Stainless Steel Gastronorm Pans (Australia): The Science of Size, Depth & Cooling Compliance
Search intent: informational → commercial investigation. This guide explains GN sizes, depth physics, and FSANZ cooling rules so Australian cafés, takeaways, schools, hospitals and caterers can speed service, meet temperature targets, and standardise mise‑en‑place. It includes size charts, printable checklists, a simple cooling estimator, a real‑world case study and product shortlists.
- GN 1/1 = 530 × 325 mm is the base module; other sizes are multiples/fractions (2/1, 2/3, 1/2, 1/3, 1/4, 1/6, 1/9). Choose depth by cooling need, not just capacity.
- FSANZ cooling targets: 60 °C → ≤ 21 °C within 2 h; then ≤ 5 °C within 4 h (total ≤ 6 h). Keep evidence via cooling logs.
- Shallow pans + split batches are the fastest path to compliant cooling and stable cold‑holding on the warmest shelf.
- 304 stainless GN gives widest compatibility across ovens, fridges, bain maries and dishwashers; use lids for storage and transport, not when fast‑cooling.
What exactly is a Gastronorm pan (and why your whole line depends on it)
Gastronorm (GN) is a European modular sizing system for containers and trays used across professional kitchens worldwide. The base size is GN 1/1 (530 × 325 mm); other sizes are precise fractions or multiples so pans tessellate without wasted space in compatible equipment—prep fridges, combi ovens, bain maries, hot bars, holding cabinets, trolleys and shelving. The standardisation keeps your workflow predictable and lets you scale a recipe simply by swapping pan depth or count.
GN size & depth quick chart
| GN size | External (mm) | Typical depths (mm) | Use cases |
|---|---|---|---|
| 2/1 | 650 × 530 | 20, 40, 65, 100, 150, 200 | Batch roasts; high‑volume combi/roll‑in |
| 1/1 (base) | 530 × 325 | 20, 40, 65, 100, 150, 200 | Universal: roasts, chill, hot holding |
| 2/3 | 354 × 325 | 20–150 | Sides, proteins; two per 1/1 width |
| 1/2 | 325 × 265 | 20–200 | Batch sauces; shallow for fast cooling |
| 1/3 | 325 × 176 | 20–150 | Toppings; portioned proteins |
| 1/4 | 265 × 162 | 20–150 | Sauces, garnishes, sides |
| 1/6 | 176 × 162 | 20–150 | Condiments, mise trays |
| 1/9 | 108 × 176 | 20–100 | Small toppings, spices |
Dimensions follow the EN 631 modular system; always check your equipment manual for maximum pan depth and load lines.
Why stainless steel GN is the “all‑terrain” option
- Heat‑safe for ovens and bain maries; cold‑safe for fridges/freezers.
- Durable, non‑reactive (304/18‑8) and easy to sanitise in commercial dishwashers.
- Works with food prep fridges and bain maries without changing vessels mid‑flow.
Clear polycarbonate pans are great for cold display and storage; avoid direct heat. Stainless is the safe universal default for hot–cold–wash cycles.
- All Gastronorm Pans · Stainless Steel GN Pans
- GN 1/1 (530 × 325 mm) · GN 1/4 · GN 2/1
- Lids, racks & accessories for storage and hot holding
Depth physics 101: why a 65 mm pan cools faster than a 150 mm pan
Cooling speed is controlled by heat transfer. In practice, two variables dominate:
- Food depth / thickness — the centre of a thicker mass takes longer to lose heat. Shallow, spread‑out layers cool faster because the surface‑area‑to‑volume ratio improves.
- Airflow around the pan — cold air must move freely across the surface. Stacking pans, covering tightly, or blocking return air slows cooling dramatically.
Illustrative cooling comparison (same food mass)
| Pan depth | Layer thickness | Centre temp to 21 °C | Centre temp to 5 °C | Risk |
|---|---|---|---|---|
| 150 mm (full) | ~120–130 mm | Often > 2 h | May exceed 4 h | Fails FSANZ without blast chill/stir |
| 100 mm (¾ full) | ~70–80 mm | Near 2 h with venting | Borderline without rotation | Needs active monitoring |
| 65 mm (½–⅔ full) | ~30–40 mm | < 2 h typical | < 4 h typical | Best passive cooling |
Indicative only; your times depend on product density, start temperature, stirring, and cabinet type. Always verify with a probe.
Do’s & don’ts that change outcomes
- Do split a pot into multiple 65 mm pans; spread no more than 40 mm deep.
- Do vent steam while cooling (loose covers/film lifted) to avoid condensation heat trap.
