Moist Indirect Heat

Steaming

Steaming is the cleanest cooking method: no contact with water, no leaching of vitamins and minerals, perfect colour retention. Steam at 100°C cooks via condensation: water vapour releases heat energy when it condenses on the product. Fish done in 8 minutes, vegetables in 3-4 minutes with all their colour preserved. The combi-steamer is the most widely used professional appliance in the Netherlands.

10-15% vitamin C loss when steaming versus 40-50% when boiling in water (WHO Food and Nutrition Paper 77, 2005)

100°C steam temperature at atmospheric pressure (thermodynamic constant)

120°C steam temperature under pressure steaming at 1 bar overpressure (pressure cooker)

8-12 min steaming time for a 150-200 g fish fillet at 100°C (CIA Professional Chef, 2011)

Requirements

Combi-steamer or steaming pot with tight-fitting lid Bamboo steamer basket (Chinese method) Probe thermometer (poultry requires 74°C even when steaming) Ice bath ready for immediate cooling after steaming (vegetables) Timer: steaming does not forgive a single second too long

In brief

[DEFINITION] Steaming

Steaming is a moist cooking method in which food is heated via water vapour, without direct contact with boiling water. When steam (100°C at atmospheric pressure) hits the cooler food, it condenses and in doing so releases substantial heat energy. This is thermodynamically more efficient than boiling in water: steam transfers approximately 2,260 kJ/kg of heat upon condensation, compared with water transferring heat via conduction. The result: faster, more even cooking with minimal nutrient loss.

Nutrient retention: the greatest clinical advantage of steaming. Water-soluble vitamins (B-complex, vitamin C) do not dissolve in steam. Comparison: vitamin C loss when steaming 10-15% versus 40-50% when boiling in water. Mineral (potassium, magnesium) loss when steaming 5-10% versus 20-35% when boiling. (WHO/FAO Food and Nutrition Paper 77, 2005)
Atmospheric steaming (100°C): the standard. Combi-steamer, steaming pot, bamboo steamer basket. Used for fish, vegetables, dumplings, dim sum, rice. No pressure increase, easy to control.
Pressure steaming (pressure cooker, 120°C at 1 bar overpressure): faster due to higher temperature. Pulses, potatoes, tough vegetables in 1/3 of the normal cooking time. Drawback: more vitamin loss than atmospheric steaming and less control over doneness.
Combi-steamer: the professional standard. Combines steam (moist heat) with hot air (dry heat). Mode "steam + convection 180°C" combines the moisture retention of steaming with the browning of baking. The most versatile oven in the professional kitchen. (CIA Professional Chef, 9th edition, Wiley, 2011)

Four steaming techniques

Atmospheric steaming (100°C)

Standard steaming at sea level at 100°C. Steaming pot, combi-steamer or bamboo steamer basket. Fish, vegetables, dim sum, rice. Most widely used method in professional kitchens.

Examples: Salmon, broccoli, dim sum, asparagus, rice

Chinese bamboo steaming (zheng 蒸)

Bamboo steamer basket placed over boiling water in a wok. The bamboo absorbs excess moisture so condensation does not drip back onto the product. Stackable: multiple product categories at the same time.

Examples: Dim sum, dumplings, bao buns, fish, vegetables

Pressure steaming (120°C)

Pressure cooker or professional pressure vessels at 1 bar overpressure: steam temperature rises to 120°C. Pulses (chickpeas, lentils) and tough vegetables in 1/3 of the normal cooking time. Less suitable for delicate products.

Examples: Pulses, tough carrots, artichokes

Combi-steamer (steam + convection)

Professional: steam combined with hot air. Settings: 100% steam (fish, vegetables), 50% steam (bread for crust), 0% steam (crispy baking). Temperature range: 30-260°C. The most versatile oven in professional kitchens.

Examples: Bread, poultry, fish, pastry, vegetables

Sources: CIA Professional Chef (2011); Grace Young, The Breath of a Wok (2004); WHO/FAO Food and Nutrition Paper 77 (2005)

Steaming times and techniques per product

Fish fillet (150-200g)

8-12 minutes at 100°C. Fish is done when the flesh is opaque and flakes easily with a fork. Oversteamed fish: dry and grainy. Always use a timer. Flavour infusion: lemon, ginger, soy sauce in the steam.

