FILLING THE FINISHED PULP AND STORING THE CANNED PRODUCT
Filling Devices for Five Gallons
The most commonly used containers for pulp are the five-gallon can, the
No. 10 and the No. 1 can.
The usual method of filling 5–gal. cans is to draw the pulp from the
finishing machine by means of a large, heavy wall, single line hose
filling one can at a time. Some packers use a manifold by which five
cans can be filled at once. This requires a lot of valves and enamel
lined pipe fittings, and unless the operator is very expert the manifold
will not do the work any faster than a single line hose.
Square Can and Round Can
The square 5–gal. can is preferred by nearly all packers to the round
can. The round can is hard to handle, hard to stack, and is very
wasteful of space wherever it is stacked. The square can is to be
preferred in every way.
Testing for Leaks
When new cans are being used it shouldn’t be taken for granted that they
are absolutely free from leaks, as it is sometimes found that a large
percentage of a car of cans will run bad, and the packer should test
representative samples from the car as soon as it is received, so that
he can reject it and secure other cans if the car doesn’t test up right.
The best way to do this testing is with a small tank of water, a
one-eighth inch air line, giving about four pounds pressure, and a can
tester. A simple kind of can tester can be easily constructed in any
blacksmith shop, and merely consists of an iron brace to fit around the
can and which can be quickly tightened over the can and released, and a
soft rubber semi-circle to fit tightly into the cap hole and which is
gripped at the top and held in place by one side of the brace. The
one-eighth inch brass air pipe passes through the center of the rubber
semi-circle and into the can. As soon as the can is tightly clamped and
the cap hole sealed by the rubber, the air is turned on and the can is
immersed in the water. The leaks show up very quickly under a four-pound
pressure, and a dozen cans can be tested in as many minutes.
Washing and Steaming
New cans, as well as old ones, should be thoroughly washed and steamed
before filling. There is often a fine, light colored dust in new cans
which a good strong spray of water properly directed into the inverted
cans will remove. Through the same pipe which directs the spray of water
into the cans, the cans can be steamed by means of a simple arrangement
of valves on the steam and water pipes. A washing and steaming rack can
easily be fitted up which will wash and steam a half dozen cans at once.
A single stream of water entering the cap hole of the inverted can is
not sufficient to clean it. The pipe which enters the cap hole should be
capped, and about three holes drilled into this cap at a slight slant so
that the upward spray of water will strike three different spots in the
bottom of the inverted can, and make the washing thorough.
If the average packer could see just how little of the inside surface of
his 5–gal. cans is actually washed, he would be surprised. About fifteen
seconds is sufficient time to spray the inside of the cans, and then the
water valve can be closed and the steam valve turned on. The steam
should be kept on for a full minute and kept on strong. The idea is not
merely to heat the can but to sterilize it, at least to some degree,
before the pulp is admitted. The average employee steaming 5–gal. cans
leaves the steam on ten seconds at the most, and often not more than
three seconds. Such a short steaming does very little good. The space of
time between the steaming and filling should be just as short as
possible. The employees should not be permitted to keep a half dozen
cans steamed ahead all the time so that they are cold by the time the
pulp enters them.
Filling and Capping
As stated in the previous chapter, the temperature of the pulp when it
is filled should be at least 170 degrees F. and preferably above 180
degrees. The cans should be filled clear to the top with the pipe or
hose which conducts the hot pulp from the finisher; they should not be
topped off out of a dipper which contains luke warm pulp and is used for
topping purposes. It is not necessary to do this topping and the
practice should not be permitted. The sponges which are used for wiping
the edges of the cap hole should be kept in a bucket of clean, hot
water, and put back in the bucket after being used on a truckload of
cans. The capping and tipping job should undergo inspection before the
cans are trucked away.
Handling Filled Cans
Cans of filled pulp should be handled carefully. The cans should be set
down easily, so as to strain the seams as little as possible. Of course
the laborer wants to let go of cans of red-hot pulp just as quickly as
possible, but it is not necessary to drop them several inches, and the
employees should be taught to set the can on edge and then let its
weight straighten it up. If the employee is given good thick gloves it
is just as easy to handle the cans carefully. I had occasion at one time
to check up on the percentage of swells resulting from one pile of pulp
which was stacked by an old hand who knew how to handle pulp easily and
carefully, and another pile from the same day’s run which was stacked by
a gang of new and uninstructed help who simply picked the cans off the
truck and dropped them in place. These were second-hand cans, and the
difference was considerable.
