Ever queried why disused hop kilns dot the Nelson region? Despite my ancestors having toiled in the hop fields, I have often wondered. It appears an innovative kiwi attitude to the cultivation of superior crop cultivars contributed significantly.
First planted in the Nelson region over 150 years ago by the early settlers, the crop flourished in our ideal climate at the required latitude of between 35-45 degrees, and it soon became the only centre of production in New Zealand, and arguably the best in the southern hemisphere. In the 1920's a Californian variety, 'Late Cluster' was introduced that produced much greater yields, but by the late 1940's this widely planted variety became severely infected by the fungal root rotting disease Phytophthora. A hop research station funded by the New Zealand Brewers Association developed three resistant strains by 1960. By then the worlds breweries were beginning to demand seedless hops for an increasing popularity in lager beers.
This was not a huge concern to local growers who at the time were supplying the country's then only two main breweries. The europeans began removing the male plants from the dioecious crop while at the New Zealand Hop Research Station, the late Dr R.H. J. Roborgh, followed a breeding programme to combine both the aroma and alpha yield to produce the worlds first triploid hop plants. Plants with an odd number of chromosomes found to produce virtually sterile seedless fruit while retaining the flavour and composition of the originals. He more than doubled the important alpha-acid content, which meant the New Zealand brewers only needed half the amount of hops. Oops.
Today the situation is entirely different, the industry has trebled in size with 90% of our annual crop exported. Twenty-five growers cover 380 hectares and produce around 850 tonnes of processed hop pellets annually, globally representing less than 1% of the world's supply.
Formed in 1939, the New Zealand Hop Marketing Board has a good record of co-ordinating the marketing of hops and hop products for the successful growers that remain and in 1993, working alongside the wholly grower owned processing facility NZ Hop Products Ltd, they developed a hop pelletising process. The reduction in shipping costs has helped secure contracts with numerous brewers worldwide including Guiness, Heineken and Coors. The next step is the extraction of the resins to enable an even more efficient export of the bittering alpha-acid agents, as a canned product that is also much easier to administer to the brewing process.
The New Zealand hop industry has recently formed Extract Solutions Limited, a joint venture fluid extraction plant near the Richmond hop plant, which will provide the ability to extract hops for those customers interested in this product. It is intended to be in full production in May 2002 and will be the only supercritical extraction plant of this commercial size in the southern hemisphere. The plant will not only extract hops, but also nutraceutical products (natural products with pharmaceutical like properties).
A hugely expensive plant using very advanced technology, it will have three 850 litres 'vessels', each capable of extraction at 500 bar pressure, requiring engineering of the highest integrity. The plant throughput will be 2-4 tonnes per day, depending on the product.
