Classification
Product TypeRaw Material
Product FormIn-shell (Dried)
Industry PositionPrimary Agricultural Product
Raw Material
Market
In-shell walnuts are a major U.S. tree-nut crop with production concentrated in California’s Central Valley. The product is typically hulled, washed, dried, sized, and packed by handlers, enabling year-round domestic marketing and export shipment from storage. U.S. export programs commonly need to meet destination-specific SPS requirements (e.g., phytosanitary documentation and contaminant/residue compliance) alongside buyer grade/quality specifications. The most material supply risk for U.S. in-shell walnut availability is climate and water stress affecting California orchards.
Market RoleMajor producer and exporter
Domestic RoleImportant domestic snack and ingredient nut, marketed largely via handler/packer programs
SeasonalityHarvest is concentrated in early fall, while year-round availability is supported by dried in-shell storage and staged handler shipments.
Specification
Primary VarietyChandler
Physical Attributes- Sound, intact shells with minimal cracking
- Low foreign matter and field debris
- Free from insect damage and mold
- Uniform sizing to buyer count/size specifications
Compositional Metrics- Moisture management is a key quality parameter for safe storage and reduced mold risk
- Rancidity/oxidation control via dry, cool storage practices
Grades- U.S. grade and size definitions are published by USDA AMS for walnuts in the shell; buyer programs may reference these and add tighter defect tolerances.
Packaging- Bulk bins or totes for domestic redistribution
- Poly-lined cartons or bags for export programs (per buyer/handler specification)
- Clear lot identification on outer packaging for traceability
Supply Chain
Value Chain- Orchard harvest → hulling/washing → drying → sizing/sorting → handler packing → storage → domestic distribution and/or export containerization
Temperature- Maintain cool, dry storage conditions to slow oxidation/rancidity and reduce insect activity
- Avoid temperature/humidity swings that can drive condensation and mold risk
Atmosphere Control- Low-humidity, well-ventilated storage reduces mold and off-odor risk
- Odor-free storage and clean containers protect sensory quality
Shelf Life- Dried in-shell walnuts can be marketed over an extended period when moisture and storage conditions are controlled; quality is sensitive to heat and humidity exposure
Freight IntensityMedium
Transport ModeSea
Risks
Climate HighDrought, water-allocation constraints, and extreme heat in California can sharply reduce yields and disrupt in-shell walnut supply availability and quality, creating fulfillment risk for export programs.Contract with multiple handlers and diversify sourcing within California regions; monitor drought and water-policy signals pre-season and build buffer inventory from early lots when quality permits.
Food Safety MediumMold/mycotoxin (including aflatoxin) and pesticide-residue noncompliance can trigger border holds, rejections, or costly reconditioning in strict markets.Use documented drying/moisture controls, supplier QA programs, and market-appropriate testing plans aligned to destination limits before shipment.
Logistics MediumOcean freight volatility, port congestion, and transit heat/humidity exposure can raise delivered costs and increase quality risk (condensation, off-odors, rancidity) for long-haul container routes.Plan export programs with flexible sailing windows, use clean/dry containers, and apply robust moisture/temperature risk controls in stuffing and storage.
Trade Policy MediumRetaliatory duties or sudden tariff changes in key destination markets can rapidly shift demand away from U.S. origin and disrupt established export channels.Diversify destination mix, track policy updates in priority markets, and structure contracts with tariff-change clauses where feasible.
Sustainability- Water stewardship and groundwater management in California orchard systems
- Climate resilience planning (heat, drought, wildfire smoke) for orchard and post-harvest operations
- Pesticide-use scrutiny and residue compliance for export markets
Labor & Social- Agricultural labor compliance (wages, working time, and—where applicable—housing/transport for seasonal crews)
- Worker heat-stress and wildfire smoke exposure risks during field operations and harvest season
Standards- BRCGS Food Safety (buyer-required in some channels)
- SQF
- FSSC 22000
- HACCP / FSMA-aligned preventive controls programs (buyer audit expectations vary by channel)
FAQ
When is the main U.S. in-shell walnut harvest season?Harvest is concentrated in early fall, typically September through November in California’s Central Valley, with peak activity around October. Year-round availability is supported by post-harvest drying and storage managed by handlers.
What documents are commonly needed to export U.S. in-shell walnuts?Common documents include a commercial invoice, packing list, and bill of lading. Many destinations also require a phytosanitary certificate issued through USDA APHIS, and some buyers or regimes request a certificate of origin.
Which U.S. organizations publish official references for walnut grades and phytosanitary export certification?USDA AMS publishes U.S. grade standards used as references for walnuts, and USDA APHIS provides the official framework and services for phytosanitary certification used for plant-product exports when destinations require it.