Mt Difficulty Wines Ltd is an accredited member of the Sustainable Winegrowing initiative (SWNZ).
The Initiative was launched by the New Zealand winegrowing industry in the mid 1990's to provide guidance on sustainable management of vineyards and wineries. It stemmed from the recognition that, as New Zealand's natural land and water resources were limited, so too were the natural resources of the winegrowing industry. These resources require not only protection, but enhancement, if the New Zealand winegrowing industry is to flourish long term.
The Sustainable Winegrowing initiative now forms a significant part of New Zealand Wine's international marketing message. The Initiative covers a wide range of environmental concerns, from conservation to social responsibility.
Mt Difficulty Wines has chosen to use the SWNZ framework for sustainability as a foundation on which to build, targeting a higher level of sustainability than is required by the initiative. Our state-of-the-art waste water treatment plant and the living roof on our new barrel hall are both testament to our intention to do all we can to protect and enhance our environment, both now and in the future.
The Mt Difficulty Winery was designed as a low energy input winery. The entire winery is housed in insulated buildings, and our new barrel hall is sunk below ground level to enable even more stable and lower energy inputs. Any tanks which are housed outside are also insulated. Our policy has always been to build in energy efficiency for the long term and to seek out innovative technology to keep us ahead of current practice.
For example in the new barrel hall we have installed a low energy ultrasonic humidification system combined with an external air heat reclaim system to allow us to utilise ambient heating and cooling wherever possible. The generally recognised 'gold standard' for humidification has been by steam generation; our technologically advanced system uses about 1% of the energy needed for the equivalent steam system.
The semi-extensive green roof is actually also a warm roof, having R4 insulation underneath the growing medium to keep all of our heat in, and the heat of the day out! The green roof also helps to reduce storm water runoff and is a disposal area for our winery wastewater treatment plant.
With the same policy we have rejected the cheap and simple solution of using LPG for tank heating and hot water supply. At a much greater capital cost we have installed a wood-chip fired boiler which utilises waste from local sawmills; a renewable, non-fossil, local and otherwise wasted resource. A bonus has been that the hot wash-down water this system supplies has enabled us to do much more cleaning with water only and has slashed our need for cleaning chemicals.
Likewise with the wastewater we have exceeded current requirements and installed a tertiary treatment system which combines winery and septic streams into a Membrane Bioreactor to produce clear sterile water that can be passed directly into the irrigation system.
Our plans for the future include using parts of our existing irrigation infrastructure to run a micro-hydro generator so that we can become a nett producer of electricity.
The Mt Difficulty vineyards are managed in a way that reflects our commitment to be as gentle with the environment as we possibly can. We use no harsh insecticides or herbicides, preferring softer alternatives instead, many of which are organically certified.
The harsh climate in Central Otago gives us a unique opportunity to grow grapes with a lower impact on nature than other regions. We have intensely cold winters, which take care of a number of pests. Our warm to hot summers have very low humidity which limits the incidence of diseases such as botrytis, and so we are able to keep our vineyard management techniques relatively simple.
The sensitivity of our attitude towards the environment is ever evolving: currently, we are considering a more organic approach to viticulture. While many current operational systems are strictly organic by definition they do not, at this time, take into account carbon losses through cultivation. This process of trying to remain organic while also reducing our carbon footprint is the area of viticultural management we are trying to resolve.
The Hippocratic Oath requires practitioners to 'First, do no harm': our stewardship of the land also follows this dictate.
In doing this we can be confident that the unique and evolving story of our place will continue to be told in our wines.