- Don’t stack pans while cooling; don’t block return air or place pans above load lines.
- Don’t fill a deep pan “to the brim” for cooling; use depth for storage, not fast pull‑down.
Cooling & reheating rules that never change (FSANZ)
Cooling targets (prove with logs)
- From 60 °C to ≤ 21 °C in 2 hours, then to ≤ 5 °C within a further 4 hours (total ≤ 6 h).
- Alternative methods are acceptable if you can demonstrate safety (evidence beats opinion).
- Keep a probe thermometer (± 1 °C) and record the warmest point in the food.
Reheating & holding
- Reheat rapidly to ≥ 60 °C before hot‑holding; never “slow‑warm” in display units.
- Hot‑hold at ≥ 60 °C (bain maries, hot bars) and log the coldest point on a tray.
- Using time as a control? Apply the 2‑hour/4‑hour rule; time in the 5–60 °C danger zone is cumulative across prep, display and service.
These practices align with Food Standards Australia New Zealand (FSANZ) food‑safety guidance and council inspections. See the official links in “Sources”.
- Cooling log sheets with time/temperature checkpoints.
- Probe accuracy (ice‑point) check within ± 1 °C, weekly or after drop events.
- 2‑hour/4‑hour labels on trays when using time as a control.
Pick the right GN material & finish (and when stainless wins)
| Material | Heat/cold compatibility | Durability & hygiene | Best for | Notes |
|---|---|---|---|---|
| 304 stainless steel (18/8) | Oven, bain marie, fridge/freezer, dishwasher | High corrosion resistance; smooth, non‑porous | Universal hot/cold, cooling + hot holding | Most versatile; safe for acidic/salty foods |
| 18/0 stainless (magnetic) | Similar to 304; magnetic attraction | Good; slightly less corrosion resistance | Induction rails, cold rails | Use where magnetic coupling is useful |
| Polycarbonate (clear) | Fridge/freezer, dishwasher; no direct heat | Impact‑resistant; transparent for inventory | Cold wells, salad bars, storage | Great visibility; avoid hot ovens/hobs |
| Melamine | Ambient/cold display | Hard‑wearing surface; not for heating | Buffet display (cold) | Check maker’s dishwasher guidance |
| Aluminium (anodised) | Hot/cold; high conductivity | Good heat transfer; watch for corrosion | Rapid chilling; bakery trays | Use food‑safe finishes; avoid reactive contact |
For one‑vessel workflow (cook → cool → store → reheat/hold), 304 stainless GN is the safest “one pan to rule them all”.
Cooling workflow that actually works on a Friday night
1) Portion & spread
Move hot food into multiple 65 mm pans, layer ≤ 40 mm. Avoid overfilling deep pans for cooling.
2) Vent & move air
Place pans where cold air circulates; lift film/lids to vent steam. Don’t stack while cooling.
3) Stage & rotate
Stagger into fridge/blast chiller; rotate pans at 30–45 min if centres lag.
4) Probe & log
Probe centre of the thickest area: 60→21 °C (≤ 2 h), then 21→≤5 °C (≤ 4 h). Record corrective actions.
5) Lid & label
Once ≤ 5 °C, fit lids, label time/date and store below load lines.
Simple cooling estimator (for planning depth)
This back‑of‑house estimator helps you plan pan depth before a big cook. It’s a rule‑of‑thumb—always verify with a probe and your cooling logs.
Rule‑of‑thumb only, tuned for shallow layers (≤ ~40 mm) of sauces/stews. For dense roasts or deep liquids, use a blast chiller or reduce thickness.
Printable templates — cooling, reheating & thermometer checks
A) Cooling log (peak periods)
| Batch / item | Pan (size × depth) | Loaded at | Centre ≤ 21 °C (time) | Centre ≤ 5 °C (time) | Corrective action | Initials |
|---|---|---|---|---|---|---|
| Beef curry | GN 1/2 × 65 mm | __ : __ | __ : __ | __ : __ | Stir / split / move | __ |
| Tomato sauce | GN 1/1 × 40 mm | __ : __ | __ : __ | __ : __ | Rotate / vent | __ |
B) Reheat & hot‑hold check
| Item | Reheat to ≥ 60 °C at | Holding unit | Coldest point (°C) | Time | Action if < 60 °C |
|---|---|---|---|---|---|
| Gravy (GN 1/3) | __ : __ | Bain marie | __ | __ : __ | Adjust / discard / reheat |
C) Probe accuracy (ice‑point)
| Date | Method | Reading | Pass/Fail | Action |
|---|---|---|---|---|
| __ / __ | Ice‑point 0 °C | __ °C | Pass / Fail | Re‑calibrate or note offset |
Match pan depth to equipment & service (with product links)
Chill & store (back‑of‑house)
- Food Prep Fridges — cold‑well rails accept GN pans; keep layers shallow for the warmest shelf.
