Orchard Managers Need to Know Importance of Crop Load Densities, Claims Study

30 Nov 2016 ---Orchard managers can improve the quality of the cider they produce by gleaning more information about key issues such as how crop load densities impact cider quality, according to the authors of a key study. Cider is becoming an increasingly popular drink in the US with figures showing that cider consumption increased by more than 850 percent in the last five years.

The study, published by the American Society for Horticultural Science, into the production of cider, was carried out by Cornell University's Gregory Peck, scientists Megan McGuire, Thomas Boudreau IV, and Amanda Stewart from Virginia Polytechnic Institute and State University.

They carried out extensive research and field experiments to assess the impact of three different crop load densities on apple fruit and cider quality.

The treatments were carried out on a 14-year-old orchard in Winchester, Virginia on York apples, which are mainly used for processing into juices and vinegars.

To experiment with different crop loads, York apple trees were hand-thinned to three difference levels: low, medium and high crop loads.

After fermentation, it was noted the difference in polyphenol content between loads.

The medium crop load had 27 percent and the high crop load had 37 percent greater total polyphenol content than the low crop load.

Meanwhile, yeast assimilable nitrogen (YAN) concentration in juice made from fruit from the low crop load treatment was 18 percent and 22 percent greater than the medium and high crop load, respectively.

But the YAN concentrations in juice from the medium and high crop load treatments were similar.

"Our study suggests that apple juice and cider quality can be altered by crop load management," the authors said.

"Management strategies for chemical thinning should take into account the resulting fruit quality, especially YAN concentration in juice pre-fermentation and total polyphenol concentration and total alcohol in fermented cider."

The authors noted should be aware of the potential for YAN deficiency in fruit from orchards with a high crop load.

"YAN deficiency can be rectified through the addition of commercially available YAN supplements when warranted," they added.