Hops give beer its distinctive bitterness and aroma. They have been added to beer for centuries as a flavouring and a preservative.
But in the UK, hop-growing has been declining. The main growing areas, the counties of Kent and Hereford & Worcester, have both seen a steadily diminishing acreage given to hops.
The National Hop Association of England (NHA) points out that there are less than 8,000 acres of hops left in this country. In Germany, which takes a lot of pride in its beer tradition, hops are grown on about 50,000 acres.
The NHA, formed in 1987, is now fighting a campaign to stem this trend by promoting the hop. The latest salvo fired was at the English Ale Awards, held last month at the White Horse in Parsons Green, London.
A number of small breweries entered specially brewed beers for judging in an NHA-organised competition. At the awards ceremony, beer writer Roger Protz extolled the virtues of hops, describing them as "the grapes of beer".
Beers were put into categories according to which hops they used. The winning beer brewed using Progress hops was Thunderstorm, from the Wiltshire brewery Hop Back.
This rapidly expanding operation was set up by John Gilbert and his wife Julie in 1987, with a tiny brewing plant based in the back of the Wyndham Arms in Salisbury. Now the business has equipment of 10 times the capacity and is about to buy its fifth pub.
My own favourite from the brewery's adventurous range is Summer Lightning, which has been around for six years.
It is brewed using Challenger hops to give it bitterness, and Goldings hops to give the beer its aroma.
"We've all got a very bitter palate," says head brewer Richard Lyall, to explain the brewery's reputation for producing distinctively bitter beers.
The latest piece of kit to be installed in the Hop Back brewery - now based outside Salisbury on an industrial estate at Downton - is a bottling machine.
The first fruit of this is a bottle-conditioned version of Summer Lightning. For the time being this will only be sold through the off-licence chain Oddbins, but if it proves a success, Lyall says the availability could be widened.
Meanwhile, pubs and bar operators can stock Summer Lightning in its cask form.
Be warned, though, this pale beer drinks easily but packs a powerful punch.
Telephone Grieg Futcher on 01725 510986.