Patent ID: 8106361

Claim:
A method for determining a content of ethanol and of other monovalent alcohol in liquids, which comprises the steps of: obtaining a liquid including at least water, ethanol or another alcohol, and at least one additional substance selected from the group consisting of sugars and fruit acids; performing one of providing a liquid in an analysis cell and flowing the liquid through a throughflow cell; irradiating the liquid via at least one light source formed with an LED, the light source emitting infrared (IR) radiation with a wavelength in a range from 1000 to 1500 nm by the further step of: irradiating the liquid one of temporally successively and practically simultaneously with a first IR radiation with a first wavelength λ1, at which an absorption coefficient of the ethanol or the other monovalent alcohol, Epsalkλ1, and an absorption coefficient of water, Epswλ1, are at least substantially identical to each other and with at least a second IR radiation with a second wavelength λ2, at which the absorption coefficient of the ethanol or the other monovalent alcohol, Epsalkλ2, and the absorption coefficient of the water, Epswλ2, are different from each other; measuring IR light absorption at least two different wavelengths of the infrared radiation resulting in measurement values; converting the measurement values to data reflecting at least an alcohol content of the liquid; forwarding in each case at least two real absorption values, which are determined currently by use of at least one IR detector, to a calculating and display unit for one of calculating and displaying and printing out of at least the alcohol content of the liquid; irradiating the liquid to be examined with a third IR radiation with a third wavelength λ3, at which the absorption coefficient of the ethanol or the other monovalent alcohol, Epsalkλ3, is clearly different from the absorption coefficient of the water, Epswλ3; performing the step of irradiating the liquid to be examined with the third IR radiation for increasing an accuracy of a result with regard to at least one of a content of the ethanol or the other monovalent alcohol and for at least one of compensation of turbidities in the liquid and for a determination of a content in the liquid of other components than ethanol or the other monovalent alcohol, the other components being selected from the group consisting of sugar, extracts, dyes, fruit acids and dyes; using the infrared radiation from an IR radiation source which optionally emits simultaneously two or three different wavelengths λ1, λ2 and λ3; and using broad-band IR radiation from an IR radiation source from a LED-IR light source, whose peaks present a width at half value in a range from 50 to 100 nm.