Water Heating

BrewCo Brew Tools

Use this free water heating calculator to estimate how long it'll take to bring your brewing water up to temperature — handy for planning your brew day timings.

How to use it

  1. Enter your water volume and starting (tap) temperature.
  2. Enter your target temperature.
  3. Enter your heating element or burner's power in Watts (a typical urn is 2000–3000W).
  4. Read off the estimated heating time in minutes.
Typical urn/element: 2000–3000W. Gas burners vary — 3000W is a fair estimate.
— mins
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Why does this matter for brew day?

Knowing roughly how long your strike and sparge water will take to heat helps you plan your whole brew day — especially if you're heating water for multiple stages (strike water, sparge water, and cleaning water). This calculator assumes no heat loss to the surroundings, so actual times will run a little longer, particularly with an uninsulated kettle in a cold garage.

More free home brew calculators

Browse our range of brewing urns and burners at BrewCo UK, Sowerby Bridge.

How long will my brewing water take to heat?

What it does: this calculator estimates how long your boiler, urn or burner will take to bring a volume of water from its starting temperature to your target, so you can plan your brew day.

How to use it: enter the volume of water, the temperature it starts at (cold tap water is often 10–15°C), the temperature you need and the power of your heater in watts. Most electric urns and boilers are 2,000–3,000W.

The formula in plain words: it takes about 4,186 joules to warm one litre of water by 1°C. Multiply that by the volume and the temperature rise to get the energy needed, then divide by your heater's power (joules per second) to get the time.

Worked example: 25 litres from 15°C to 75°C with a 3,000W element needs about 6.3 million joules, which takes about 35 minutes. Bringing 30 litres from 15°C to boiling with a 2,500W element takes more than an hour.

The calculator assumes no heat is lost, so real times will be longer, especially with an uninsulated kettle in a cold garage. A lid helps a lot. Work out the temperature you actually need with the strike temperature calculator.

Frequently Asked Questions
Why does it take longer than the calculator says?
Heat escapes from the sides and top of the vessel as it warms. The bigger the temperature rise and the colder the room, the more you lose. Use a lid and insulate the vessel if you can.
How do I find my heater's power?
It is usually printed on the label or in the manual, in watts (W) or kilowatts (kW). 1kW is 1,000W.
Can I use it for gas burners?
Yes, as a rough guide. Gas burners vary a lot, and much of the heat goes past the pot, so 3,000W is a reasonable starting figure for a typical burner.