Both filled cans and empty cans should be handled almost like eggs. One
large pulp packing concern is particularly cautious about this, and it
is certainly soothing to the nerves to see their employees handling
5–gal. cans after witnessing the rough and tumble methods in the average
plant. They know that it pays to be particular, and that they can get
three years’ use out of almost all of their 135–lb. plate cans, and not
have many swells either. This concern rarely sells any of their pulp,
but puts it up for their own use, to be made into bean sauce, catsup,
soup, etc., during the winter months.
Advantages of Separating Batches
Some packers stack their pulp away without dating it; others date each
day’s run; while others stack each batch separately. The latter system
is practicable where the pulp is cooked in large batches of about 300
gallons or more and in working up the pulp during the winter months it
is a great help. For instance, suppose part of the pulp is to be used
for catsup and part for bean sauce. The packer can take batches one to
fifty, for example, open one can from each batch, examine it for color
and microscopical analysis and he knows exactly what he has in that
stack of pulp, which may be three thousand cans. He can select the
various batches to be used for the purpose to which they are best
adapted, and he can be absolutely sure that each can in a batch is
exactly the same in every respect.
Take another example: We will say that the packer is selling his pulp.
His records show that on September 20th and on October 2nd, for
instance, he had a lot of bad tomatoes; shipments received on those days
were unavoidably held up and he had to make the best of the situation.
He knows, however, that on those same dates he had a lot of good
tomatoes which came in by wagon haul and that they were run up at the
same time. He has a large order for pulp from a catsup maker who is very
particular about the microscopical analysis of the goods he buys. In
order to play absolutely safe, the packer can take a sample from each
batch of the pulp run on September 20th and October 2nd, and if a half
dozen batches run too high he can omit them when he makes the shipment
to this buyer. If he preserved a sample from each batch run on these
dates at the time they were run, which is the better way, it makes the
sorting out of this pulp a very easy matter. He thus eliminates the
danger of the loss of a good buyer by sending him even a comparatively
small quantity of pulp which is high in micro-organisms.
It may seem to one who has never tried it that stacking each batch of
pulp separately would involve an awful lot of extra labor, and loss of
valuable space when stacking. As a matter of fact, it involves no extra
labor at all and no extra space. I have had a season’s pack of pulp
amounting to 75,000 5–gal. cans at one plant and cooked in batches of
300 gallons each, stacked each batch separate and it was no trouble at
all. The inspector who examined the tipping and capping job, or the
tipper, if the inspecting was done by him, merely took a fine stiff
brush and a marking pot and marked the batch number on the cap of each
can. This only takes a half minute for a truck load. The date was not
marked on the can, as a record of the batch numbers run on each date
during the season was kept at the office. When the pulp was piled away
each batch was stacked together, and where one batch left off and
another one began a slip of wood was inserted between two of the cans.
On days when the tomatoes are running bad, or there is a scarcity of
help for the sorting belt, it is wise to preserve a sample from each
batch and have an analysis made of it for reference when the pulp is
shipped out. On days when a good grade of tomatoes are being run it is
hardly necessary to analyze every batch, but a sample of about every
third batch can be taken.
Stacking each day’s run separate is, of course, better than no
separation at all. However, there are not many days when the entire run
will have a similar analysis; the best becomes inseparably mixed up with
the worst, and when the pulp is worked up the packer is working in the
dark. To stack a season’s run away without any system of separating
various divisions of it is the worst kind of folly, and is almost sure
to lead to trouble.
How to Stack
When the pulp is stacked away a space of at least an inch should be left
between each can to allow the air to circulate and prevent stack
burning. If this is not done, a pile of pulp may hold the heat for a
week or ten days, and the pulp, particularly that on the inside, will
become brown or even black, due to the long exposure to the heat. The
quicker the pulp can be cooled, the more the bright red color of the
tomato will be retained.
