Today in 1967, US Patent 3332748 A was issued, an invention of Jack Albert Spicer and Max William Betts, for their “Extraction of Hop Bitters from Beer With Iso-Octane Using Synchronized Pulses in a Helical Coil.” There’s no Abstract, although in the description it includes this summary:

This invention relates to the extraction of chemical substances from liquid mixtures and in particular to the extraction of such substances from complex mixtures for purposes of analysis.

In the analysis of a complex mixture, it may be desired to separate one or more constituents of the mixture, by liquid/liquid extraction methods, in order to obtain a relatively simple solution, for example for spectrographic analysis. Thus, for example, it has been proposed to extract hop bitter substances from brewers wort or beer by liquid/liquid extraction with iso-octane, whereupon the solution of the hop bitter substances may be analyzed by ultra-violet spectrographic analysis. The present invention provides an extraction process suitable for use in the separation of desired compounds from such mixtures.

According to the invention, a process for the extraction of a chemical substance from a liquid mixture comprises feeding the liquid mixture and a solvent for the desired chemical substance in synchronized pulses through a horizontally disposed coiled tube, and separating the residual liquid mixture from the solution of the desired chemical substance in the solvent. Preferably the coiled tube is helically coiled.