Time: 8-12 min Done: flakes apart

Broccoli

4-6 minutes at 100°C for bite-firm (al dente). Transfer immediately to an ice bath for colour retention and to stop the cooking process. Without an ice bath: carryover cooking turns it yellow. Chlorophyll is heat-sensitive; steaming preserves colour better than boiling.

Time: 4-6 min Straight into ice bath

Chicken (thigh)

20-30 min at 100°C for chicken thigh. Core temperature measurement: 74°C mandatory. Steam provides more even cooking than pan-frying. Danger: steam makes the outside appear done while the core is below 74°C. Always measure.

Core temp: 74°C MANDATORY Time: 20-30 min

Dim sum / dumplings

8-12 minutes at 100°C in a bamboo steamer basket. Pre-spray the bamboo steamer with oil to prevent sticking. Perforated parchment paper as a non-stick layer. Steamed, not deep-fried: 60-70% fewer calories.

Time: 8-12 min Bamboo: spray with oil

Eggs (Chinese method)

Beaten egg with broth 1:1, steamed at 80-85°C for 12-15 min. Result: silky smooth, custard-like. Temperature is critical: above 90°C the proteins set too firmly and become porous. Combi-steamer at 85°C setting.

Temp: 80-85°C Time: 12-15 min

Asparagus

White asparagus: 12-18 minutes at 100°C, depending on thickness. Green asparagus: 5-8 minutes. Steaming preserves the characteristic aroma better than boiling: flavour compounds dissolve in cooking water but not in steam.

White: 12-18 min Green: 5-8 min

Core temperature measurement remains mandatory for poultry, even when steaming. Steam reaches 100°C but the core of thick poultry can remain below 74°C without measurement.

Step-by-step method

1

Prepare the steaming equipment

Bring the water in the steaming pot or wok to a boil before adding the fish. Cold-starting steam causes uneven cooking. Check: the water must not touch the steaming rack. Bamboo steamer basket: place over the boiling water for 5 minutes to preheat it empty.

Aroma infusion: add aromatics to the steaming water (ginger slices, lemongrass, star anise). The essential oils travel with the steam and impart subtle aroma to the product, at zero food cost.
2

Pat the fish dry and season

Pat the fish fillet dry. A moist surface dilutes the flavour. Season lightly with salt, white pepper. Place on a plate (not directly on the steamer) to catch the released juices: this is the base for an instant sauce.
3

Place the fish in the steamer

Place the fish in the steamer, lid on. Set the timer. A fillet of 150 g: 8-9 minutes. 200 g: 10-12 minutes. Thicker portions on top for even heat distribution when cooking multiple pieces. Never overcrowd: steam must circulate freely.
4

Doneness check: visual and with a fork

Done: the fish is fully opaque and flakes apart under gentle pressure with a fork. The core is no longer translucent. Too raw: the core is still jelly-like and translucent. Overdone: the flesh is dried out, grainy, and falls apart without pressure.

HACCP: always use a probe thermometer for poultry. Visual assessment is insufficient for the NVWA standard of 74°C.
5

Sauce from the steaming juices

Collect the juices from the plate under the fish. This is a light fish stock with all released flavour compounds. Warm with soy sauce, grated ginger, sesame oil and lime juice for a Chinese finishing sauce. Food cost: EUR 0.15. Flavour value: significant.
6

Serve immediately or cool

Serve steamed fish immediately. For storage: transfer directly to an ice bath after steaming, store at 0-2°C. Maximum 24 hours. Reheat by steaming: 3-4 minutes. Never in the microwave: uneven heating and texture loss.

Chinese finishing technique: pour a mixture of soy sauce and scalding sesame oil over the steamed fish just before service. The hot oil "cooks" the soy sauce on the surface and releases a spectacular aroma cloud.

HACCP: Core temperature and steam unit hygiene

Steaming is not a food safety guarantee: core temperature measurement remains mandatory

A common misconception: steaming at 100°C effectively cooks the surface of food, but with thick poultry or large cuts of meat, the core can remain below 74°C while the outer surface appears done. Core temperature measurement for poultry remains mandatory (NVWA).
Campylobacter jejuni (the most common foodborne infection in the Netherlands) survives if the core of chicken does not reach 74°C. Steaming equipment does not guarantee a specific core temperature: only measurement provides certainty. (RIVM, 2022)
Fish and shellfish when steaming: the EU Regulation 853/2004 freezing requirement also applies to steamed fish served raw or nearly raw. Steaming at 100°C eliminates Anisakis parasites only with sufficient exposure time (core temp above 60°C/1 min).

