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of this technology. Equipment manufac- turers have responded to these concerns. Pellenc's Selectiv' system is not only a mechanical harvester, it also destems and removes material other than grapes. Waste items such as stems, leaves and pet- ioles are left on the vineyard floor and do not have to be managed at the winery level, increasing the speed at which atten- tion can be given to the fermentation. The bins coming into the winery should be ready for mixing, sampling and testing for pre-fermentation additions. Sorting in the winery In the absence of field sorting, the next option is sorting in the winery. Enter the Bucher Vaslin R1 and R2 grape sorters. The technology among pieces of grape- sorting equipment is relatively similar (cameras and computer memory), however Bucher Vaslin incorporates the sorting pro- cess into the other grape-processing equip- ment it manufactures. Elevators feed the Delta series destem- mer, and fruit drops onto vibrating sort- ing tables to give some separation to the berries as they are fed into the R1 or R2 grape sorters. What I found remarkable in my experience with the R1 was the rela- tive speed at which sorting occurs: It is capable of up to 5 tons per hour, while the larger R2 can sort at a rate of at 10 tons per hour. Behind the berry sorting is a technology made possible by the relative low expense of memory in the computer world. Images of the fruit are taken as grapes pass in front of a camera; criteria to accept fruit have been preprogrammed in to the computer, and berries and other particles that fall outside the criteria for acceptance are rejected. Just seconds after each picture is analyzed, an air jet pushes rejected particles out of the main process- ing stream. Programming is easy, but it takes some time, as you need to select berries that meet your acceptance criteria. What fol- lows is a series of stops and starts while you examine the quality of the accepted stream versus the reject stream. Most sys- tems allow some tweaking once the pro- cess has started. From a labor standpoint, an experienced operator should be moni- toring both output streams and making adjustments as required. While there is data to support differ- ences in the chemical properties of the waste stream versus what went in to the tank and for fermentation, it is unknown whether these differences affect overall wine quality. Research conducted at the Teaching and Research winery at the Uni- versity of California, Davis, in 2013 may shed light on this. UC Davis researchers (in conjunction with Pellenc, Bucher Vas- lin, Plata Wine Partners and Silverado Winegrowers) undertook a study to try and answer this question. Results were to be released at the ASEV National Confer- ence in Austin, Texas, in June; watch for updates from Wines & Vines. Settling by flotation Technology also allows us to re-evaluate traditional winemaking practices. Take the process of cold settling juice to remove grape solids, for instance. While it is the winemaker's choice to ferment with high solids (there is some benefit to the yeast and malolactic bacteria), these solids con- tain enzymes (generally referred to as esterases) that decrease the overall fruitiness of the wine by degrading the ester compounds formed during alcoholic fermentation. In the sim- plest sense, the juice is pressed off the skins and placed in tank at a low temperature (50° F) and settled until the solids content is less than 1%. The juice is then racked to another tank, warmed slightly, and fermentation is initiated. This process requires two tanks that have to be cleaned, resulting in twice the amount of water used. Technology carried over from the wastewater treatment field is a modifica- tion of a system referred to as the Jame- son Cell. The cell is very simple in that after the juice is pressed, it is conveyed to a holding tank, in which small bubbles of inert gas are introduced through the bot- tom. As the bubbles rise, they carry along with them the solids, which are skimmed off the top of the tank. The clear juice on the bottom of the tank is then conveyed to the primary fermentor. The process saves a minimum of 24 hours in tank space availability as well as the water required to clean the settling tank and the energy required to cool the juice during the settling period. American Tartaric Products offers a modified approach to the Jameson Cell with its GB BevTec unit that operates as a closed system. The prin- ciples of flotation are the same, and modi- fications to the system are possible for a system capacity of up to 8,000 gallons per hour. Removing solids with cross flow Some manufacturers have chosen to mod- ify existing technology (notably cross- flow filtration systems) to accommodate the removal of solids from juice. Cross- flow filtration has been a viable industry- accepted filtration technology for more than a decade. A small tube acts as the filtration medium. The juice/wine is passed parallel to the membrane pores, and the high pressure of the inlet side forces the wine/juice through the pores to 38 W i n e s & V i n e s J U LY 2 0 1 4 Grapes are fed from vibrating sorting tables into Bucher Vaslin R1 and R2 sorters, which use images of the fruit passing by to remove undesireable berries and MOG. Solids are skimmed off the top of the GB BevTec flotation unit offered by American Tartaric Products. View Video: Watch a continuous flotation unit in action in this video shot by wine equipment manufac- turer Della Toffola. The company's FLCV "flotators" feature one or two separation tanks. T E C H N O L O G Y