infections can play a role. For grapevines, flowering occurs usually 8 weeks after the beginning of bud break when the mean daily temperatures hit around . Usually flowering begins at the base of the inflorescence (cluster of flowers) and moves its way to the top. Following the apical dominance of grape vines, the uppermost shoots of the vine will begin flowering first with complete blooming taking place over 7 to 10 days. Ideally the temperature and weather condition for this period should be warm, sunny and dry to insure optimal flowering. For some varieties, such as Zinfandel and Merlot, flowering may be more staggered which poses a greater risk for inclement weather disrupting the process and encouraging millerandage.

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Concepts associés (9)

Cycle annuel de la vigne

vignette|redresse|Grappes de raisin sur un cep de vigne. Le cycle annuel de la vigne est un processus biologique qui se déroule chaque année dans les vignobles. Il commence au printemps par le débourrement des bourgeons et culmine en automne par la chute des feuilles, suivie par la dormance en hiver. Du point de vue de la vinification, chaque étape du processus joue un rôle essentiel dans le développement du raisin pour obtenir des caractéristiques idéales pour la fabrication du vin.

Propagation of grapevines

The propagation of grapevines is an important consideration in commercial viticulture and winemaking. Grapevines, most of which belong to the Vitis vinifera family, produce one crop of fruit each growing season with a limited life span for individual vines. While some centenarian old vine examples of grape varieties exist, most grapevines are between the ages of 10 and 30 years. As vineyard owners seek to replant their vines, a number of techniques are available which may include planting a new cutting that has been selected by either clonal or mass (massal) selection.

Acides du vin

lang=fr|vignette|L'acide malique et l'acide tartrique sont les acides primaires du raisin de cuve. Les acides du vin sont un élément important à la fois dans la vinification et le produit fini du vin. Ils sont présents à la fois dans le raisin et dans le vin, influençant directement la couleur, l'équilibre et le goût du vin, ainsi que la croissance et la vitalité de la levure pendant la fermentation et protégeant le vin des bactéries.