Source: NVWA — Core temperature guidelines for professional kitchens; RIVM — Campylobacter 2022; EU Regulation 853/2004

Steam unit: water reservoir and condensation hygiene

Water reservoir of steam ovens: a breeding ground for Legionella pneumophila if the water sits between 20-45°C. Drain the reservoir daily and disinfect weekly. Use softened water to prevent limescale buildup. (RIVM Legionella guideline, 2021)
Condensation water in the steam oven drips back into the pan. In dirty steam ovens, this condensate contains bacteria from previous preparations. Daily cleaning of all internal surfaces is mandatory.
Bamboo steamer baskets: cannot be sanitised with bleach (damages bamboo). Clean with hot water and a brush, dry completely before storage. Damp bamboo is a breeding ground for mould. Replace after intensive use (professional standard: 6-12 months).

Source: RIVM — Legionella in water systems (2021); NVWA — Cleaning protocol for combi-steamers; EU Regulation 852/2004 Annex II

Nutrient retention: steaming vs boiling vs roasting

Nutrient	Steaming	Boiling in water	Roasting	Source
Vitamin C	85-90% retained	50-60% retained	60-70% retained	WHO/FAO 2005
Vitamin B1 (thiamine)	90-95% retained	65-75% retained	75-85% retained	WHO/FAO 2005
Potassium	90-95% retained	65-80% retained	85-90% retained	WHO/FAO 2005
Folic acid	80-90% retained	55-65% retained	65-75% retained	WHO/FAO 2005
Beta-carotene	90-95% retained	80-85% retained	85-90% retained	McGee, 2004

Source: WHO/FAO Food and Nutrition Paper 77 (2005) — Effects of food processing on nutrients; Harold McGee, On Food and Cooking (Scribner, 2004)

Food cost: energy-efficient, nutrient retention as a selling point

Energy costs: steaming is more energy-efficient than boiling in water (less water to heat) and considerably more efficient than a conventional oven. A professional combi-steamer in steam mode consumes 4-8 kW, versus a standard baking oven at 8-14 kW. With daily use of 4 hours: savings of EUR 0.80-1.20 per day depending on energy tariff.
Nutritional value as premium positioning: positioning steamed dishes as "preserving vitamins and minerals" on the menu provides a justified basis for a higher price point. Evidence: WHO/FAO Paper 77 (2005) reports 85-90% vitamin C retention when steaming. This is a verifiable claim that the chef can use as a quality argument.
Portion weight after steaming: steaming causes 0-5% weight loss in vegetables (no leaching into water, only slight evaporation). Boiling causes 10-15% weight loss through absorption and extraction. Steaming therefore yields more portion per kg purchased: a direct advantage in food cost calculation.
Steam as a mise en place tool: pre-blanch and cool broccoli, asparagus and fine vegetables in the combi-steamer (3-4 min steam + immediate cooling) for mise en place. This can be done hours before service. For a la carte: 90-second reheat in steam. Labour costs during the rush are drastically reduced.

Frequently asked questions

Why are steamed vegetables more colourful than boiled vegetables?

Chlorophyll (green) and carotenoids (orange, red) are largely fat-soluble and do not dissolve in steam. When boiling in water, water-soluble colour and flavour compounds partially dissolve into the cooking water. Steaming completely prevents this leaching effect. Furthermore, the contact time with heat is shorter when steaming: less thermal degradation of chlorophyll. Immediately cooling in ice water stops the cooking process and fixes the green colour.

Is steamed chicken safe without core temperature measurement?

No. Steam reaches 100°C at the surface but the core of thick poultry can be significantly lower. Campylobacter jejuni (the most common foodborne infection in the Netherlands) requires a 74°C core temperature for elimination. Visual assessment (clear juices, white colour) is insufficient as HACCP evidence. NVWA standard: 74°C core temperature, measured at the thickest point. (RIVM, 2022)

What is the difference between a combi-steamer and a steaming pot?

