The origin of the stuffed olive is of very recent date, but by whom originated is not quite clear. According to an authority1 on Spanish olives, stuffed olives were unknown before 1893-4. It was in 1895 that Señor Picasa, the general manager of the Sevilla Packing Company, had seen olives stuffed with pimientos in Spain, and in the following year introduced them into the United States, the company packing them under the copyrighted name of “Pimola.” In 1897, a Spanish house packed pepper-stuffed olives, and later on other firms also, among the latter many American firms. As the pimiento is grown and prepared in Spain, and labor cheaper there than here, the industry has been practically transferred to that country.
The operation of stuffing consists in removing the pit and filling the cavity with some other substance, particularly pimiento, these forming the bulk of the stuffed olive trade. The bright red of the latter gives a pleasing contrast with the green, and the mild pungency is very agreeable to many persons. Pickled celery, capers, etc., have been used, but were not so favorably received, and at present, the substances used to any extent, aside from the pimiento, are Manzanillos stuffed with pieces of Queens, and some stuffed with anchovies for the South American trade. Pitting machines have been devised, and also machines for stuffing the olives, but the work done by the stuffing machines is crude as compared with hand work. The olives used for stuffing are the Manzanillo which are smaller than the Queen. The sizes are as follows:
They are packed in barrels of about 45 gallons capacity, and like the Queen, are repacked into individual containers in this country.
A few olives are packed with a mince of capers, anchovies, truffles, etc., and the olives preserved in oil. A few are also packed for garnishing, in which cubes are cut out and the spaces filled with bright peppers.
Domestic
In California the commercially prepared olives are practically all ripe, only a very limited quantity of green ones being prepared. Since the olives, even on the same tree, ripen at various periods, three pickings are made during the season, when olives well colored and of an equal degree of ripeness are taken. In excessively ripe olives, the skin toughens, and the fruit is difficult to pickle. The trees are pruned so as to keep them low enough to be reached by the harvesters on step ladders, in order that all picking may be done by hand. The picked fruit is taken to a central point to be filled into boxes or barrels, for transportation to the factory. For the best grades of olives, particular care is taken during this part of the work to avoid bruising the fruit, which is picked into canvas bags, pails, etc., then poured into barrels partly filled with water, so that the water will furnish a cushion for the fruit. The olives are transported to the factory in these barrels. These precautions are taken as bruised spots soften and become black, and the resulting processed fruit will not be of first quality. Many growers deliver fruit dry in lug boxes, but bruising and crushing are liable to occur during transportation. The fruit is delivered into a hopper filled with water, then from the hopper into boxes where the fruit is drained. The fruit is delivered in the factory to be first sorted which is done on a moving belt, and here all stems and defective fruit are removed as the fruit is carried slowly past the workers who sit or stand on either side. In some factories the sorting is done after the fruit is pickled, but is much more difficult due to the change in color through the action of the lye and of oxidation. The fruit is next passed to the grader, which separates the various sizes. From the grader the three largest sizes are each delivered to a moving belt to be sorted for color, degree of ripeness, and culls, as the curing must be modified to suit the particular degree of ripeness, a crisp firm olive requiring a heavier treatment than does a riper, softer-textured one. The olives as sorted, are passed to small side belts, which thus deliver fruit uniform in size and color to the receiving boxes. Great care is taken in the sorting of olives, different varieties are not mixed, nor even fruit of the same variety but from different localities. In grading for size by machine, 1/16 of an inch is the variation between each size and the next; those less than 10/16 are removed to be used for other purposes. When the minimum is due to the variety and not to stunting, the fruit may be pickled, because aside from the larger proportion of pit, the flavor is equal to that of the large fruit. Usually the smaller olives were used for oil, but more recently are used for relishes and sauces. The sizes upon which the different grades are made are based upon the short diameter of the fruit, and have been adopted by the California Olive Association:
The olives are placed in an alkaline solution, usually sodium hydrate as it is stronger in action than potassium hydrate. The strength varies with the different packers but is generally in the neighborhood of 1½%. After 6 to 8 hours, the lye is drawn off and the olives exposed to the air in order that they may oxidize and darken, since the lye removes some of the natural color. The operation is repeated with the same strength or less of lye solution and the fruit exposed to the air until examination of the pulp shows that the lye has penetrated to the pit. The lye solution is then replaced with clear water which is changed twice a day, until the lye and bitterness are removed, which requires from 4 to 8 days. The olives are then treated with brine solutions, starting with 1 %, and increasing the strength at intervals of about 2 days until about 4 % is used, when they are ready to be put in glass jars or cans and sealed.
