How to Store Fresh Chestnuts? Cold Storage Preservation Techniques for Chestnuts

Fresh chestnuts are in season every autumn and winter, but improper storage and transportation often lead to spoilage and waste. This highlights the importance of cold storage facilities for chestnut preservation. So, how can fresh chestnuts be stored properly to keep them from going bad? And what are the best cold room storage methods for chestnuts?

Why Chestnuts Need Cold Storage

Fresh chestnuts have high moisture content and energy. If you taste one right after harvest, it often lacks sweetness. Many chestnut distributors follow an “industry secret”: when chestnuts are kept in a cold room for about 10–15 days, their starches convert into sugars, gradually becoming sweeter and softer.

Besides improving taste, cold storage also reduces mold, decay, and water loss, ensuring higher quality chestnuts and longer shelf life.

Ideal Temperature and Humidity for Chestnut Cold Rooms

• Recommended temperature: -2℃ to -1℃ (28–30°F)
• Relative humidity: 85%–95% depending on the variety and condition of chestnuts

When stored under these conditions, chestnuts can be preserved for more than 4 months with a good-fruit rate of over 90%.

Proper Stacking and Ventilation

Chestnuts continue to respire after harvest, so poor ventilation can lead to overheating inside the packaging. To prevent this:

• Stack 3–6 bags high only
• Use wooden pallets or mats at the bottom for airflow
• Keep spaces between layers of sacks or boxes for ventilation

This method helps reduce spoilage and ensures even cooling.

Pre-Cooling: The Key Step

Pre-cooling is the most critical part of chestnut storage! Freshly harvested chestnuts must be cooled down quickly to suppress respiration and microbial activity. Without pre-cooling, the chestnuts may deteriorate faster and increase the energy load on the cold storage system.

Rapid pre-cooling also kills most harmful bacteria, creating a better condition for long-term preservation.

Cold Room Operation and Maintenance

• Temperature control: Keep fluctuations within ±1℃ for stability.
• Packaging: Chestnuts lose water easily. Use plastic bags or vacuum packaging to reduce moisture loss. If vacuum sealed, additional humidification is not required.
• Hygiene: Maintain a clean environment inside the cold storage to avoid diseases or mold.

Additional Tips for Growers & Traders

• September–November: Use air-cooled cold rooms for faster sugar conversion.
• December and later: Use tube-type cooling systems (pipe cooling) to maintain humidity and prevent excessive drying, which helps chestnuts retain weight.