Cooking kettles: direct or indirect heating — and what size?
A cooking kettle is the machine for everything cooked in quantity and over time: soups, stocks, sauces, goulash, potatoes, pasta. Two decisions drive both the price and the result — direct or indirect heating, and what size. This page explains both with figures from our own range: cooking kettles from five manufacturers, 2,821.79 € to 16,739.28 €, nominal capacities from 50 to 550 litres. All prices are net, plus VAT. If you are looking instead for one machine that fries, braises and boils, see the guide to tilting braising pans.
Direct or indirect heating — the one decision that matters
In a directly heated kettle the heat source sits immediately beneath the kettle base. The heat takes the shortest route into the food: water boils faster, the kettle is simpler to build and cheaper to buy. The price you pay is a hot base — anything that can catch will catch.
In an indirectly heated kettle there is a jacket of water between the heating element and the kettle base. The water is heated, and the steam in the jacket passes the heat evenly to the kettle. The temperature in the jacket has a ceiling, so the base never gets hotter than the steam — which is why practically nothing burns on.
| Directly heated | Indirectly heated | |
|---|---|---|
| Heat path | heating directly under the kettle base | via a water and steam jacket |
| Strength | reaches the boil faster, cheaper | even heat, practically nothing burns on |
| Weakness | hot base, risk of catching | longer heat-up, the jacket needs care |
| Suits | water, pasta, potatoes, boiled sausage | sauces, milk-based dishes, stocks, soups with garnish |
| Premium at the same size | — | 168.20 € (Maxima 60 l) to 1,260.00 € (Virtus 50 l gas) |
Neither premium is an estimate; both are the difference between two machines of the same series and size in our range. The Maxima Heavy Duty 60 l direct costs 2,821.79 €, the identical indirect model 2,989.99 €. At Virtus, however, 50 l gas direct (3,881.50 €) and 50 l gas indirect (5,141.50 €) are 1,260.00 € apart. The premium depends heavily on the series — a blanket percentage would mislead you.
Twenty-six of our kettles state indirect heating in the product title and twelve state direct heating. For the rest, the design is not in the title but in the manufacturer's type code; at Bartscher, E means electric and G means gas, and the heating method is listed in the technical data on the product page.
What size? Nominal volume is not usable volume
Kettles are sold by nominal volume — nobody fills them to the rim. To estimate how much food comes out, work with roughly four fifths of the height and a normal portion size. The table below is our own rough calculation, not a manufacturer's figure: 0.3 l per portion of soup, 0.25 l per portion of sauce or stew garnish.
| Nominal volume | usable (approx. 80 %) | Soup at 0.3 l | Typical operation |
|---|---|---|---|
| 50–60 l | 40–48 l | around 130–160 portions | restaurant, hotel kitchen, snack bar |
| 100–150 l | 80–120 l | around 265–400 portions | staff canteen, school catering |
| 250–325 l | 200–260 l | around 665–865 portions | large-scale kitchen, catering |
| 420–550 l | 335–440 l | around 1,115–1,465 portions | central kitchen, food production |
Our range covers 50, 55, 60, 100, 113, 120, 135, 145, 150, 160, 220, 250, 260, 265, 325, 342, 420, 480 and 550 litres. The rule of thumb when choosing: one size up beats one size short. A half-full kettle cooks perfectly well, whereas one that is too small forces a second run — and that costs a full heat-up cycle.
On footprint: the Bartscher Series 700 with 55 l measures 800 × 700 × 850 mm and weighs 95 kg; the Bartscher E480L with 480 l comes in at 1,150 × 1,300 × 1,030 mm and 300 kg. From roughly 300 litres upwards the kettle becomes a fitted appliance that belongs in the kitchen plan — supply line, drain and turning space for the transport trolley included.
Gas or electric
Twenty-one of our kettles have gas in the title and seventeen electric; for the remainder it is in the type code. The decision is rarely a matter of taste — it follows whatever the site already has.
Electric needs three-phase power in this class of machine. The Bartscher Series 700 with 55 l has a connected load of 9 kW at 400 V — not a domestic socket but a fixed connection made by a qualified electrician. In exchange there is no flue and no gas inspection.
Gas is often cheaper to buy and heats hard, but it needs the gas installation, the inspection and the right space under the hood. How to size the extraction is covered in the guide to extraction hoods.
There is one exception at the small end. If you only cook modest quantities of sauce, cream or compote under constant stirring, you do not need a kettle with a fixed connection. The Frucosol BC100 cooking machine with stirrer runs on 230 V for 793.10 €, measures 540 × 390 × 240 mm and weighs 10.5 kg — a countertop machine rather than a kettle, but often exactly right for patisserie and small batches.
