Calculates from the indicated temperature of the thermometer in ice water and with a water distillation, how much and in which direction the thermometer measures inaccurately.
This "thermometer error" consists of two numbers separated by a space and then corresponds to a two-point calibration if the temperature was measured in ice water and in vapor.
Alternatively, the thermometer error consists of only one number if only one of the two was done.
The thermometer error can be entered into some of our calculators and will then be included in the calculation.
Measuring ice water and water vapor gives much more accurate results than doing just one of the two, since a thermometer at 0°C will usually measure a different error than at 100°C.
If you measure in °F, the thermometer error code is still calculated with respect to °C, since only this can be used in the other calculators.
Water vapor measurement:
It is best to measure the steam temperature directly with the still.
Because then any inaccuracies such as a poor installation position of the thermometer are also taken into account.
On the other hand, the worse the installation position is, the more likely the determined thermometer error is then only valid for measurements during distillation or only with exactly this still, and rather not for other occasions, such as the temperature correction when diluting alcohol.
There is an interesting discussion about the installation position of thermometers here in German:
Thermometer / Position/ Eintauchtiefe
Be sure to enter the
local atmospheric pressure.
Many current smartphones have a very accurate atmospheric pressure sensor.
However, only a few apps show both, the mean sea-level pressure (MSLP) and also the local atmospheric pressure.
You should look for such an app.
You may have to try out several.
Atmospheric pressure data from weather services is almost always mean sea-level pressure (MSLP), since only this is meaningful for the weather situation.
If you only get the mean sea-level pressure (MSLP) or you only know the elevation, you can use our tool
Elevation - Atmospheric Pressure to calculate the local atmospheric pressure.
Ice water measurement:
There are many tutorials on ice water measurement on the internet.
If you want to have it accurate to 0.1°C, you should take some things really seriously:
- The ice must be finely crushed.
- Pay attention to the ratio of ice to water described in the instructions.
- As a container you need a thermos flask.
- Take distilled or demineralized water.
Soft tap water is also fine.
- The ice water must first be prepared in the sealed thermos flask for 30 minutes, so that the water reaches 0°C.
In the meantime, shake it from time to time.
- The thermometer then needs a few minutes in the ice water until the temperature no longer changes.
- The sensor should not touch the ice but the water.
Since ice is lighter than water, i.e. it floats on top, there is an area without ice pieces at the bottom of the thermos flask.
If you want to use a value for the two-point calibration besides the boiling point of water, which is not as low as the freezing point of water, you can use the boiling point of preferably highly concentrated ethanol.
We also have calculation options for this:
Thermometer Error with Ethanol Distillation
Especially if the installation of the thermometer in the still is not ideal, for example the thermometer is not immersed far enough, this thermometer error determination is better than one with ice water, because it compensates the installation error to a large extent.
However, this thermometer error is then not suitable for measurements outside the still.
It can therefore be useful in such cases to determine several thermometer errors for one thermometer.