From Grove to Glass
From Grove to Glass
In Florida, most oranges bloom in March-April. The “early” varieties, such as Hamlins and Parson Browns , reach maturity in October through January. The “mid-season” varieties such as the Pineapple Orange reach maturity in December-February. “Late season” varieties such as the Valencia, matures the following March-June.
All citrus, including oranges, must ripen on the tree. Citrus does not ripen once removed from the tree. Grove managers take representative samples of oranges from a particular block of trees, about 40 pieces of fruit for a 40-acre block. The juice is squeezed from the sample fruit and the juice is tested for two main attributes — brix and acid. From these two attributes, the sugar to acid ratio, which determines the flavor of the juice, is determined. Juice must meet minimum standards in order for it to be sold as 100% Florida Orange Juice.
The brix content (mostly soluble sugars) is determined using a hydrometer to measure the specific gravity, which is converted to degrees brix. Then, using a titration method, the percent acid is determined using sodium hydroxide and a phenolphthalein indicator. The ratio of the brix to the acid content can then be calculated. The minimum maturity for oranges varies during the season, but generally it is a minimum of 8.5 brix with a 10 to 1 ratio. Many juice processing plants will have even higher minimum maturity standards.
Once a block is determined ready for harvest, a crew of harvesters is sent to pick the entire block of fruit by hand using wooden ladders and canvas pick sacks. In Florida, almost 98% of all oranges are harvested by hand. There are a few experimental mechanical harvesters in use. The most popular is the trunk shaker, a machine that clamps onto the trunk of the tree and violently shakes off the fruit into a catch frame. Currently, there is no cost advantage of using mechanical harvesting vs. hand harvesting. The pickers dump the fruit into plastic tubs that hold approximately 900 pounds of oranges. A special truck, called a “goat”, will then come through the grove and, using a hydraulic boom, pick up the tub and dump it into the back of the goat into a special body. The goat then goes outside the block of trees and the body raises up and dumps its load of oranges into a large, open tractor-trailer that holds about 45,000 pounds of oranges. A truck-tractor then hauls the trailer to the processing plant.
Written by Chet Townsend, “UltimateCitrus.com”