CHAPTER IX
EASY METHODS OF CANNING IN TIN
If the proper sanitary requirements are provided and instructions of the cold-pack method of canning are followed, it is entirely safe and practical to use tin cans for all kinds of fruits, vegetables and other food products. Food poisoning—commonly called ptomaine poisoning—and the effects ascribed to "salts of tin" result from improper handling and improper preparation of the product before packing, or from allowing the product to stand in the tin after it has been opened. The raw food products used for canning in tin must be in sound condition, just as they must be if put into glass containers.
It is true that canned foods may be rendered unfit for use by improper handling of the product before packing and that decomposition may occur after canning, owing to insufficient processing, improper sealing or the use of leaky containers. This condition, however, is no more likely to be encountered in foods put up in tin than in products canned in other types of containers. You run no more danger of poison from your own tin-canned products than from tin-canned food bought at the store. Most canned foods if in a spoiled condition readily show this condition by the swelling of the can or by odor or taste. Canned foods showing such evidences of decomposition should not be used.
Certain foods which are high in protein, such as meats, peas, beans and fish products, may undergo decomposition without making this condition obvious to the senses. It is essential, therefore, that the greatest care be taken to subject such products to proper preparation and ample processing. It should be remembered that canned foods, after opening the containers, should be treated as perishable products and should be handled with the same precautions that are applied when fresh products are being used.
ADVANTAGES OF CANS
Many housewives ask, "Why can in tin when we have always used glass jars?" There are many advantages in canning in tin which we can well consider. There is no breakage as in glass; you can handle the tin cans as carelessly as you choose and you will not hear a snap or crack indicating a lost jar. Furthermore, tin cans are easier to handle not only in canning but in storing.
The expense each year of new tin covers or new tin cans is no more than the purchase of new rubbers and the replacement of broken glass jars. Furthermore, one big advantage of tin over glass is that tin cans can be cooled quickly by plunging them into cold water immediately upon removal from the canner, and thus the cooking is stopped at the proper moment. The product is consequently better in form and flavor than when the cooking is prolonged, as it must be in glass jars. Many women like the large openings of cans because they can make better packs than when using narrow-necked jars.
If you do not care to bother with the soldering you can purchase a safe and simple device that will do the work for you. This device is called a tin-can sealer. With a sealer no soldering is necessary. Even an inexperienced person, by following directions carefully, can seal a can as well as an experienced one. The sealed cans look exactly like those purchased at the store. Two or three cans a minute can be sealed with this device.
This is the way to operate a can sealer: Prepare the fruits and vegetables as for any canning, following directions formerly given for cold-pack canning.
After the fruits or vegetables have been properly prepared, blanched and cold-dipped if necessary, place them in sanitary, solderless cans. Put water or sirup on, according to directions. Put the top on the can and place the can in the sealer.
Raise the can into the chunk by swinging the raising lever at the bottom of the machine against the frame. Turn the crank, rapidly at first, with the right hand, and at the same time push the seaming-roll lever very slowly with the left hand until it will go no farther. This is one of the most important steps in the use of the machine. Continue to give the crank several turns after the seaming-roll lever has gone as far as it will go. This completes the first operation or seam.
Continue turning the crank with the right hand, and with the left hand pull the seaming-roll lever until it will go no farther in this direction. After this has been done give the crank several more turns, and the second and final operation is complete. Bring the seaming-roll lever back to the middle position and remove the can. The can is then ready for sterilization.
Before sealing a new lot of cans or after changing for a different size of can, one or two of the cans about to be used should be tested for leaks. If this is done and the cans stand the test it will be unnecessary to test the remaining cans of that same lot. The following is a simple and safe test:
Put one tablespoon of water into an empty can and seal. Have on hand a vessel containing enough boiling water to cover the can. Set aside and, as soon as bubbles disappear from the surface, immerse the can in the hot water. This heats the water in the can and creates a pressure within the can. Keep the can under the surface for two minutes, and if by that time no bubbles rise from the can the can has been sealed air-tight.
ADJUSTING THE SEAMING ROLLS
If bubbles rise from the can the seam is not sufficiently tight. If this seam is not sufficiently tight the second seaming roll needs adjusting, provided the directions regarding seaming rolls given below have been observed. To set the rolls proceed as follows: Loosen the nut on the bottom of the seaming-roll pin. With a screw driver turn the seaming-roll pin counter clockwise—that is, from right to left. Turn very slightly and, while holding the seaming-roll pin with the screw driver in the left hand, tighten nut with the right hand, and test as before.
Occasionally it is well to compare the seam after the first operation with the sample can which is sent with the machine.
If seaming rolls cut into the can they are set too close, and the seaming-roll pin should be adjusted in the opposite direction from above.
After adjusting, always test cans as suggested above before canning. The seaming rolls are set before the machine leaves the factory and should not require adjusting for some time, but I have found that slight variations in cans may make adjusting necessary.
If for any reason the second seaming roll is brought into contact with the can before the first operation is complete it may injure the can seriously, thus preventing an air-tight seam.
