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Articles
ORGANIC HOP PRODUCTION IN NEW ZEALAND
This is a revised version of an article, written by Tom Inglis et al, originally published in Brewing and Beverage International #1~1996, revised by Tom Inglis 05 November 2001.
By Tom Inglis
In New Zealand, because of its Island situation, isolated from other land masses by ocean, and the unique temperate South Pacific climate, it is possible to grow crops with a minimal use of pesticides. The two major islands of New Zealand, rather practically named North Island and South Island by the European settlers that arrived here more than 150 years ago, have a mild climate and adequate rainfall that is part of a wide range of climatic zones that range from subtropical in the far north, to the cooler climates of the south which is the nearest land mass to Antarctica.
Nestling under the foothills of the Southern Alps at the top of the South Island, surrounding the Tasman Bay, is an area found over 150 years ago by English and German settlers alike to be ideal for hop growing.
The hops currently grown here supply the needs of the brewers in New Zealand whp provide New Zealand's 3.5 million population with beer, but are also exported to America and Canada, several Asian countries, and also to Europe.
Whilst the first hops grown in New Zealand up until the beginning if the 20th Century were almost certainly all organic, the cultivation of hops on a completely organic basis in the modern era, is quite recent and is developing steadily to satisfy a growing demand by the market.
Cultivation of Organic Hops
Since 1990 the Oldham family of Nelson, hop growers for three generations, has developed an organic hop garden together with conventional hop gardens.
The growing conditions for organic hop production are ideal because none of the traditional hop diseases, such as powdery mildew, downy mildew, verticillium wilt, or aphid problems are present in New Zealand.
The organic hops are planted out on land, which is proven residue free and new to hops. Trials are being done with sawdust as mulch for weed control, which is successful, but expensive in labour to apply. Therefore a mixture of grass, oats and clover is grown as a groundcover between the rows of hop plants.
The oats are mulched back into the soil, which is then grassed down. The grass is mown with a tractor mower every five days and the grass cuttings mulch the hops all the time. The oats are just a cover crop to build up the humus levels. The worm count builds up quite considerably and the soil health appears much better under grass in comparison with bare sod between the rows. The grass includes a mixture of clover, which is used for nitrogen fixing and also serves as feed for the sheep grazing in the hop gardens.
The use of sheep in hop gardens is common amongst all the New Zealand hop growers because they help control sucker shoots, which grow from the bottom of the hop vines, and the residue they leave on the soil is very beneficial to the crops.
These grass cultivation methods are also practised by the conventional hop farmers as well as a normal growing practice. All hop farmers use sheep to control sucker regrowth which avoids the use of chemical sprays, but the growing practices differ with the use of fertiliser.
Instead of conventional fertilisers, the organic producers use dried blood and bone, and meal and bone fertilisers. Liquid organic fertilisers are also used.
Rock phosphate and lime are applied with the Lime used to lower the acidity levels of the soil.
Natural dolomite is used as a source of magnesium.
The hop varieties, "New Zealand Hallertau Aroma" and "New Zealand Pacific Gem" are organically cultivated at present.
The organic hops are never sprayed against pests.
Conventionally grown hops may on occasion be sprayed, but only once during the season for two-spotted mite, which is the only pest affecting hops in New Zealand.
However, through extensive research work carried out at the Hort + Research, Hop Research Station funded by the New Zealand Hop Growing Industry, the use of the introduced predator mite Phytoseiulus persimilus, has proved to be a very effective way of controlling the Two Spotted Mite ~ TSM ~ (Tetranychus urticae) that is the only potentially serious pest to the New Zealand hop crop.
So successful is this method of biological control, that most of the hops grown in New Zealand are treated in this way, and spray control of TSM is only used as a last resort in conventional hop crops using a mild miticide.
There is one large international brewer that buys New Zealand hops " without the use of pesticides" and pays a premium for this.
The organic hops are always picked first so that they can be dried in their newly-cleaned hop kiln and are not mixed with their conventionally grown hops.
The first hops from the organic plantings were picked in 1992 and in 1993 production became fully registered by the Biological Producers Council.
Certification of Organic Hops
To reach the required standards for organic production which are set by the Biological Producers Council in New Zealand, broad-spectrum residue tests are carried out on the dried hops. Every year the Biological Producers Council updates the registrations and any deviation from their strict compliance would result in deregistration as an organic producer.
Quality of the Hops
The production yield is reduced under the organic regime, but the alpha acids of the organic hops are not affected and consistently good alpha yields are normal. Because there are no other hop diseases in New Zealand the appearance of the hops is of an extremely high standard and organic hops were actually rated best of a selection of New Zealand hops, when recently evaluated by a major USA brewer.
The two varieties produced organically, "New Zealand Hallertau Aroma" and "New Zealand Pacific Gem", are commercial hop varieties bred at the New Zealand Hop Research Station, located in the heart of the New Zealand hop-growing region. At this time these two New Zealand varieties plus a small amount of "B" Saaz, are the only hops produced organically.
The alpha acid level averages 10.8% for the variety "New Zealand Hallertau Aroma" and 14.1% for "New Zealand Pacific Gem". The hops are sold in bales, vacuum packed Mini Vac Pacs ( vacuum packed cone hops) or made into type 90 pellets in New Zealand and vacuum packed, during the harvest time using the procedure of putting the organic hops through the pellet mill at the start of the season to satisfy the Biological Council's requirements.
Whilst the organic hops may be higher in price than conventionally grown hops, the bittering value of New Zealand organic hops compares favourably to the price of alternate supplies of organic hops, where they can be reliably and regularly obtained, because of the high alpha in the New Zealand organic supply.
In addition New Zealand organic hops also offer attractive oil levels. If you think about it - the small amount of hops used in every brew makes this cost insignificant to the organic brewers and their customers, in comparison to the excellent value.
Outlook
The cultivation of organic hops will most likely always only be for a niche market. The interest in these organic hops to date has been encouraging. New Zealand is an ideal place for the development of this niche market, because hop growers are not faced with pollution levels and pest and disease problems that other hop producing regions have to cope with, and therefore are able to produce organic hops relatively price competitively.
Originally Published in Brewing and Beverage Industry International, No 1/1996, Page 22/23
The Authors
Tom Inglis
Finn Knudsen
David Oldham
Colin Oldham
Winfried RuB
For Further Information Contact:
Doug Donelan
New Zealand Hops Ltd
P.O. Box 3205, Richmond, Nelson, New Zealand
E-mail nzhops@nzhops.co.nz
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