Glazing covers frozen shrimp with a thin, even layer of ice that protects it from drying out and oxidising during cold storage and transport. The glazing rate depends mainly on how cold the shrimp is, how cold the water is and how long the shrimp is in contact with it. GLORY glazers control all three automatically, reaching 8 to 28% in a single pass and up to about 45% with triple glazing.
1. What glazing does and why the rate matters
A glaze is a protective shell of ice. It keeps air away from the shrimp surface, so the product does not dehydrate (freezer burn) or oxidise during months of storage and long sea freight. A good glaze also gives the clear, glossy look that buyers expect.
The glazing rate is agreed with the buyer and written into the specification. Too little glaze and the product is less protected; too much and the buyer pays for water, which leads to claims and, in some markets, problems with net-weight rules. An uneven glaze is the most expensive case of all: to be sure every carton meets the minimum, the plant gives away product on many of them.
Read more
That is why the target is not simply a high glazing rate, but the right rate, held steady from the first carton of the shift to the last.
2. What controls how much glaze a shrimp picks up
| Factor | Effect on the glaze | How a GLORY line controls it |
|---|---|---|
| Product temperature | Colder shrimp freeze more water onto the surface | The IQF freezer delivers product at a stable, low core temperature into the glazer |
| Water temperature | Colder water freezes faster and builds a thicker layer | A built-in chiller adjusts the water temperature automatically, typically between about 0 and +10 °C |
| Contact time | Longer dipping or spraying adds more water | Belt speed is set by program and follows the actual production load |
| Product size and shape | Small shrimp have more surface per kilogram and pick up more glaze | Recipes for each product and size are stored in Master AutoCell® |
| Number of passes | Each extra pass adds a new layer | Double and triple glazing with hardening and re-freezing between layers |
When a frozen shrimp meets chilled water, a layer of water freezes onto its surface. How thick that layer becomes depends on a few factors, and a glazer must control them together:
Read more
Because these factors interact, manual adjustment rarely keeps the rate stable for long. GLORY lines measure and adjust them automatically, which is the main reason the glazing rate stays on target.
3. Single, double or triple glazing?
One glazing pass is enough for many products. When buyers ask for a heavier glaze, the line adds passes, each followed by hardening and re-freezing so the next layer has a solid base.
| Glazing | Typical final glaze* | Line after the IQF freezer |
|---|---|---|
| Single | 8 to 28% | Glazer → hardening conveyor → re-freezer |
| Double | up to about 30% | Two glazing passes, each hardened and re-frozen |
| Triple | up to about 45% | Three glazing passes, each hardened and re-frozen |
Read more
* Reference: peeled shrimp (PD) of 31 to 40 pieces per pound. The achievable rate depends on product size, type and temperature. A GLORY recirculation design can let the same glazer, hardening conveyor and re-freezer serve more than one pass, which saves investment, floor space and running costs.
4. Why harden and re-freeze between layers
- 1GlazingA precise layer of chilled water is applied.
- 2Hardening conveyorThe layer begins to set and excess water drains away.
- 3Re-freezerThe glaze is frozen solid and the core is brought back down.
- 4Next pass or packingThe product has a firm base for the next layer, or is ready to pack.
Right after glazing, the new water layer is still soft. If the product goes straight into another glazing pass or into packing, that layer is washed off, cracks or makes the shrimp stick together. Each glazing pass is therefore followed by two steps:
Read more
The hardening conveyor also keeps loose water out of the re-freezer. Without it, water freezes onto the evaporator and the belt, which shortens running time between defrosts and can damage the belt.
5. What a GLORY glazer does differently
Choose the product, size and target glazing rate; Master AutoCell® adjusts water temperature and belt speed and keeps the rate on target as the load changes, without operator adjustment.
The built-in chiller is cooled by propylene glycol from the plant. No flake ice and no direct ammonia or Freon inside the glazer.
GLORY spray nozzles in SUS 316 can use up to 42% less water than conventional nozzles while covering every piece evenly.
Shrimp arrive from the IQF already separated and each layer is hardened before the next, so pieces stay loose.
Flat stainless surfaces are easy to clean, and transparent covers let operators watch the product without opening the glazer.
GLORY’s specially designed flighted incline conveyor releases every piece cleanly, so no glazed product is lost between conveyors.
6. Common glazing problems and how to avoid them
| Problem | Usual cause | Solution |
|---|---|---|
| Glazing rate too low | Product enters the glazer too warm, or water too warm | Stable IQF outlet temperature and automatic water temperature control |
| Uneven glaze between cartons | Manual settings that do not follow changes in load or size | Glazing rate held by program and adjusted to the actual throughput |
| Shrimp stick together | Soft glaze, or product already clumped at the IQF outlet | Individually separated product from the IQF; hardening and re-freezing after every pass |
| Glaze cracks or peels | Layer not fully frozen before handling | Re-freezer sized for the glazing load |
| Ice build-up in the re-freezer | Loose water carried in from the glazer | Hardening conveyor that drains and sets the glaze first |
7. Frequently asked questions
What glazing rate can a single pass reach?
From 8 to 28% depending on product size and type, with peeled shrimp of 31 to 40 pieces per pound as the reference.
How do you reach 35 to 45% glaze?
With double or triple glazing. Each layer is hardened and re-frozen before the next, which allows a heavy glaze without clumping or washing off.
Do I need flake ice or a separate water chiller?
No. GLORY glazers have a built-in chiller cooled by propylene glycol and adjust the water temperature automatically. Chilled water is only needed for the optional spray stage.
Can the glazing rate be changed during production?
Yes. Select another recipe or target in Master AutoCell®; water temperature and belt speeds follow automatically.
Can GLORY add glazing to an existing freezing line?
Yes. A glazer, hardening conveyor and re-freezer can be added after an existing IQF freezer, and a second pass can be added for double glazing.
Does glazing work for products other than shrimp?
Yes. The same principle is used for fish, squid, scallops and other frozen seafood; GLORY sets up recipes for each product.
Need a specific glazing rate?
Tell us your product, size and target glazing rate. GLORY engineers will propose the glazing and re-freezing configuration for your line.