The brine is used very weak at the start and gradually increased so that the osmotic action may be so controlled as not to cause the fruit to shrivel as it would if placed in a strong solution at the start. Some packers permit the olives to stay in the weak brine long enough for fermentation to take place as done with the imported green olives so as to develop an acid flavor. The more recent tendency, however, is toward packing them with the least possible change, and to depend upon the distinctive natural flavor of the fruit itself. A similar tendency toward retaining the natural color, rather than that induced by oxidation, might be advantageous.
If it be the intent to hold the olives in bulk, they are treated with increasingly strong brines until 10 to 12½% is used, the latter amount being required to carry them safely through the summer.
The process is modified in practise to suit the conditions, as variations in varieties of fruit, in temperature, and in the lye have to be considered. There are also variations in practise due to individual experience. During the time the olives are in the various solutions they are stirred frequently, so as to change their position in the vats, and also to change the solution in contact with them. The stirring was, and is done yet in some cases, by hand, with wooden paddles, which is laborious besides causing more or less damage to the fruit. Recently compressed air has been piped to the vats and directed into the solutions with sufficient force to keep the olives agitated. This method is said to hasten the action of the lye solutions with consequent improvement in the fruit. It also obviates the drawing off the solutions and the exposure of the fruit to the air, as a certain amount of oxidation takes place in the solution.
As the operators place the olives in the bottles or cans, the soft and defective ones are discarded. The containers are then filled with a 3 % brine at a temperature of 175 or 180 degrees F. The air is exhausted, during which the temperature is raised to 185 degrees, and the containers sealed, after which they are processed. The large olives in a 26 ounce glass jar are cooked for 50 minutes; extra large, 55 minutes; mammoth, 58 minutes; and colossal 60 minutes; at 240 degree F. in some factories, or for a longer period if processed at a lower temperature.
The time required for heat to penetrate to the center of an olive is longer than has been generally supposed. This was determined by carefully drilling into the pit, first with a fine drill and then with increasingly larger ones, until an eighth inch hole was made. The bulb of a small thermometer was inserted, and to prevent heat being carried to the bulb by means of the glass stem, sections of olives were placed around the stem immediately above the olive being tested, and tied securely. Jumbo olives at room temperature placed directly in a boiling bath required on an average fourteen and one-half minutes for the temperature to reach 209 degrees F., which is practically the maximum which can be attained under the conditions. When the olive was placed in cold water and the bath heated rapidly under conditions similar to home canning, the average time required to reach 209 degrees F. was 29 minutes. The former experiment represents a more favorable condition for heat penetration than prevails in factory operations, and the latter probably the least favorable, but both show that in the ordinary process all parts of the olive do not reach the high temperature supposed to be produced by that of the bath for more than a few minutes.
At the University of California ripe olives have been canned without brine. After pickling, the olives have been placed in 3 % brine for several days, then heated in the brine to about 180 degrees F. after which they are taken from the brine, put in the bottles or cans, sealed, and processed. No shrinking, wrinkling, softening, nor change in color is said to take place. By the elimination of the brine in the container, there results a saving in freight of 31.5 % with cans and 16.6 % with bottles.
The history of the olive and its method of preparation show that no organisms pathogenic to man are normally present and that if such organisms be associated with it in any way, it must be from the outside and through local infection.
More care is required in processing at high temperatures, than at boiling. A high internal pressure is developed inside the cans or jars, due to the expansion of the contents and of the enclosed gases, which has a tendency to loosen or blow off the covers. This tendency may be overcome by applying air or water pressure on the outside of the cans or jars to counteract that generated within. This is done while they are inside the retort and by means of automatic pressure controllers. There is no essential difference in the sterilizing and cooling of tin cans and glass jars, both forms of containers are responsive to treatment with high temperatures and both require proper care and handling. As with pickled olives, however, glass jars permit the purchaser to see the size and the condition of the fruit.
The canning of ripe olives in California was originated by F. T. Bioletti, zymologist in the University of California, and came about through an investigation in 1889 on the spoiling of olives. When pickled olives were held, the quality deteriorated in some of them, they softened during the summer, and seldom remained in an edible condition for a year. As a result of his experiments on methods of keeping, he found that the olives could be sterilized in sealed containers and be kept in edible condition indefinitely. The commercial application of the method and the popularizing of the ripe olive is due to Mrs. Freda Ehmann, a pioneer olive grower, who applied scientific methods, with marked success, to both the development and canning of the olive.