How to properly store grain in big bags
Storing grain in big bags is a common practice among farmers and grain traders. Flexible containers take up minimal space when stored empty, are easily moved by a forklift, and are significantly cheaper than metal silos. But to prevent the grain from spoiling, a few key rules must be followed.
Grain preparation before storage
The main enemy of grain during storage is moisture. Before filling into a big bag, the grain must be dried to safe moisture levels:
| Crop | Max. moisture | Storage term | Recommended big bag |
|---|---|---|---|
| Wheat | 14% | up to 12 months | 1000–1500 kg with liner |
| Corn | 14% | up to 8 months | 1000 kg with liner |
| Barley | 14% | up to 12 months | 1000 kg |
| Sunflower | 8% | up to 6 months | 500–750 kg with liner |
| Rapeseed | 8% | up to 6 months | 750–1000 kg with liner |
| Soybeans | 12% | up to 10 months | 1000 kg with liner |
Grain with moisture above safe levels will start to 'sweat' when stored in a closed container — emitting heat, forming condensation, and eventually molding. Even 1–2% of excess moisture can spoil a batch in a few weeks.
Is a liner needed or not?
This is the most common question. The answer depends on storage conditions:
Liner is needed
Outdoor storage or under a canopy. Oilseeds (sunflower, rapeseed, soybeans). Long-term storage over 3 months. High level of atmospheric humidity in the region.
Without liner is fine
Storage in a dry indoor warehouse. Grains with low moisture (up to 12%). Short-term storage up to 1–2 months before shipment.
A polyethylene liner 80–100 µm thick fully protects grain from external moisture. But there is a catch: the liner also does not let moisture out. Therefore, storing grain with above-standard moisture in a lined big bag is strictly prohibited.
Where and how to place big bags
- ✔On pallets or flooring — never place a big bag directly on the ground or concrete floor (condensation from below)
- ✔Leave a 10–15 cm gap between big bags for air circulation
- ✔Stacking — no more than 2 tiers for 4-loop big bags with SF 6:1
- ✔Protection from direct sunlight — UV degrades polypropylene (even with UV stabilizers)
- ✔Protection against rodents — pallets 15+ cm high, ultrasonic repellers
- ✔Temperature control: optimally +5…+15°C, maximum +25°C
Which big bag to choose for grain
Recommendations depend on batch volume and conditions:
| Parameter | Recommendation |
|---|---|
| Load capacity | 1000 kg — optimal balance of price and convenience |
| Number of loops | 4-loop — if you will stack; 2-loop — for single placement |
| Top | With filling spout (or skirt) — protection from precipitation |
| Bottom | Flat — for storage; with discharge spout — for feeding onto a conveyor |
| Liner | 80–100 µm PE — for outdoor storage and oilseeds |
| Safety factor | 6:1 — if you plan to reuse |
Common mistakes when storing grain in big bags
Filling with moist grain
Check the moisture of each batch before filling. Do not trust 'by touch' — use a meter.
Storing on bare ground
Only on pallets or wooden flooring. Concrete and soil draw moisture.
Stacking 3+ tiers
Maximum 2 tiers for 4-loop SF 6:1. One tier — if 2-loop or SF 5:1.
Storing under direct sunlight for months
Even with UV stabilizers, PP degrades. Cover with an awning or store indoors.
Reuse without inspection
Before reuse, check loops, seams, and fabric for damage.
Frequently Asked Questions
How much grain does one big bag hold?
Depends on the crop. Wheat (~750 kg/m³): a 90×90×130 cm big bag holds ~1000 kg. Sunflower (~350 kg/m³): the same big bag will hold ~370 kg — a larger container or lower claimed capacity is needed.
Can grain be stored in big bags in winter?
Yes, polypropylene withstands temperatures down to −40°C. The main thing is that the grain must be dry before filling. With temperature fluctuations (day/night), condensation can form — use a liner.
How long can grain be stored in big bags?
Provided proper moisture and protection from precipitation: wheat, barley — up to 12 months; corn — up to 8 months; sunflower, rapeseed — up to 6 months. For longer storage, silos are recommended.
Is ventilation needed when storing in big bags?
Polypropylene fabric lets air through — this is natural 'breathable' ventilation. But if a PE liner is used, the container becomes airtight. In this case, the grain must be perfectly dry.
For the agricultural sector we offer big bags for grain wholesale with laminated fabric and polyethylene moisture liners. In stock: four-loop 1000 and 1500 kg models built for long-term outdoor storage, with nationwide delivery during the harvest peak.