Juniper is disappearing in Britain

Juniper berries from Juniperus communis are the traditional flavouring for gin-making, being harvested by hand in late summer and collected in traditional wooden trugs in Tuscany & many parts of Eastern Europe. Although some slight fermentation occurs during gathering, too much will impart a turpentine-like note in the beverage. The terpeneless, sesquiterpeneless or re-rectified essential oil prepared from the berries is the ingredient used as a component of gin-making, & cheaper beverages rely almost exclusively on juniperberries to provide the flavour components. More exclusive gin brand names however include a large number of other flavouring components (several being essential oils, such as coriander, orange & cardamon) to give the characteristic brand taste.

The essential oil of juniper berries contains mainly hydrocarbons, especially alpha-pinene, the content of which can vary from 25-55%, some gin manufacturers preferring the alpha-pinene level to be over 50% mark. Small amounts of other monoterpene alcohols such as alpha-terpineol, nerol and geraniol, may also be important for odour quality, and characteristic berry notes might be provided by components such as junionone, juniper camphor and others. Interestingly, the urine of individuals taking juniperberries as a herbal diuretic (the essential oil having a diuretic effect) is said to smell of violets. Commercially juniperberry oil has often been adulterated with limonene and/or juniper twig oils; “berry oils” containing juniper twigs or even branches probably reveal an analysis profile that has increased levels of alpha-cedrene, thujopsene and alpha-cedrol.

A little goes a long way: the use of juniper oil in beverage flavourings is limited to 0.01% in practice due to the gastric irritation effect of juniper oil. Various studies have also revealed that kidney irritation from juniper oil has been ascribed to the terpinen-4-ol content (Schilcher H et al. 1993); & diuretic activity has also been ascribed to terpinen-4-ol which has been said to increase the renal glomerular filtration rate.

A newspaper story by Randall (2007) reports on a study by the plant conservation charity Plantlife, which suggests that the relatively slow-growing juniper, one of only three native conifers, is rapidly dying out in British hillsides. Numbers have shown a 50% decline since the 1970’s - and the species could disappear altogether if nothing is done. Diminishing demand for UK berries (most are now imported, or imported as crude juniperberry liquor), less demand for juniper as firewood and the prickly branches as fencing, and changing land management patterns, are blamed for the situation.

Juniper is becoming yet another example of the ‘use it or lose it’ phenomena amongst economically important plants. Planting juniper species in gardens as ornamentals might help to offset its continuing decline in the wild.

Tony Burfield

References.
Randall D. (2007) “Nations gin tree in need of a tonic” Independent on Sunday 18.02.07 p31. 

Schilcher H et al. (1993) PZ Wissenschaft 138(3-4), 85-91.

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