millerandage
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Millerandage (or shot berries, hens and chicks and pumpkins and peas) is a potential
viticultural hazard This is a list of diseases of grapes (''Vitis'' spp.). Bacterial diseases Fungal diseases Miscellaneous diseases and disorders Nematodes, parasitic Phytoplasma, virus and viruslike diseases See also *'' Ampeloglypter ater'' *'' Am ...
problem in which
grape A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus ''Vitis''. Grapes are a non- climacteric type of fruit, generally occurring in clusters. The cultivation of grapes began perhaps 8,000 years ago, ...
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 A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...
stage of the vines though other factors, such as
boron Boron is a chemical element with the symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the ''boron group'' it has th ...
deficiency or fanleaf degeneration, may also play a role.J. Robinson (ed) ''"The Oxford Companion to Wine"'' Third Edition pgs 77, 291, 322, 443 Oxford University Press 2006 While millerandage will always cause a drop in yield, its potential impact on wine quality will vary, particularly by
grape variety This list of grape varieties includes cultivated grapes, whether used for wine, or eating as a table grape, fresh or dried (raisin, currant, sultana). For a complete list of all grape species including those unimportant to agriculture, see Viti ...
. For some varieties that are prone to uneven
ripeness In United States law, ripeness refers to the readiness of a case for litigation; "a claim is not ripe for adjudication if it rests upon contingent future events that may not occur as anticipated, or indeed may not occur at all." For example, if a ...
within a cluster, such as
Sangiovese Sangiovese (, also , , ) is a red Italian wine grape variety that derives its name from the Latin ''sanguis Jovis'', "the blood of Jupiter". Though it is the grape of most of central Italy from Romagna down to Lazio (the most widespread grape i ...
,
Zinfandel Zinfandel (also known as Primitivo) is a variety of black-skinned wine grape. The variety is grown in over 10 percent of California vineyards. DNA analysis has revealed that it is genetically equivalent to the Croatian grapes Crljenak Kaštel ...
and
Gewürztraminer Gewürztraminer () is an aromatic wine grape variety, used in white wines, and performs best in cooler climates. In English, it is sometimes referred to colloquially as Gewürz (; although this is never the case in German, because "Gewürz" me ...
, 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 Pinot Noir () is a red-wine grape variety of the species ''Vitis vinifera''. The name may also refer to wines created predominantly from pinot noir grapes. The name is derived from the French language, French words for ''pine'' and ''black.' ...
or the Mendoza clone of
Chardonnay Chardonnay (, , ) is a green-skinned grape variety used in the production of white wine. The variety originated in the Burgundy wine region of eastern French wine, France, but is now grown wherever wine is produced, from English wine, Englan ...
, wine quality could be improved due to the reduced overall berry size and higher skin to juice ratio.


Causes

The root cause of millerandage is the poor fertilization of grape flowers during the
growing season A season is a division of the year marked by changes in weather, ecology, and the amount of daylight. The growing season is that portion of the year in which local conditions (i.e. rainfall, temperature, daylight) permit normal plant growth. Whil ...
. 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 Auxins (plural of auxin ) are a class of plant hormones (or plant-growth regulators) with some morphogen-like characteristics. Auxins play a cardinal role in coordination of many growth and behavioral processes in plant life cycles and are essenti ...
and facilitate the movement of
sugars Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose, fructose, and galactose. Compound sugars, also called disaccharides or double s ...
in the vine) or viral infections can play a role.


