Full Moon Harvest: The Science of Darkness

Samos Wine Harvest: Why we pick grapes when the world sleeps. An analysis of enzymatic kinetics, terpene preservation,

and the luminous efficiency of the Full Moon.

The Paradox of the Sun Samos benefits from abundant sunlight, which drives photosynthesis, produces sugars, and enables our Muscat grapes to achieve notable concentration. However, during the Samos wine harvest, intense sunlight can be detrimental. In Mediterranean viticultural regions, daytime temperatures often exceed 30°C, and sometimes 35°C. Harvesting under these conditions initiates chemical reactions that degrade fruit quality before arrival at the winery. At Philia Winery, we deliberately choose to harvest at night. The V'20 harvest (Vintage 2020) was unique, coinciding with the Full Moon and transforming the mountain vineyards of Samos into a luminous landscape. This decision, while visually striking, is fundamentally based on biochemical principles

Thermodynamics and Energy Conservation: The primary and most practical reason for night harvesting is temperature management. Grapes picked at 35°C arrive at the winery with excessive heat, requiring significant energy expenditure to cool the must for controlled fermentation, particularly for white wines such as Muscat, which require temperatures of 16°C to 18°C. Harvesting at night allows grapes to arrive at ambient temperatures of 15°C to 20°C. This passive cooling strategy preserves fruit integrity and considerably reduces the winery's carbon footprint by utilising natural temperature drops rather than industrial refrigeration.

The Challenge of Oxidation (Polyphenol Oxidase) Oxidation poses the greatest risk to white wine quality. Once grapes are picked, and particularly if they are slightly crushed, exposure to oxygen initiates a reaction catalysed by Polyphenol Oxidase (PPO). PPO causes browning of the juice and diminishes freshness. Enzymatic activity is highly temperature-dependent. At 30°C, PPO acts rapidly, converting fresh juice into an oxidised liquid within minutes. At nighttime temperatures below 20°C, the enzyme's kinetic energy decreases substantially, significantly slowing the reaction. Night harvesting, therefore, minimises oxidative enzyme activity, enabling the extraction of juice that stays unspoiled and vibrant.

Volatility of Aromas: Preserving Terpenes Samos Muscat is famous for its aromatic profile, which is attributed to monoterpenes such as linalool, geraniol, and nerol. These compounds are highly volatile, and their vapour pressure increases with temperature.

• Day Harvest: Elevated temperatures cause the most delicate floral top notes to evaporate into the atmosphere before the grapes are even crushed. This results in a significant loss of aromatic compounds.

• Night Harvest: The cool air keeps the terpenes dissolved within the grape matrix and the skin cells. We trap the "precursors" of aroma inside the fruit, ensuring the explosion of scent happens in your glass, not in the vineyard.

Turgidity and Physical Integrity. Plant physiology undergoes notable changes at night. During daytime heat, vines transpire to cool themselves, which can cause grapes to become slightly dehydrated or flaccid. At night, transpiration ceases, and the vine rehydrates, increasing turgor pressure within grape cells. The resulting firmness reduces the risk of berries splitting or becoming damaged during transport, ensuring they remain intact until pressing. Intact skins prevent premature juice release, further protecting against oxidation and uncontrolled microbial activity.

The Full Moon Factor: Optics & Atmosphere While many attribute mystical qualities to the moon—such as the gravitational pull affecting the sap (a concept key to Biodynamics)—in the V'20 harvest, we experienced its practical, physical benefits. Scientifically, a Full Moon provides approximately 0.1 to 0.3 Lux of illuminance. While this seems low compared to sunlight (100,000 Lux), in the pitch black of a mountain, it is significant.

• Visibility: The Full Moon reflects sunlight off the quartz and shale stones in the soil, providing ambient light that aids navigation along Samos' challenging terraces and supplements artificial lighting.

• Climatic Conditions: Full-moon nights in the Aegean are often associated with high-pressure systems, resulting in clear skies and lower humidity. These dry, cool conditions are optimal for harvesting, as they help prevent fungal issues and enable workers to work efficiently without risk of heat exhaustion.

From Quartz to Glass As daybreak approached, we descended from the mountain with crates filled with cool, firm grapes cultivated on ancient quartz and schist soils. These soils store heat during the day and release it at night, creating a distinctive microclimate for the vines. The fruit was processed immediately. The resulting wine demonstrates the effectiveness of this method, exhibiting crystalline acidity, no oxidation notes, and an aromatic intensity achievable only through adherence to scientific principles.

Full moon and head flashlights helping Philia Winery harvesting in Samos

Harvesting by headlight brings significant challenges due to extended shadows, uneven terrain, and physical fatigue. However, the resulting wine, characterised by remarkable vibrancy, demonstrates that the 'Science of Darkness' is fundamental for capturing the authentic qualities of Samos wines.