Heat-up time calculator
Much of a run's waiting happens before anything comes out of the still. Plan it: how long your boiler takes to reach the boil - or any other temperature - from its volume, strength and heating power, and how much energy that uses.
The background is in Heating element power.
How to use it
- Enter the charge. The volume in the boiler and its strength: around 8–12% for a wash, about 30–40% for a spirit-run charge.
- Enter the starting temperature. A wash that has stood in a cold garage starts well below room temperature.
- Enter the power. The element's real power, which depends on your mains voltage - the heating element guide shows how to work it out.
- Set the losses. About 90% of the heat reaches the liquid in a well-insulated boiler, 75–85% in a bare one, less in a cold or draughty room.
- Choose the target. Untick “Heat until it starts to boil” to heat to a set temperature instead, for example for a mash.
How it works
The energy needed is the weight of the charge, times its specific heat, times the rise in temperature. A wash weighs a little less than water and holds a little more heat for its weight; a strong spirit charge weighs less again and needs noticeably less energy. The calculator allows for both, using the strength you enter.
It also works out the temperature at which the charge begins to boil - lower for stronger charges - and stops there. Dividing the energy by the power that actually reaches the liquid gives the time. The kWh figure is the electricity drawn from the mains, losses included; multiply it by your tariff to find the cost.
Worked examples
25 L of 10% wash starting at 20 °C, on a 3,000 W element in an insulated boiler, reaches the boil at about 92.8 °C in 46 minutes, using 2.32 kWh. In a bare boiler losing a quarter of its heat it takes 56 minutes.
A larger still - 100 L from 15 °C on 5,500 W - takes about 1 h 48 min.
Where Stilligent fits
Stilligent measures rather than estimates. Its Smart Watchdog reports the element's actual power, the mains voltage and the energy used in every run - so the cost of a run is simply the kWh it records, times your tariff. The element's true output is measured at the start of each run.
It heats at full power to begin with, then holds the power you set, in kilowatts, as the mains voltage rises and falls, so heat-up and run times are repeatable from one day to the next. Temperature charts and power readings are kept for every run, and the whole run can be exported as a CSV file.
Questions
Why does my still take longer than the calculator says?
Most often the element is giving less than its label says, because the mains voltage is lower than its rating, or more heat is escaping than allowed for. A lid, insulation and a sheltered spot all help.
Should I heat at full power?
During the heat-up, yes. Turn the power down well before the boil, so the still comes up gently and doesn't surge or foam over - and stay with it from then on.
Is a bigger element always better?
It shortens the heat-up, but a column has a limit to how much vapour it can handle. The reflux column calculator shows the power that suits yours.
How much does a run cost?
Multiply the kWh by your electricity price for the heat-up. The run itself uses about the power you run at, times the hours. Stilligent records the energy each run actually uses, so the cost of a whole run is one multiplication away.
Does a mash with grain heat differently?
The solids heat much like the liquid, but they can settle and scorch on a bare element. Strain them out, or stir and use gentle heat.
More calculators for distilling
- Ethanol boiling point and vapour strength calculatorWhat a still temperature tells you about the liquid and the vapour above it.
- Reflux column calculatorColumn diameter, power, packing height, output and cooling water.
- Spirit-run charge calculatorLow wines, feints and water, mixed to the strength you want in the boiler.
Free to use, in metric or US units; your settings are remembered on this device. All results are estimates for planning: check strengths with a hydrometer or alcoholmeter. Distil only where it is legal to do so, and never leave a running still unattended.
Underlined terms are explained in the glossary - tap one for a quick definition.