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A new method of estimating grape yield may provide the boost the Australian wine industry has been waiting for.

Amanda Mader, a viticulturist at Yalumba Wines, says if you can’t measure the grape crop accurately, vines can’t be managed for quality improvement.

“Currently the standard method of estimating yield requires a person to count flowering structures, the number of berries per bunch and weigh the mature bunches,” she said.

“This limits the sampling frequency and, as a result, the accuracy.”

Amanda’s idea is to estimate yield by measuring tension on the trellis wire, the structure holding the vine.

As the grapes grow on the vine, tension on the wire also increases. By continually measuring the wire tension, bunch weights can be accurately estimated up to the time of harvest.

Using this method, Amanda believes the variance between actual and estimated tonnage can be reduced to five per cent, which is half the current wine industry standard.

“The economic benefits associated with improved crop estimation techniques are substantial and believed to be in the order of tens of millions of dollars a year.

“At the same time, overall wine grape quality will lift as the crop can be manipulated, via shoot and bunch thinning, when the most benefit can be achieved.”

Amanda’s method may also provide useful data on berry growth dynamics and continuous changes in bunch weight due to variations in rainfall, climatic conditions and irrigation practices.