The height to which the pulp is stacked depends upon the heaviness of
the plate of which the can is made, and also, of course, upon the weight
the floor of the warehouse is able to stand. As a rule it is not wise to
pack 5–gal. cans of 107–lb. plate over four high, and not over five high
for cans of 135–lb. plate. Dry, sheltered storage should be provided for
pulp, and it will be found to pay in the end. Exposure to the elements
is very hard on the cans, and alternate freezing and thawing of the pulp
is a great strain on the seams of the can. A comparison of the leaks and
swells on pulp stored in shelter, and that stored in the open, will
convince the packer that it pays to construct dry storage space.
Narrow aisleways should be provided for between the stacked pulp so that
it can be frequently inspected for leaks and swells. By pulling out a
leaker in time, several other cans are prevented from becoming leakers,
as the leaking pulp from one can will run down on several others, and
the pulp, in connection with the oxygen of the air, will eat through the
tin plate, causing rust spots, and then pin holes. Frequent inspection
of the pulp pile and pulling out cans when they are just beginning to
leak or swell will save the packer a lot of money.
Cans should not be stacked on thin boards which will leave the surface
of the can close to the ground, as the moisture of the ground will
quickly rust the tin. It almost seems foolish to mention such a point,
but much pulp is stacked this way and the entire bottom layer when
turned up will be moldy and rusty on one side. The surface of the can
should be at least two inches from the ground. Lacquering will help
some, but will not prevent rusting if the cans are close to the ground.
Processing
Nothing has up to this point been said about the processing of 5–gal.
pulp. Very few packers process their pulp, and many unprocessed packs
have been put up that have not shown over 1 per cent of leaks and swells
where new cans were used and the various manufacturing processes were
carried out as they should be. In many cases a long shipment of such
pulp, after having been stored in a sheltered place for several months,
has produced very few additional swells.
One large packer of pulp has for years given his 5–gal. cans a 30–minute
process in boiling water, having them pass slowly through a boiling
water bath on a chain carrier, the speed of which is regulated so as to
give each can the required time in bath. The cans are placed on the
chain as soon as they are capped and tipped. Although this packer is
very careful in his manufacturing methods he processes as a matter of
insurance, principally because a great deal of his pulp is shipped long
distances. He must figure that it pays him or he wouldn’t keep it up, as
the processing involves quite a little extra handling and extra
equipment, and of course has a tendency to darken the pulp somewhat.
Thirty minutes at boiling temperature is, of course, not sufficient time
to bring the center of the can near the boiling point, but it will
sterilize the can itself and that portion of the pulp which is near the
outside. If the pulp is filled very hot, that portion of it which is in
the center of the can, being the last to cool, should practically
sterilize itself.
Life of Cans
Where a packer puts up pulp in 5–gal. cans for his own use during the
winter months he ought to be able to get two years’ use out of all of
his cans, and three years out of a large percentage of them. It is
questionable whether it is ever advisable to use a can over three
seasons. One reaches a point where the percentage of swells is so large
with old cans that the saving of the cans is unprofitable. When a new
can is first used, the year should be indelibly stamped on the can, so
that at any time the packer can go through his stock of used cans and
tell how many seasons’ use each can has had. This will prove a help in
making a decision on which cans are worth holding over for another
season, and which ones are not. It also gives him a line on the kind of
can that gives him the most value for his money.
Enamel lined cans are now being used a great deal, and as a rule they
seem to give a little better service than the plain tin, although this
is not always the case. Some packers think the enamel imparts a very
slight foreign taste to the pulp, but I have never been able to detect
it. Enameling or lacquering of the outside of the cans is essential if
there is not sufficient sheltered storage for the pulp, or if it must be
stacked in a damp warehouse. An excessive amount of moisture in the air
will quickly start the tin to rusting on plain cans, and many cannery
warerooms are entirely too moist for stacking cans, as they are near the
process room, and the air is often misty with the presence of condensing
steam from the process tanks. If there is ample dry storage space, the
outside enameling of the cans does not seem to be an advantage.
Washing and Drying Cans
When the season’s pack of pulp is being worked up, the cans which are to
be saved for another season’s use should be thoroughly washed out in a
tub with hot water. Spraying devices will not work, as the top of the
can will probably have a layer of pulp stuck to it, due to the receding
of the pulp in the can when it cooled, and even a heavy spray will not
remove all of this. The cans must be partially filled with hot water and
shaken hard to properly clean them. The foreman should inspect the
washed cans at frequent intervals by means of a small electric light
which is wired to a short rod and which can easily be inserted in the
can through the cap hole. If the washing is not thoroughly done this
will show it up quickly.
