What Is Glazing on Frozen Shrimp?
Glazing is a thin coating of ice applied to IQF (individually quick frozen) shrimp immediately after freezing. The glaze serves a critical protective function: it creates a moisture barrier that prevents freezer burn, oxidation, and dehydration during storage and transport. Without adequate glazing, frozen shrimp develop black spots, lose their translucent appearance, and suffer textural degradation — all of which reduce their market value.
However, from a buyer's perspective, ice is not shrimp. A 10 kg bag of frozen shrimp with 20% glazing contains only 8 kg of actual shrimp. This is why glazing percentage is one of the most important specification parameters when purchasing frozen shrimp in bulk.
Glazing Percentage: How It Works
Glazing percentage is expressed as a proportion of the total (gross) frozen weight:
Glaze % = (Gross Weight − Net Drained Weight) ÷ Gross Weight × 100
Example: A 10 kg box of IQF vannamei shrimp, after thawing and draining for 2 minutes, yields 8.5 kg of drained shrimp weight. The glazing percentage is (10 − 8.5) ÷ 10 × 100 = 15%.
The net drained weight is what you are actually buying — protein, not ice. When comparing prices from different suppliers, always convert to a net drained weight basis for accurate comparison.
Acceptable Glazing Percentages by Market
There is no single global standard for shrimp glazing, but the following norms reflect actual industry practice in major import markets:
| Market / Standard | Typical Acceptable Glaze Range | Notes |
|---|---|---|
| USA (USDC / processor spec) | 8% – 15% | Many US retail specs cap glaze at 10% |
| European Union | 10% – 20% | EU labeling requires net drained weight on retail packs |
| Japan | 8% – 12% | Strict; retailers often specify ≤10% |
| Middle East (GCC) | 15% – 25% | Higher glaze accepted; price sensitivity drives preference |
| Food service / HORECA | 10% – 20% | Chefs care about yield; specify 10–15% max |
| Food manufacturing | 15% – 25% | Further processing reduces glaze impact on yield |
How to Specify Glazing on Your Purchase Order
When placing an order for frozen shrimp, always include a glazing specification in your purchase order or product specification sheet. Common ways to specify:
- "Maximum 15% glazing" — sets an upper limit; supplier must glaze at or below this level
- "Net drained weight minimum 85% of gross weight" — equivalent to maximum 15% glaze; many buyers prefer this phrasing
- "Net drained weight as per CODEX STAN 92" — references the Codex Alimentarius standard for frozen shrimp, which specifies a minimum drain weight of 80% (equivalent to maximum 20% glaze)
- "IQF shrimp, 10% glaze tolerance ±2%" — specifies a target with tolerance for production variation
Your supplier should confirm the glazing level on the product specification sheet (PSS) and Certificate of Analysis (COA) for each production lot.
How to Verify Glazing on Arrival
To verify the glazing percentage of an incoming shipment:
- Weigh the frozen product gross weight (e.g., 2 kg sample from the box)
- Place the frozen shrimp in a clean colander over a bowl
- Allow to thaw and drain at room temperature for exactly 2 minutes (some standards specify slightly different times — follow your specification)
- Weigh the drained shrimp
- Calculate: (Gross − Drained) ÷ Gross × 100 = Glaze %
For import receiving and quality control, pull samples from at least 3 random cartons per container and average the results. A result within ±2–3% of your specification is typically acceptable given production variability.
Under-Glazing vs Over-Glazing: Both Are Problems
Over-glazing (above your specification) is the more common complaint. It reduces your net protein yield per kg, effectively raising your true cost per kg of shrimp. On a 20 MT container, a supplier applying 20% glaze instead of your specified 15% means you receive 1 MT less shrimp than you paid for — a significant financial loss.
Under-glazing is less financially problematic but damages product quality. Shrimp with insufficient glaze (<8%) shows freezer burn symptoms: black spots, white desiccated patches, off-colour appearance, and loss of texture after thawing. Under-glazed shrimp has a shorter frozen shelf life and higher rate of consumer complaints.
Glazing Standards at Hanuman Seafood
At Hanuman Seafood, our standard glazing specification for IQF vannamei and black tiger shrimp is 12–15% unless the buyer specifies otherwise. For buyers in Japan or the US retail market, we produce to a 10% glaze specification on request. All shipments include a COA confirming actual net drained weight as measured in our in-house QC laboratory before container loading.
If your current supplier is not providing COA data on net drained weight, or if you are receiving product above your specified glazing level, contact our export team to discuss a trial container with verified specification compliance.