What makes the difference in daily use
Drain. A kettle from roughly 100 litres upwards is drained, not ladled out. The drain tap sits low at the front; underneath it belongs a container on castors or a floor drain. Soup with garnish needs the larger bore — Virtus offers drain funnels in three sizes to match the kettle.
Level monitoring. In an indirectly heated kettle the jacket must not boil dry. Better machines watch this themselves: the Bartscher 700 has automatic level monitoring, and the E480L adds pressure monitoring with a safety valve calibrated to 0.5 bar.
Condensate. Indirect kettles collect condensate in the jacket. Virtus offers a kit that evaporates the condensate automatically for 388.50 €. That money buys away a manual job that would otherwise come round regularly.
Cleaning. Rinse the kettle out hot, while residue has not yet dried on. Stainless steel 18/10 takes that; what it does not take is covered in our note on stainless steel care.
What a cooking kettle costs
| Machine | Volume | Heating | Price, net |
|---|---|---|---|
| Frucosol BC100, countertop with stirrer | — | electric 230 V | 793.10 € |
| Maxima Heavy Duty, gas | 60 l | direct | 2,821.79 € |
| Maxima Heavy Duty, gas | 60 l | indirect | 2,989.99 € |
| Virtus, gas | 50 l | direct | 3,881.50 € |
| Virtus, electric | 60 l | direct | 4,028.50 € |
| Combisteel Base 700, electric | 60 l | indirect | 4,080.70 € |
| Virtus, electric | 50 l | indirect | 4,868.50 € |
| Bartscher Series 700, electric 9 kW | 55 l | — | 6,371.28 € |
| Maxima, gas | 325 l | indirect | 7,786.59 € |
| Bartscher E480L, electric | 480 l | indirect | 16,739.28 € |
Entry into a full-size kettle starts with us at 2,821.79 €. Above that it is not the equipment that drives the price but the volume: between 60 and 480 litres there is a factor of six.
Cooking kettles in our range
- Frucosol BC100 cooking machine with stirrer, 793.10 €, 230 V, countertop machine for small batches
- Maxima Heavy Duty 60 l, direct, gas, 2,821.79 €, our lowest-priced full-size kettle
- Maxima Heavy Duty 60 l, indirect, gas, 2,989.99 €, 168.20 € more than the direct model
- Virtus 50 l gas, direct, 3,881.50 €
- Virtus 60 l electric, direct, 4,028.50 €, 400 V
- Combisteel Base 700, 60 l electric, indirect, 4,080.70 €
- Virtus 50 l electric, indirect, 4,868.50 €
- Bartscher Series 700, 55 l, 6,371.28 €, 9 kW, automatic level monitoring
- Maxima 325 l, indirect, gas, 7,786.59 €, large-kitchen format
- Bartscher E480L, 480 l, 16,739.28 €, with pressure monitoring
- Virtus condensate evaporation kit, 388.50 €, for indirect kettles
Frequently asked questions
Direct or indirect, if I cook both kinds of dish?
Indirect. Water and potatoes work in an indirect kettle too, only a little more slowly. The reverse does not hold: a milk-based sauce in a directly heated kettle needs constant stirring or it catches. If one machine has to cover both, buy the indirect one.
How much electricity or gas does a kettle use?
That depends on size and design; a blanket figure would be guesswork. What our data does show: the Bartscher Series 700 with 55 l has a connected load of 9 kW at 400 V. That is the peak while heating up, not continuous consumption — once it reaches temperature the machine throttles back. The general levers are covered in our note on energy efficiency in large-scale kitchens.
Do I need a tilting kettle?
Only if you remove thick or chunky food. Liquids run out through the drain tap, and nothing needs to tilt for that. Tilting kettles cost more and need clear space in front. If your main job is searing and braising, a tilting braising pan serves you better anyway.
Will a cooking kettle fit under an existing hood?
Check height and extraction capacity before you order. These machines are 850 to 1,030 mm tall, the open lid adds to that, and a gas kettle sends combustion air up as well. If in doubt, send us the dimensions of your hood and we will work it through.
Is a second-hand cooking kettle worth it?
On an indirectly heated kettle the jacket is the part you cannot judge from the outside — corrosion in there is expensive. Anyone buying used should see a pressure test and the documentation. The general trade-off is covered in our new or used guide.
Unsure about size and heating?
Tell us what you cook in it and for how many guests — the size usually follows from that. Add what the site already has: gas, 400 V or both.
For machines from roughly 300 litres upwards we look at the installation site first: supply line, drain and access all have a say.
To the category: Cooking kettles
Related guides
- Tilting braising pan: searing, braising and boiling in one machine
- Mulled wine service: pot, dispenser or tap system
- Extraction hoods: what belongs above the kettle
- Energy efficiency in large-scale kitchens: where consumption actually arises
Last updated on 3 November 2026.