If the first seaming roll is forced in too rapidly it may ruin the seam. Push the seaming-roll lever gently and steadily, while turning the crank with the right hand. This rolls the seam gradually. There is no danger from bringing in the second seaming roll too quickly if the first seaming roll has completed its work.
There are thus, as you see, two kinds of tin cans used in home canning: The sanitary or rim-seal can, which is used with a sealer, and the cap-and-hole can. The latter consists of a can, and a cover which carries a rim of solder and is fastened on the can by the application of heat.
The sanitary can has a cover a trifle larger than the diameter of the can, thus leaving the full diameter of the can open for filling. That part of the cover that comes into contact with the can is coated with a compound or fitted with a paper gasket or ring which makes a perfect seal when the cover is crimped on the can. Some mechanical device is necessary for sealing this can, and this is the sealer.
Cans may be had with inside enamel or plain without any enamel. The following fruits and vegetables should be canned in enamel-lined cans: All berry fruits, cherries, plums, rhubarb, pumpkin, beets and squash. All highly colored products should be canned in enamel-lined cans to prevent the bleaching effect induced by their action upon the plain tin. Some prefer to can fish and meat in the enamel-lined cans. Other products not mentioned here may be canned in plain cans, since they are less expensive than the enamel-lined cans.
Covers are lined in two ways, with the paper gasket and the compound gasket. The compound gasket is merely a preparation, scarcely visible, applied to the under side of the cover and is not easily damaged by handling. The paper gasket is a ring placed on the under side of the cover and must be handled carefully. If the paper gasket becomes broken the cover must be discarded. To sterilize covers having the paper gasket, place them in the oven for a few minutes, but do not wet them, before sealing cans. Do not remove or handle paper gaskets.
When the cans are removed from the cooker the ends should be raised; this is caused by the pressure within. If they are not raised at the ends the cans should be carefully examined for defects. After the cans are sterilized they should be cooled off in water. This will cause the ends to collapse. If they do not collapse the reason is probably due to overfilling. It must be remembered that peas, beans and corn swell a certain amount after water is placed in the cans; therefore, in canning these vegetables the cans should be filled only to within a quarter of an inch of the top. If the pressure of the air from without will not cause the end to collapse, it should be forced in by hand.
THE TINNING OUTFIT
Tin-can sealers are made to handle the regular Number 2, or pint cans, and the Number 3, or quart cans. The sizes are interchangeable, so that in a few minutes' time a Number 2 machine may be changed into a Number 3 machine with the necessary attachments. So it is economy to buy a machine with these attachments, as you can then use either pints or quarts as you desire.
If you are selling to boarding houses and hotels you also will want half-gallon and gallon cans. If you use these larger-size cans and want the sealer you can get it for these sizes, but you must tell exactly what you want when ordering.
The prices which I give are 1919 prices and are of course not stationary. A sealer that will seal the Number 2 sanitary tin cans costs $14. A sealer for Number 3 cans will cost the same amount. But the ideal arrangement is the combination machine which can be used for both the pints, Number 2, and the quarts, Number 3. This type of sealer costs $16.50. A special machine is used for sealing the Number 10 or gallon cans, and its price is $35.
The price of the "winter can opener" is $17.00 for smaller size and $19.50 for the larger one.
Several standard sizes of tin cans are in common use for canning purposes, as follows:
| NUMBER | SIZE INCHES | DIAMETER OF OPENING INCHES |
| 1 | 2⅝ by 4 | 2-1/16 |
| 2 | 3-5/16 by 4-9/16 | 2-1/16 or 2-7/16 |
| 3 | 4⅛ by 4⅞ | 2-1/16 or 2-7/16 |
| 10 | 6-3/16 by 6⅞ | 2-1/16 or 2-7/16 |
The cans are put up in crates holding 100 or 500 cans. If you are canning for the ordinary market use Number 2 cans for berries, corn, peas and cherries; Number 3 cans for tomatoes, peaches, apples, pears and sweet potatoes.
In buying cans it is always necessary to state whether you desire plain tin or lacquered—enameled—cans. In buying caps always ask for the solder-hemmed caps and give the diameter of the can opening. For whole fruits and vegetables, cans with two-and-seven-sixteenth-inch or even larger openings are preferable. Since the size of the can opening varies and it ordinarily will not be advisable to have more than one capping iron, it is recommended that the larger size—two-and-seven-sixteenth-inch—capping iron be purchased.
The tin cans come in lots of 100 or 500 cans. It is possible to buy as few as two dozen cans, but that never pays. It is cheaper to buy a larger quantity. Number 2 plain sanitary cans in 500 lots cost $3.45 a hundred; in 100 lots, $3.65 a hundred. Number 2 sanitary cans—enameled—in 500 lots cost $3.80 a hundred; in 100 lots, $3.95 a hundred. Number 3, plain, in 500 lots are $4.50 a hundred; Number 3, plain, in 100 lots are $4.70 a hundred. Number 3, enameled cans, in 500 lots, are $4.95 a hundred; Number 3, enameled cans, in 100 lots, are $5.10 a hundred.
