This month’s Nature Notes were inspired by a trip to our local pub, The Hermit in Burley Woodhead. The pub has been rejuvenated under new owners and is once again a popular place for a cool drink on a hot day. Rather appropriately, given its association with the brewing industry, they are growing Hops (Humulus lupulus) up the terrace where I am now sitting enjoying a drink.
Hops are vigorous climbers, often seen growing to the top of hedgerow trees. Always twining in a clockwise direction, it can shoot up to nine metres in length, and can completely cover other plants, perhaps explaining its specific name - lupulus, meaning ‘little wolf’. The English name Hop comes from the Anglo-Saxon hoppan meaning to climb.
The Hop plant is dioecious, just like Holly and Yew it has separate male and female plants. The male flowers are inconspicuous loose bunches. The female flowers are leafy cone-like catkins, called strobiles. These are initially also small and inconspicuous. As they develop, the yellow-green leaf-like bracts increase in size to produce the hops themselves which are harvested in September, not forgetting that they will only be found on female plants just like Holly and Yew berries.
Hops were cultivated widely in the south-east of England, grown up frameworks of wooden poles, usually made from Sweet Chestnut, and wire. Harvesting the crop required a large force of seasonal workers until mechanization was adopted in the late 1950's. Many families from the East End of London travelled down to Kent for a working holiday in September. Now, sadly, more and more hops going into British beer are grown overseas.
Although Hop is a native UK plant found in hedgerows and along woodland edges, hops have only been grown commercially in southern Britain since the 15th century. Prior to this beer was flavoured with any number of herbs: Meadowsweet, Yarrow, Dandelion, Nettles, and Agrimony to name just a few. Initially the addition of hops was not used for its bitter taste to counteract the sweetness of the malt, but because of its antibacterial effect giving the beer a longer cellar life, stopping it turning sour. In the beginning there was a great resistance to their use. Hence the use of the two terms - ale which was made without hops, whereas beer was made with them, although they are now used interchangeably.
What is causing the bitter flavouring and antibacterial effect? Back to the Hop plant at The Hermit. I pick a green hop cone and gently pull it apart, at the base of the leaf-like bracts are yellow grains. This is not pollen, don’t forget this a female plant, but lupulin glands. These produce essential oils and resins which give beer its bitter taste and at the same time producing the antiseptic effect.
To preserve these volatile oils, the harvested hops must be taken quickly to the kilns or oast houses, where they are gently dried before being taken to the brewery.
On which subject, enough of the botanical science, I think it is time for another pint of ale.