After as much of the water as possible is shaken out of the cans they
should be put in a drying oven and left over night. In the morning the
cans should be thoroughly dry if sufficient steam is kept in the oven
radiators. The oven is made with a partition which divides it into two
parts, and one part can be filled with the wet cans while the other side
is being emptied of the dry cans.
Protection From Dust
After the cans are dried, a pasteboard insert should be placed in the
cap holes to keep the dust out of them while they are in storage during
the winter and spring. One of the can companies at least, supplies these
pasteboard inserts or inverted caps with their cans, and they fit snugly
into the cap hole.
Testing Used Cans
Before the old cans are used the following year they should all be
tested for pin hole leaks and the leaks patched up. They should then be
re-tested and not used until they are shown to be tight under air
pressure when immersed in water. This can be done during the spring and
summer months, and the packer can then be reasonably sure that his old
cans are in good shape for the next season’s run. If the cans are very
old and the seams are very rusty, new pin holes will be opened up every
time air pressure is put in them. Such cans should, of course, be thrown
away.
Packing 10’s and 1’s
Pulp packed in No. 10 and No. 1 cans is usually filled with a rotary
filling machine, although No. 10’s are often filled from a single line
pipe and the filling can be done quite rapidly where the operator is
expert at the job. If it is necessary to top any of the cans, it should
be done from a small jacketed kettle which is connected up near the
filler, so that the pulp used for topping can be kept hot. The cans
should be put through a can washer and steamer before filling.
No. 1 pulp should have a much larger call from the consumer than it has,
and it could be made very popular if a high standard of quality was set
and maintained, and the advantage of its use advertised to the
housewife. Many consumers who have purchased the small size pulp or
puree for use in making tomato sauce, spaghetti, tomato soup, etc., have
been disappointed in the quality, and after one trial have gone back to
canned tomatoes for these purposes.
For No. 10’s a process in boiling water of 40 minutes in the old style
straight process tank is usually considered sufficient; this is to be
followed by a very gradual cooling in water so that the cans will not
buckle badly. For the No. 1 size a 20–minute process in boiling water is
sufficient. It is always well to cool the cans about ten minutes so they
will not retain the heat a great length of time. A better color and
flavor can be maintained if the goods are cooled in water after
processing. If a continuous agitating cooker is used for processing the
lengths of time given above can be cut down at least 60 per cent.
Packing Barrel Pulp
Barrel pulp is scarcely being packed any more, as the barrel has shown
itself to be unfit for pulp which is packed without preservative. The
use of barrels today is usually only resorted to in emergency cases when
cans for the purpose are not available. If the pulp is to undergo long
storage and shipment, or any great amount of handling, barrel goods will
usually show quite a big loss, not only because much of the pulp is
spoiled so that the spoilage is evident at once upon inspection, but
because of the growth of yeasts and bacteria in the pulp while it has
been in storage, and because of loss of color due to the action of air
seeping into the barrel. Wooden barrels as a rule are not absolutely air
tight, and it is hard to make them so.
I have packed pulp in good uncharred whisky barrels, using 5 lbs. of
salt to the barrel, and rolled the barrels to a sheltered place where
they would not be disturbed until they were ready to open, and after two
or three months’ storage the pulp was all right. If this pulp had been
moved, or held until a spell of warm weather came on, it is doubtful if
it would have shown up so well. The barrels should be washed out well
and steamed for about five minutes before being filled, and the bungs
should be burlapped.
Metal Drums
Ingot iron drums, such as are used for shipping oil, have been
recommended for tomato pulp and I have tried them, but they will not do,
as the tomato acid dissolves too much of the iron.
A Method of Preserving Pulp in Barrels
As a method of preserving pulp in barrels one packer for a number of
years put hydrochloric acid in it. This, being a strong acid, is also
quite a good preservative, and evidently kept the pulp in good shape.
When the pulp was worked up, enough bicarbonate of soda was added to
neutralize this acid, and the result of the neutralization was sodium
chloride, or common salt. There evidently could be no objection made to
this from a pure food standpoint, as none of the acid was left in the
pulp after the neutralization, and sodium chloride is a common
ingredient of pulp. However, the process darkened the pulp, which was an
objection. As to whether or not the flavor was impaired by this
treatment I do not know.