App-supported alcoholometry


Accurate determination of the alcohol content of spirits, as well as of intermediate products, is extremely important for distilleries for several reasons. On the one hand, the alcohol content must be indicated very precisely on the label of spirits. Secondly, it is decisive for the calculation of the alcohol tax. Moreover, the alcohol tax represents a certain part of the cost of goods, so the alcohol content is also an economic component. With Alculate's range of functions, you can accompany the entire workflow with precise calculations. In the following, we will briefly talk about the determination of the physical quantities.


Aräometry basically involves determining the density of a liquid. Accordingly, if the density is known for various concentrations, it is possible to determine the concentration of the solution from it. For most azeotropic mixtures (acids, alcohols, sugars, etc.), this relationship between density and concentration is described mathematically.

Before there were electronic density meters, the measurements were made with hydrometers. With alcoholometers, the alcohol concentration is displayed in % vol at 20 °C. Relatively extensive tables were then used to correct the measurement result with respect to temperature. In most cases, the measurement will not be taken exactly at 20 °C, so the density error must be compensated. For example, at 13.4 °C a solution will have a different density than at 20 °C. So this effect must be taken into account.

When determining by means of a hydrometer, other effects must be taken into account. For example, the glass of the hydrometer is also subject to density fluctuations. The surface tension produces a small error and must be corrected accordingly. Furthermore, densities always refer to the vacuum, but since the buoyancy of the air acts on the alcohol to be weighed, this effect must also be corrected. The air buoyancy error remains even when electronic hydrometers are used.

These (mostly bending oscillators) have increasingly found their way into small distilleries in recent years. They are now even available as hand-held devices and hardly exceed a purchase price of €3000.00. The advantage of these devices lies in their speed and accuracy, and they already carry out temperature correction during measurement.

Nominal alcohol content

The actual proportion of alcohol in lA (liters of pure alcohol), can be determined either by determining the weight or the volume of the distillate. In the case of large containers, only the volume measurement will generally come into question. In this case, the temperature of the container must also be measured, because a temperature-related correction must also be made here. When determining by means of weight, the air buoyancy effect must be taken into account, as already mentioned at the beginning. Although it appears to be an error with a small influence, it cannot be neglected.

Offset calculation

Offset calculation is another sensitive step. In particular, the effect of contraction comes into play here. The mixing of liquids of different densities is always accompanied by this effect. Simply put, when blending 50 liters of 100% distillate and 50 liters of water, the result would precisely not be 100 liters, but only 98.5 liters, for example. This means that the alcohol content is always slightly higher than the expected value. This contraction is of course taken into account with Alculate, and blending crosses and contraction tables are a thing of the past. With the required accuracy, these methods can only be described as a rough estimate.

The blend calculation is possible in two directions. The downsizing (which is generally meant by offsetting or blending) or the upsizing. Which is a rather rare case. In this case, the concentration of the distillate is increased. This may be necessary if, for example, more alcohol has been lost through storage than was initially assumed. A blending error is also a scenario where fortification is required.

In Alculate, they also have the "Target value search" function, which can be used to select a quantitatively fixed result. For example, if you want to produce exactly 100 l of vodka from a distillate, you can use the target value search to determine the exact amount of water and distillate.


Especially from a tax point of view (tax value in the business sense or also from the point of view of supervisory authorities), the recording of work or calculation steps is significant. Apart from operational records, Alculate supports you in recording. You can record all performed measurements (e.g. in the context of an inventory) accordingly and export them later for further processing.