Millerandage / Shot Berries — Uneven Berry Development

Millerandage (also known as shot berries, hen and chicken, or pumpkins and peas) is a viticultural hazard in which grape bunches contain berries that differ greatly in size and, most importantly, maturity. The small berries are the result of poor fertilization during flowering: without fully developed seeds, the affected berries remain tiny and potentially immature alongside otherwise normal fruit on the same cluster. The term is distinct from coulure, which refers to flowers failing to set fruit entirely. In millerandage, flowers are pollinated but the resulting berries develop without seeds and remain small. Both conditions share environmental triggers and often appear together in difficult vintages, but they are physiologically separate phenomena.

• Occurs during the critical flowering and fruit-set period, typically May to June in the Northern Hemisphere
• Caused by poor fertilization of grape flowers; most often attributed to cold, rainy, or windy weather at bloom
• Coulure refers to flowers that fail to set and fall off entirely; millerandage refers to berries that set but remain small and seedless
• Other contributing factors include boron deficiency, which impairs the synthesis of the growth hormone auxin, and viral infections such as fanleaf degeneration

Millerandage will always have an economic impact through reduced harvest yields, but it does not always harm wine quality. The small, seedless shot berries carry a higher skin-to-juice ratio, which can intensify tannins, color, and flavor compounds in the wine, often desirable in premium red wine production. The challenge lies in the heterogeneity: both berry sizes must reach acceptable ripeness before harvest, and the shot berries may lag behind or, in cooler conditions, never fully ripen, contributing green or astringent notes. Growers must decide whether to remove affected clusters through green harvesting, harvest at a later date to allow shot berries to catch up, or accept the natural concentration that moderate millerandage can provide.

• Smaller berry size increases the skin-to-juice ratio, intensifying tannins, flavors, and color compounds in wine
• Shot berries may remain hard and green throughout the season, introducing high acidity and potentially unripe flavors if not managed
• Growers can remove clusters with heavy millerandage through green harvesting, or delay harvest to allow better ripeness in shot berries
• Some growers deliberately encourage millerandage using chemical sprays, particularly where the quality benefit of reduced berry size is valued

The quality impact of millerandage is strongly variety-dependent. For Pinot Noir and the Mendoza clone of Chardonnay, reduced berry size and elevated skin-to-juice ratio can improve wine quality. In contrast, varieties prone to uneven ripening within a cluster, such as Sangiovese, Zinfandel, and Gewürztraminer, risk developing unfavorable green flavors from potentially unripe shot berries concealed within the cluster. Varieties with naturally staggered flowering windows, including Zinfandel and Merlot, are more exposed to inclement weather disrupting the process and thus more prone to millerandage. In New World regions such as Australia, California, and New Zealand, the presence of millerandage is sometimes viewed positively for a vintage because of the reduced average berry size it produces.

• Pinot Noir and the Mendoza clone of Chardonnay can benefit from millerandage through smaller berries and higher skin-to-juice ratios
• Sangiovese, Zinfandel, and Gewürztraminer are at greater risk of quality loss due to green flavors from unripe shot berries
• Zinfandel and Merlot have staggered flowering, increasing their exposure to weather disruption and millerandage risk
• In Australia, California, and New Zealand, millerandage is sometimes considered a positive sign for vintage quality due to its natural concentration effect

Millerandage has shaped several well-documented Burgundy vintages. In 2002, a cool May retarded flowering, and the crop came in 5.5 percent below the five-year average for red Burgundy, with the wines showing elegant, pure fruit and well-integrated tannins. The 2010 Burgundy vintage saw late, drawn-out flowering through mid-June with coulure and significant millerandage, contributing to very small yields often below 30 hl/ha, yet producers pointed to healthy bunches with tiny grapes as a sign of quality. The 1995 Burgundy vintage experienced millerandage after poor flowering weather in June; many grapes failed to swell properly, producing small berries with a high skin-to-flavoring ratio, though the vintage ultimately delivered a mixed quality record. The 2012 and 2019 vintages in Burgundy also saw notable millerandage from cold, drawn-out flowering conditions.

• 2002 Burgundy: cool May retarded flowering; red crop was 5.5% below the five-year average, yet wines showed elegant, concentrated character
• 2010 Burgundy: late, extended flowering with heavy millerandage; yields often below 30 hl/ha, but bunches were healthy with tiny, concentrated grapes
• 1995 Burgundy: millerandage after poor June flowering resulted in small, skin-rich berries; a small but uneven vintage
• 2012 and 2019 Burgundy: cold, drawn-out flowering triggered coulure and millerandage, significantly reducing yields in both vintages

While millerandage caused primarily by weather cannot be fully prevented, growers have several tools to reduce its severity and manage its effects. Trimming shoot tips near the end of the flowering period reduces competition for sugar resources between developing berries and actively growing shoots, supporting better fruit set. Ensuring adequate leaf coverage for photosynthesis maintains the carbohydrate supply the vine needs during this critical stage. Addressing boron deficiency through appropriate nutrition is important, as boron is needed to synthesize the growth hormone auxin and facilitate sugar movement in the vine. Where millerandage has already occurred, green harvesting to remove heavily affected clusters and careful harvest timing to achieve adequate ripeness in shot berries are the main corrective options.

• Trimming shoot tips near the end of flowering reduces sugar competition between new shoot growth and developing berries
• Adequate leaf coverage ensures sufficient photosynthesis and carbohydrate supply during the critical flowering and fruit-set window
• Boron deficiency should be corrected, as boron is needed for auxin synthesis and sugar movement essential to normal fertilization
• Green harvesting of heavily millerandaged clusters and delayed harvesting of affected fruit are the main in-season management responses

Cool-climate regions where flowering coincides with unpredictable spring weather, particularly Burgundy, Champagne, and Chablis, see millerandage most frequently. The condition has been documented repeatedly in Burgundy vintages including 1995, 2002, 2010, 2012, 2019, and 2024, wherever cold or wet conditions disrupt the flowering window. At a clonal level, the Mendoza and Gingin clones of Chardonnay are notably prone to millerandage and hen-and-chicken berry development; in Margaret River, Western Australia, these clones produce nearly consistent millerandage, which growers and winemakers there associate with high skin-to-juice ratios and concentrated flavor. As climate variability increases, millerandage is being documented more widely across wine regions that do not traditionally expect cool flowering conditions.

• Burgundy is the canonical millerandage region, with cool May-June flowering windows regularly producing affected vintages
• The Mendoza and Gingin Chardonnay clones are specifically prone to millerandage, which is prized in Margaret River for its concentration effect
• Chablis and Champagne also experience millerandage in poor flowering years, as documented in the cool, prolonged 2012 flowering season
• Increasing climate variability is bringing millerandage conditions to regions not historically prone to disrupted spring flowering