There are certain advantages in not processing. In the first place a better colored and flavored product is often obtained, particularly if the catsup is made from pulp, and especially is this true if the pulp is a little overcooked, and consequently a little dark in color. Then there is the advantage of the saving on labor and on steam, which is a large item. Running a half dozen or more process tanks constantly draws heavily on the steam supply, and the processing means more handling of the bottled product, and therefore more labor. It also means more equipment, with the floor space which this equipment takes—not only a lot of tanks, in case stationary tanks are used, but iron baskets to hold the bottles, electric or steam hoist, and trolley track. Not only the original cost but the maintenance of this equipment is considerable. Then there is a certain amount of breakage during processing. Also, steam must be kept up late at night for no other purpose than processing.
When no after-sterilization is used all of this is done away with, and the only equipment needed to supplant the above is a steam-jacketed pipe to conduct the catsup to the filling machine, and a continuous hot air sterilizer for the bottles, which usually consists of a vertical shaft, and takes up practically no floor space.
Process Method
I will discuss in detail the process method first. The catsup should be filled as hot as possible, and it is a good idea to use a steam-jacketed pipe in this case, as well as in the non-process method, because the hotter the catsup is when bottled, the quicker the center of the bottle will be raised to the desired temperature, and the quicker the sterilization can be accomplished. The catsup should be 180 degrees or above when it enters the tank of the filling machine, and it should be placed in the process tanks as soon after sealing as possible.
The process tanks may be large stationary iron tanks, or a continuous pasteurizer such as is used in beer bottling plants may be used. The latter is the better way, as it is compact, automatic, takes up very little floor space, and there is no danger of over-sterilization, or of scorching by leaving the bottles in the tanks after the water is drawn off, where the air cannot get at them to cool them off. The reason continuous pasteurizers are not used more commonly is their expense, although they should pay for themselves in a few years by the labor and steam they save, it being only necessary to keep one large tank in operation instead of a half dozen or more.
If stationary tanks are used, which is usually the case, the catsup should be taken out of them as soon as the water is drawn off, so that the air can get at the bottles and cool them off. To leave the hot, bottled catsup in the tanks over night is almost as bad as piling a lot of hot pulp close together, the only difference being that there is a little more room for air circulation between the catsup bottles, but not much.
Time and Temperature
There is a great difference between the time and temperature employed for processing in different factories. Some packers process as low as 170 degrees F., it is said, while others use a temperature very close to the boiling point. In some plants pint bottles receive only a 30–minute process, while in others they get over an hour.
The proper time to use depends upon the temperature that can be maintained at the filling machine, and the rapidity with which the processing can be done after the filling. If the packer can hold his catsup around 180 degrees at the filler, and is so equipped, either with continuous pasteurizers or stationary tanks, that he can process immediately, an hour is ample time for pints, and 45 minutes is sufficient for half-pints; other sizes accordingly. If, however, the temperature of the catsup at the filler often falls to 170 degrees or below, and the catsup is filled faster than it can be processed, so that at times much of it must stand for an hour before it can get in the process tanks, 15 minutes additional for each size bottle had better be added to the above.
This may seem to some packers like a long time. All one has to do to convince himself that it is not too long is to take one of those thermometers which are made especially for determining temperatures at the center of the bottle, and put it in a bottle of catsup while it is being processed, watch the mercury rise, and note the time it takes to bring the center of the bottle to the temperature of the water surrounding it. You will find that if the water surrounding a pint bottle is 200 degrees, and the temperature at the center of the bottle is 160 degrees, it will take just about an hour to bring the catsup at the center of the bottle up to 200 degrees.