10 BULLETIN 35, U. S. DEPARTMENT OF AGRICULTURE. 



grapes held as well in. this coarse sawdust as in the fine material and 

 that the large particles separated readily from the grapes and could 

 be easily shaken or blown out. 



A most effective method of dislodging the sawdust is by means 

 of an air blast, which frees the particles from the bunches without 

 in any way injuring their appearance. When large quantities of the 

 grapes are to be separated from the filler it is advisable to accom- 

 plish the work by means of such a device. In the investigations of 

 the Bureau of Plant Industry a tray or frame covered with wire net- 

 ting of one-fourth inch mesh has been used to good advantage. The 

 packages of grapes are emptied into the trays or on the frames, and 

 by means of an air blast the sawdust particles are blown through the 

 wire netting, leaving the fruit free. For grapes with a tender skin 

 this blast should not be too strong, 10 or 15 pounds pressure being 

 ample to dislodge all the particles. The use of an air blast is not 

 necessary to free the grapes from the coarser grade of sawdust, dis- 

 lodgment being accomplished by merely shaking the bunches, as is 

 done with the cork-packed grapes. The air blast greatly facilitates 

 the work, however, and its use is suggested from that standpoint 

 alone. 



The quality of the sawdust and its method of preparation are 

 of prime importance. 'It is necessary to have the redwood abso- 

 lutely pure, as the slightest mixture of other woods, such as pine, 

 cedar, or spruce has been found to taint the flavor of the grapes very 

 quickly. Those who are interested in the packing of California 

 grapes in this way should use every precaution to obtain redwood 

 sawdust of the best quality. Some of the inquiries received by the 

 Bureau of Plant Industry indicate that the importance of this point 

 is not always sufficiently appreciated. Plates I, II, and III show 

 natural-size photographs of the different grades of ground cork and 

 redwood sawdust under observation during the course of the work. 

 Plate 1, figure 1, shows the size and shape of ground-cork particles 

 taken from a barrel of imported Almeria grapes. The suitability 

 of this material is well known and no comment is necessary here. 

 Plate I, figures 2 and 3, show the nature of the cork used in the 

 Bureau experiments to show the relative adaptability of cork and 

 redwood sawdust as. grape-packing materials. It will be noticed that 

 the coarser grade shown in Plate I, figure' 2, is more uniform than is 

 that used by the Spanish packers. Plate 1, figure 3, shows the fine 

 cork used to determine whether or not the small size of the sawdust 

 particles was responsible for the better holding quality of the grapes 

 in that material. Plate I, figure 4, shows a sample of ground cork 

 waste offered by one of the cork-manufacturing companies during 

 1912. The shreddy nature of this material makes it unsuitable for a 



