Mechanical Harvest of Hard Cider Apples

Hard cider sales increased 40% in the United States in 2011, and there is a need to provide growers with production information to support this new emerging industry. Apples for hard cider are mechanically harvested in Europe, with shake-and-sweep equipment. This study investigated the use of an over-the-row mechanical raspberry harvester (Littau Model OR0012) with a trellised planting of ‘Brown Snout’ cider apple in northwest Washington. The region is a center for processing raspberry production and mechanical harvesters sit idle in the fall when apples are ready for harvest. The study was carried out in 2011 and 2012 at Mount Vernon, WA, trees were planted with 6-ft in-row and 12-feet between-row spacing, and there were two replications of M9 and M27 rootstock with 10 trees per plot. There were no differences due to rootstock (P≥0.05) and data were pooled. Total weight per plot of harvested apples did not differ between hand and mechanical harvest either year (P=0.6127 and P=0.5666, respectively), however yield was lower in 2011 than 2012 (100 kg and 26 kg, respectively; P=0.0002); Brown Snout is alternate bearing and 2012 was an "off" year. Significantly less time was needed for mechanical harvest than for hand harvest in 2011 (40 hours and 7 hours, respectively; P=0.0018), however there was no difference in 2012 (16 hours and 10 hours, respectively; P=0.1446). Each year, there were almost twice as many broken spurs per tree with mechanical harvest (2.4 and 16.0, respectively) than with hand harvest (1.3 and 7.5, respectively); although these differences were not significant (P=0.3082 and P=0.1064, respectively), increased tree damage may lead to a decline in tree health and should be evaluated over the long term. Juice was pressed immediately after harvest and both years there were no significant differences due to harvest technique for °Brix (P=0.9234 and P=0.6830, respectively), pH (P=0.1075 and P=0.5055, respectively), specific gravity (P = 0.4950 and P=0.9083, respectively), malic acid (P=0.0823 and P=0.9529, respectively) and % tannin (P = 0.5301 and P=0.4309, respectively). In 2011 fruit was placed in cold storage (32 °F) for 3 weeks, and in 2012 fruit was cold-stored for 2 and 4 weeks. Both years there were significant differences between juice at harvest and after cold storage for °Brix (P=0.0006 and P=0.0007, respectively) and specific gravity (P=0.0003 and P<0.0001, respectively), while there were no differences in pH, malic acid, or percentage of  tannin either year.