A steaming pot generates steam via boiling water in the pot, atmospheric (100°C). A combi-steamer is a professional oven that generates steam via an injected water supply and combines it with hot-air circulation. Settings: 100% steam (fish, vegetables), 50% steam + 50% hot air (bread, meat), 0% steam (crispy baking). Temperature range: 30-260°C. The combi-steamer is the most versatile appliance in the professional kitchen. (CIA Professional Chef, 9th edition, 2011)

How do I aromatise steamed fish?

Two methods: (1) aromatics in the steaming water (ginger slices, lemongrass, star anise, coriander seed): essential oils travel with the steam and impart subtle aroma without direct flavour transfer. (2) Aromatics placed directly on the fish (ginger slices, spring onion, chilli pepper) for a more direct flavour. Chinese finishing step: pour scalding sesame oil mixed with soy sauce over the steamed fish just before service. (Grace Young, The Breath of a Wok, Simon & Schuster, 2004)

How long can steamed fish be stored?

Steamed fish: maximum 24 hours at 0-2°C. Fish is the most microbiologically vulnerable animal product: lower water activity and high protein concentration make it an ideal growth medium for bacteria. NVWA standard: store fish at max 2°C. Immediately after steaming: ice bath for rapid cooling. Reheating: steam for 3-4 minutes, never in the microwave (uneven heating).

Which products are most suited to steaming?

Ideal for steaming: (1) fish and shellfish: delicate, quick to cook, high moisture retention, (2) fresh vegetables: maximum colour retention and vitamin preservation, (3) dim sum and dumplings: require precisely 100°C steam, (4) rice: perfect grain cooking without sticking. Less suitable: red meat (no Maillard crust) and products that need to be crispy (steam is the enemy of crispy texture). (CIA Professional Chef, 9th edition, Wiley, 2011)

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Informational disclaimer

The information on this page is intended solely for educational and informational purposes for hospitality professionals. KitchenNmbrs B.V. strives for accuracy and timeliness but cannot guarantee that all information is fully correct, complete or up-to-date at all times. Culinary techniques, scientific insights and food safety guidelines may change.

Professional responsibility

Applying the techniques described requires professional expertise and training. KitchenNmbrs is not liable for damage, injury, illness or loss resulting from the application of information from this website without adequate professional guidance or verification. Every kitchen, every product and every environment is different: always apply your own professional judgement.

Food safety & HACCP

The HACCP guidelines, temperatures and storage advice on this page are based on Codex Alimentarius (WHO/FAO) as the global baseline standard and EU Regulation 852/2004. Local laws and regulations may differ. Always consult your national food safety authority for the applicable standards in your region:

Netherlands: NVWA (nvwa.nl)
Belgium: FAVV (favv-afsca.be)
Germany: BfR (bfr.bund.de)
United Kingdom: FSA (food.gov.uk)
United States: FDA (fda.gov) — FDA Food Code
EU general: EU Regulation (EC) 852/2004 on food hygiene
International: Codex Alimentarius CAC/RCP 1-1969 (revised 2020)

Allergens & dietary information

Allergen information is indicative. When in doubt about allergens in preparations, always contact the supplier or a certified allergological adviser. KitchenNmbrs accepts no liability for allergic reactions or diet-related harm.

Copyright & sources

All sources mentioned (Escoffier, McGee, CIA Professional Chef, etc.) are the property of their respective publishers and authors. KitchenNmbrs cites these works in accordance with fair use for informational purposes. The source attribution at the bottom of each technique page is not a complete bibliography but an indication of primary sources consulted.

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Sources and legal information

WHO/FAO — Food and Nutrition Paper 77: Vitamin and Mineral Requirements in Human Nutrition (2005) — nutrient retention across different cooking methods
Harold McGee — On Food and Cooking (Scribner, 2004) — heat transfer via steam and condensation
CIA (Culinary Institute of America) — The Professional Chef, 9th edition (Wiley, 2011) — combi-steamer and steaming techniques
Grace Young & Alan Richardson — The Breath of a Wok (Simon & Schuster, 2004) — Chinese bamboo steaming
NVWA — Core temperature guidelines and cleaning protocol for steaming equipment (2022)
RIVM — Legionella in water systems: prevention and management (2021)