Gastronorm

Gastronorm sized containers and lids stored in a shelf.

Gastronorm originated in Switzerland during the 1960s when various associations gathered and agreed on standard dimensions for movable kitchen inserts and containers such as pans, trays, wire racks as well as other kitchen utensils and equipment.[4] The goals of the standard was to maximize use of the capacity in ovens and fridges by introducing kitchenware in compatible square sizes that left no corners unused. The standard was first formalized 17 November 1964 when different Swiss hotel associations gathered and agreed on the basic metric size of 530 × 325 mm. Despite initial skepticism by chefs claiming that "gastronomy cannot be standardized", the Gastronorm (GN) format has since gained worldwide recognition and is used by a large majority of equipment manufacturers and users of professional kitchens worldwide. On 15 December 1993, the format was adopted by the European Committee for Standardization in the standard EN 631-1: 1993 "Materials and articles in contact with foodstuffs - Catering containers - Dimensions of containers". Today almost all professional European kitchen equipment is built according to the gastronorm standard, enabling flexibility of kitchen operations across Europe when it comes to planning, transfer, delivery, storage and production.

Visual representation of European Gastronorm sizes

The Gastronorm system is based on a fractional sizing, making containers of different sized GN containers interchangeable. For example, a GN 1/1 tray can be substited with two GN 1/2 containers.

Containers usually come in standard depths of 20 mm, 40 mm, 65 mm, 100 mm, 150 mm, 200 mm.[5]

Drain lids and lids with cut-outs such that a serving utensil can be placed into the container are common accessories. They are made in these sizes especially for the catering industry. There are also covers in the same measurements: GN 1/1, GN 1/2, GN 1/3, GN 2/1, GN 1/4, GN 1/6, GN 1/9, GN 2/3.

Other less common sizes are:

Containers can be made of stainless steel, enameled steel, metal covered with a non-stick surface, synthetic or composite materials, earthenware or porcelain. Containers can either have a closed or perforated bottom to facilitate draining or certain specialized types of cooking. Recently, fully compostable Gastronorm trays have also been introduced.[6]

• Electrical kitchen equipment: Gastronorm compatible kitchen equipment such as bain-maries which are designed solely to hold Gastronorm containers are available. Large mobile racks or serving carts are also available for storage and portability.
• Combi steamers: Both commercial and professional combi steamers typically utilize food racks with dimensions corresponding to Gastronorm specifications, most commonly either GN1/1 or GN2/3.
• Plates: A few companies (such as Olympia, Emile Henry, Genware) manufacture ranges of white porcelain dishes in Gastronorm sizes as serveware including decorative lids.
• Serving trays: Gastronorm-sized stainless steel or plastic serving plates are available.
• Bread warmers
• Colanders: Pans with holes so that ingredients can be drained. Can also be used for steaming inside an oven, or to soak the ingredients in an ice bath.
• Dishwashers[7]
• Cutting boards: Gastronorm compatible cutting board are available, for example in the sizes 1/1 and 1/2. For instance as an integral tray that slots in beneath chopping boards, so that food chops can be pushed easily into the tray for either later use or disposal.
• Chafing dish: Food stands are available which accepts Gastronorm sized pans and has an alcohol burner to keep food warm (above 60 °C (140 °F)), for example at a buffet.

• 
  Gastronorm food warmers.
• 
  Gastronorm bain-maries.
• 
  Gastronorm containers used in a canteen.
• 
  Gastronorm sized oven.
• 
  Gastronorm containers used in an ice cream parlor
• 
  Ice cream served from stacked Gastronorm containers with ice between.
• 
  Gastronorm sized baking trays.

Professional kitchen equipment from America are often not built according to Gastronorm, but rather to national non-metric size standards. Both Gastronorm and non-Gastronorm pans are sometimes referred to as "hotel pans", "steam table pans", "service pans" or "counter pans",[8] but such names do not say anything about the underlying standard which the equipment is constructed according to. Similar to Gastronorm, the American hotel pan system is based on a system of fractions, but with measurements which are non-metric and incompatible with Gastronorm. Hence, US pans can also be stacked and fit inside each other, similar to Gastronorm, but the two systems are incompatible.

Depth of American pans are referred to with numbers such as 100, 200, 400, 600 and 800, which roughly indicates their depth in inches when divided by 100. For example, a "200 pan" is about 2​¹⁄₂ inch deep.[8] American hotel pans are also available in different steel gauges, which refers to the thickness of the metal. A higher number means a thinner pan, so a 20 gauge pan is thicker than a 22 gauge. US sized pans are also available with either wide or narrow brims. A narrow brim pan can be placed inside a wide brim pan to make an improvised bain marie. [9]

• Cooking weights and measures
• Sheet pan
• Preferred metric sizes