Flowering and fruit set

For grapevines, flowering occurs usually 8 weeks after the beginning of
bud break The annual growth cycle of grapevines is the process that takes place in the vineyard each year, beginning with bud break in the spring and culminating in leaf fall in autumn followed by winter dormancy. From a winemaking perspective, each step ...
when the mean daily temperatures hit around . Usually flowering begins at the base of the
inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...
(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 Merlot is a dark blue–colored wine grape variety, that is used as both a blending grape and for varietal wines. The name ''Merlot'' is thought to be a diminutive of ''merle'', the French name for the blackbird, probably a reference to the ...
, flowering may be more staggered which poses a greater risk for inclement weather disrupting the process and encouraging millerandage. Some growers may try to encourage more synchronized flowering with the use of chemical treatments, such as
cyanamide Cyanamide is an organic compound with the chemical formula, formula carbon, Cnitrogen, N2hydrogen, H2. This white solid is widely used in agriculture and the production of pharmaceuticals and other organic compounds. It is also used as an alcoho ...
.R. Jackson ''"Wine Science: Principles and Applications"'' Third Edition pgs 70-72 Academic Press 2008 Following flowering, the flowers of the grape vine go through pollination and fertilization over the next 2 to 3 days. Here is another opportunity where incremental weather can influence the outcome with temperature drops below potentially damaging the
ovules In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the ''integument'', forming its outer layer, the ''nucellus'' (or remnant of the megasporangium), and the fe ...
of the flowers before they can be fertilized. Since grapevines are
hermaphroditic In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many taxonomic groups of animals (mostly invertebrates) do not have separ ...
(containing both male and female parts) and usually rely on
self-pollination Self-pollination is a form of pollination in which pollen from the same plant arrives at the Stigma (botany), stigma of a flower (in flowering plants) or at the ovule (in gymnosperms). There are two types of self-pollination: in autogamy, pollen i ...
, the presence of wind to circulate pollen or insects usually doesn't influence the success or failure of the pollination stage. While not as influential as temperature, the presence of rain can "wash off" the pollen from the stigma or greatly dilute the stigmatic fluid, causing the pollen to absorb too much water, swelling and bursting before it reaches the ovules.Winkler AJ, Cook JA, Kliere WM and Lider LA ''General Viticulture'' 2nd Edition, pgw 126-133 University of California Press. 1974 . Even in the most ideal conditions, usually only 20-30% of flowers develop into mature fruit with fully developed seeds and auxin production. If even fewer berries develop, the condition of
coulure Coulure (pronounced coo-LYUR) is a viticultural hazard that is the result of metabolic reactions to weather conditions that causes a failure of grapes to develop after flowering. In English the word ''shatter'' is sometimes used. Coulure is trigge ...
emerges while for developed berries, the number of seeds (or their absence) will influence the resulting size of the berries. Millerandge most often occurs when the partially fertilized grapes do not develop any seeds, leaving small (and potentially immature) berries present in a cluster of larger, otherwise mature berries.


Influence on wine quality

While millerandage will always have an economic impact in reduced
harvest Harvesting is the process of gathering a ripe crop from the fields. Reaping is the cutting of grain or pulse for harvest, typically using a scythe, sickle, or reaper. On smaller farms with minimal mechanization, harvesting is the most labor-i ...
yields, it may not always have a negative impact on the resulting quality of the wine. In some areas, such as the New World wine regions of
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
,
California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
and
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
, the presence of millerandage in the a vineyard can be seen as a positive quality for a
vintage Vintage, in winemaking, is the process of picking grapes and creating the finished product—wine (see Harvest (wine)). A vintage wine is one made from grapes that were all, or primarily, grown and harvested in a single specified year. In certa ...
due to the reduced average berry-size. Some growers will even use chemical sprays to deliberately encourage millerandage.T. Stevenson, ed. ''The Sotheby's Wine Encyclopedia (5th Edition)'' pg 23 Dorling Kindersley (2011) However, the small, seedless berries may never fully ripen and stay hard and green (with high
acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...
) throughout the growing season. Some growers may choose to remove clusters with high preponderance of millerandge through green harvesting or choose to harvest the entirety of the crop later at higher ripeness levels to balance the high acid and potentially "green flavors" of the shot berries. Other growers will remove the grape post-harvest at a sorting table along with other MOG.Clive Coates ''An Encyclopedia of the Wines and Domaines of France'' pgs 16 & 520 University of California Press; First Printing edition (June 2001)


References

{{Viticulture Viticulture Grape diseases