Distillation Parameters and their Influences on Extraction Dynamics in Gin Distillation

A comparison of extracts of gin botanicals with known origin, family and their state (plant part, dried/fresh, whole/kibbled/powder) is investigated. The distillations are conducted on an extraction funnel with a vapour chamber, 1l glassware laboratory setup with temperature-controlled heating mantle. A correlation of extraction dynamics by changing solute amount and solvent concentrations in a vapour extraction distillation is investigated. These conditions have been altered in initial ethanol concentration of the charge and the weight of botanicals. Additionally, two different bulk charges are tested. The single botanical distillations are used to investigate how flavour and aroma compounds are effectively extracted and ultimately how they dier from one botanical to another. This experiment aims to investigate whether there is an optimum mix of conditions to extract the highest levels of certain compounds in gin distillation. The experiment design is a 32- factorial design with two initial base conditions (charge levels) resulting in 18 individual distillations. The botanical chosen is Juniperus communis L., being the prime botanical in gin. Comparing the list of flavour compounds identified in gin, with the flavour compounds identified in the essential oil of juniper berries the following chemical compounds have been chosen as markers: α-pinene,α-phellandrene,β-pinene,β-phellandrene, Myrcene, DL-Limonene, γ-terpinene, α-cubebene, caryophyllene, γ-elemene. It is expected to see different concentrations in the nal distillate, which are compared to each condition. The quantification is carried out with Gas chromatography/ mass spectrometry. Additionally, the aroma intensity is evaluated by a tasting panel, and conclusions can be drawn on the concentration and the odour threshold from the above mentioned compounds. Jan Hodel, PHD Student International Centre for Brewing and Distilling / Heriot-Watt University