68 THE CANNING OF FOODS. 



edge, after which the end is put in place, and the can passed through 

 another machine which crimps the end to the sides. This end con- 

 tains a small hole or tip. The can then rolls, head downward, into a 

 V-shaped groove which contains flux, and continues its rolling in 

 another section of the groove containing solder, and it is here that the 

 final sealing is done. The heating of the contents, due to the hot 

 solder, causes some steam to be generated, and it is for the purpose 

 of allowing this to escape that the piece of tin is placed within and 

 under the vent. When the can leaves the soldering trough it is turned 

 over and the vent closed or tipped. With sanitary cans no tin nor 

 vent is needed, the cap being attached and sealed by machinery. 



The cans are then placed in trays, the standard size being 35 inches 

 square and 3 inches deep. Each tray will hold ICO tall or 86 flat 

 standard No. 1 cans, the cans being on end in a single tier. The test 

 for leaks is to set the tray in boiling water for a few seconds and 

 watch for bubbles. Eight trays make a basket, and this constitutes 

 a charge for the retort. 



The process consists of heating at 220 F. for 30 minutes, then 

 taking out the fish, venting, and retipping, and giving a subsequent 

 heating for 1 hour and 15 minutes at 250 F. When open-top cans 

 are used, the filled cans are run through an exhaust box very slowly 

 so that they are thoroughly heated before the cover is attached. 

 Venting becomes unnecessary, but the time of cooking remains un- 

 changed that is, the single heating is equal to both periods under the 

 old method. The hot cans are immersed in lye to remove grease and 

 oil and are then cooled in water. The net weight of the 1 -pound 

 tall or flat can should average 16 ounces. 



SARDINES. 



The sardines caught on the Pacific coast are much larger than those 

 taken in the East and are handled in a different manner. They are 

 caught in nets at night, and on being brought to the factory in the 

 morning are put into bins and kept wet with running water for some 

 hours. They are then dressed, scaled, heads and viscera removed, 

 and again thoroughly washed in two or more changes of water. 

 They are next dipped in strong salt brine for a few minutes, rinsed, 

 and placed in wire trays to dry. In order to expedite the drying the 

 trays are carried through a mechanical dryer so that all surface 

 water will be removed. The crates are then dragged through a vat 

 of boiling oil, the length of time being that necessary to cook the 

 fish thoroughly, usually about 5 minutes. They are left in the crates 

 until cool, which is usually until the following day, placed in the cans 

 by hand, oil or sauce added to fill the interspaces, carefully exhausted, 

 and processed at 240 F. for 1 hour and 15 minutes. 



