NZ Sauvignon Blanc research project

May 2006
NZ Sauvignon Blanc programme

The first large-scale wine research project for New Zealand aims to help the industry retain and understand the unique flavour of Marlborough Sauvignon Blanc and to ensure it maintains its international reputation.

The Marlborough Wine Research Centre is collaborating with University of Auckland (chemistry department) in the $9.6 million, six-year project funded by the Foundation of Research, Science and Technology. MWRC receives $3.4 million, as a sub-contractor to Auckland University, along with Lincoln University and HortResearch. The wine industry also has a major contribution in cash and kind. The programme began on July 1, 2004.

MWRC and Mike Trought, science leader, are concentrating on the regional factors which make Marlborough sauvignon blanc unique and highly valued.

He says the programme has put the work of the MWRC (opened in 2001) on a firm footing, with a solid early focus into what is the premium product of the region and the flagship varietal for NZ wines.

While it is known that sub-regional differences in environmental factors, such as soil and climate, produce various Marlborough sauvignon blanc styles, the extent to which those environmental factors contribute to differences in fruit composition and wine styles is poorly understood. So, the project seeks to understand how the sub-regional differences impact on vine phenology, fruit aroma and flavour development.


The development of a management support model which will predict the effects of various environmental factors on the Marlborough sauvignon blanc, such as site selection, grape clones and root stock, irrigation, leaf removal, management, skin contact time during wine making and yeasts used. Yeasts release the precursors into volatile forms in juice and wine.

In collaboration with Lincoln, the MWRC is looking at what happens when environmental controls turn on the genes which result in the expression of flavour during the development of the berry.

The aim is to understand what is going on with changes in location, soils and climate, between sites and between seasons. However the degree of influence over these factors and their expression in the wines is constrained by the consumers expectations of a Marlborough sauvignon blanc.

Work to date

Mike Trought will deliver a paper at a terroir conference in Bordeaux, presenting the results from research into the impact of changes in soil texture within a vineyard on vine development and wine quality. The young alluvial soils of the Wairau Plains produce the world-famous Marlborough sauvignon blanc, but they contain considerable variation in soil texture.

Vines rows generally north and south, across the plain in which old river channels run east-west, an average of 50m apart. This creates changes within rows from gravelly soils to deeper silt loams. Vines in more soil cover develop greater trunk circumferences and produce more pruning weights. However vine phenology (growth, development) is more pronounced on the gravely soils, which gives riper fruit, and consequently wine style, on any given date.

Achieving optimal fruit composition at harvest to produce the perfect wine is the aim of grape growers. However, there can be eight to ten-fold differences between vines in yield within a single vineyard, which may in turn impact on fruit composition. Variation in maturity can produce overripe and unripe flavours within the fruit.

With todays precision agriculture techniques such as global positioning satellites (GPS) and yield monitors on harvesters, the variations can be mapped within vineyards, to lead to ways to manage the fruit composition variability.

The research work compared the attributes of vines and fruit from extra small vine circumferences and extra large circumferences. The smaller vines were growing in gravelly soils and the larger ones in silt loam. There were differences in fruit yield, brix, titratable acidity, pH, pruning weight and leaf chlorophyll levels at harvest.

The proportions of XS and XL vines, once known, can then be used to predict the wine styles of any vineyard. In some cases, vineyard areas may be managed differently, through irrigation, leaf removal, fertilising and harvesting, to minimise the variation.

Also, understanding the different responses of various parts of the vineyard to factors such as water stress and the impact on fruit composition overall, will provide an opportunity to describe the consequences of different seasons on fruit composition and wine style from a particular vineyard.