- Stainless GN (65 mm) — default for fast cooling and stable holding.
Hot‑hold & pass
- Bain Maries — hold ≥ 60 °C with lids to reduce evaporation and heat stress.
- Lids & racks — use lids for storage/holding, not during rapid cooling.
Case study — “From failed cooling logs to full compliance in 10 days”
Setting: a Western Sydney school canteen serving 900 meals/day. Inspection flagged cooling log failures on Monday batch pasta—centre temps still 9–10 °C next morning. Staff stored nightly batches in deep pans stacked to save space.
What we found
- GN 1/1 × 150 mm pans filled > 120 mm; stacked while cooling; return air blocked.
- Fridge ran at 3–4 °C but warmest shelf food failed 60→21→5 °C targets.
- No probe on the line; logs based on cabinet dials, not food temperatures.
What we changed (10‑day plan)
- Switched to GN 65 mm pans and split batches; max 40 mm layer.
- Added wire racks between pans to keep air moving; banned stacking while cooling.
- Introduced probe checks (± 1 °C) and refreshed logs with corrective‑action column.
- Re‑mapped the fridge so hot product sits where airflow is best (not behind load lines).
Results (weeks 2–3)
- All batches reached ≤ 21 °C within 90–120 min; ≤ 5 °C within the next 120–180 min.
- Zero corrective actions needed by week 3; inspection passed with notes “improved evidence”.
- Service quality improved: sauces kept body; reheats were consistent in bain maries.
Your outcomes depend on product density, pan fill, airflow and staff discipline. The fastest wins usually come from pan depth + airflow + probe logs, not from changing fridges.
FAQs — the short, honest answers
1) Can I cool in 150 mm pans if I don’t fill to the top?
Yes, but treat “fill height” as the metric. Keep the layer roughly ≤ 40 mm for passive cooling unless you have blast chill or active stirring. Verify with a probe.
2) Should I cover pans while cooling?
Vent steam during the cooling phase so heat can escape; tighten lids once ≤ 5 °C to prevent contamination and drying.
3) Do I need stainless, or can I use plastic GN for hot food?
Use stainless for hot cooking/holding and rapid temperature swings. Clear plastic is excellent for cold storage and display, but avoid direct heat.
4) How do I prove cooling compliance to council?
Keep cooling logs with start times, checkpoints and corrective actions; calibrate your probe ± 1 °C; show that you control depth/airflow and that staff follow the plan.
5) Why are my cold wells safe but my upright fridge logs fail?
Cold rails blow chilled air across shallow pans; upright fridges rely on air circulation that deep, densely packed pans can block. Adjust depth and spacing.
Free “GN Depth Map & Cooling Log Pack” for your menu
Send us photos of your current pan setup (sizes, depths, where they sit in each cabinet) and your busiest menu items. We’ll reply with a one‑page depth map, a cooling log template tuned to your service, and a quick product shortlist to fix weak spots:
- Stainless Steel GN Pans — 20–200 mm depths
- GN lids & racks — tidy, hygienic, efficient
- Food Prep Fridges & Bain Maries — match equipment to pans
Official sources & further reading (stable links)
- FSANZ — Cooling and reheating food (60→21 °C in 2 h; 21→≤ 5 °C in 4 h): foodstandards.gov.au/business/food-safety/cooling-and-reheating-food
- FSANZ — Keeping food at the right temperature (≤ 5 °C / ≥ 60 °C): foodstandards.gov.au/business/food-safety/keeping-food-at-the-right-temperature
- FSANZ — 2‑hour / 4‑hour rule: foodstandards.gov.au/business/food-safety/2-hour-4-hour-rule
- FSANZ — Thermometers (Standard 3.2.2 cl.22): foodstandards.gov.au/business/food-safety/thermometers
- AS 4674 — design, construction & fit‑out of food premises (overview/guides): Local Council guideline referencing AS 4674
- Gastronorm size background (EN 631 base 1/1 = 530 × 325 mm): Wikipedia overview · manufacturer guide (Moffat/Rieber): Rieber Gastronorm PDF
- Nisbets AU — GN sizes & products: Stainless steel GN · polypropylene GN
- KW internal categories used above (validated): Gastronorm pans · stainless GN · GN accessories · food prep fridges · bain maries
Last updated: . Always check your local council’s practices and your model’s manual for depth limits, load lines and cleaning instructions.