The gallons come twelve cans to a case. They are $1.40 a dozen if 100 cases are bought. If less than 100 cases are ordered they are $1.50 a dozen.
The cans that you have to solder yourself run just about the same price, Number 2 being $3.60 in 500 lots and $3.80 in 100 lots. Number 3 are $4.70 in 500 lots and $4.90 in 100 lots. The buyer must pay express or freight charges on both sealers and tin cans.
PREPARING OLD CANS FOR REFILLING
Formerly, after using a tin can once we threw it away; but men with brains, realizing this waste, have come to our rescue, and as a consequence we can now use a can three times—that is, if we have a sealer. The sealer that seals our cans will also open them for us, so it becomes our winter can opener. With this can opener we can use our tin cans three times, buying each year only new tops, which cost less than good rubbers.
Cutting and Reflanging Tin Cans. Cutting off the can the first time. First lift the spring pin in the top piece, push the lever from you, drop the spring pin between the stop of the first operation roll and the cutting-roll stop. Place the can in the sealer, push the can-raising lever against opposite side of frame. Turn the crank and gently push seaming-roll handle from you until you come against cutting-roll stop, and the top of your can is cut off.
Reflanging. Remove standard can base and in its place put in the reflanging base, lift the spring-pin and bring seaming-roll lever to the original position. Drop the spring pin between the stops of the first and second operation rollers, place the can in the sealer, open end down, push raising lever round until the can engages with the chuck, turn the crank and at the same time gradually push raising lever round against the frame. The can is now ready for use again.
Resealing. The can is now three-sixteenths of an inch shorter than originally. Remove the reflanging base, put one of the narrow washers on the top of the can-raising lever, then the standard can base, and the sealer is now ready. Proceed as with the original can.
Cutting the Can the Second Time. Proceed as at the first time, only be sure to cut off the opposite end. The can may be cut open and reflanged only twice, once on each end of the can body. In cutting and reflanging the second time, leave the three-sixteenth-inch washer under the can base and reflanging base.
Resealing the Second Time. Remove reflanging base and put the second three-sixteenth-inch washer under the standard can base and proceed as directed under resealing.
THE SOLDERING OUTFIT
The soldering equipment required includes a capping iron, a tipping copper, soldering flux, a small brush, a porcelain, glass or stoneware cup in which to keep the soldering flux: sal ammoniac, a few scraps of zinc, solder, a soft brick and a file.
Soldering Flux. Soldering flux is a solution of zinc in crude muriatic acid. It is used for cleaning the irons and for brushing the tins and lead surfaces so as to make it possible for the melted lead to adhere to the tin.
To Make the Flux. Purchase at the drug store ten cents' worth of crude muriatic acid. Place this in a porcelain, stone or glass jar. Add as much zinc in small pieces as the acid will thoroughly dissolve. The flux is always best when it has stood from twelve to sixteen hours before using. Strain through a piece of cloth or muslin. Dilute with a little water, about half and half. This will make the soldering flux. When using keep the flux well mixed and free from dust and dirt.
Tinning Capping Iron. Purchase five or ten cents worth of sal ammoniac at the drug store; clean iron with file or knife. Mix a little solder with the sal ammoniac. Heat the capping iron hot enough so that it will melt the solder and convert it into a liquid. Place the iron in the vessel containing the mixture of sal ammoniac and solder. Rotate iron in the mixture until the soldering edge of the iron has become bright or thoroughly covered with the solder. All particles of smudge, burned material, and so forth, should be removed from the iron before tinning.
Tinning the Tipping Copper. The tipping copper is tinned in very much the same way as the iron. Sometimes it is desirable to file the tipping copper a bit so as to make it smooth and to correct the point. Heat the copper and rotate the tip of it in the mixture of sal ammoniac and lead until it has been covered with the melted lead and is bright as silver. The copper should be filed nearly to a sharp point.
Capping a Tin Can. Use one tin can for experimenting. By capping and tipping, heating the cap, and throwing it off and simply putting another cap on the same can, you can use this one can until you become proficient in capping.
When capping the full packs arrange the cans in rows upon the table while the capping and tipping irons are heating in the fire. Take a handful of solder-hemmed caps and place them on all cans ready to be capped. Place a finger on the vent hole, hold cap in place, and run the brush containing a small amount of flux evenly round the solder-hemmed cap with one stroke of the hand. Do this with all cans ready to be capped. Then take the capping iron from the fire. Insert in center the upright steel. Hold the capping iron above the cap until the center rod touches the cap and holds it in place. Then bring it down in contact with all four points of solder-hemmed cap and rotate back and forth about three strokes. Do not bear down on capping iron. A forward and back stroke of this kind, if properly applied, will perfectly solder the cap in place. Remove capping iron and inspect the joint.
If any pin-holes are found recap or repair with copper. It may be necessary to use a piece of wire lead or waste lead rim from a cap to add more lead to the broken or pinhole places of a cap.
Tipping a Tin Can. Take flux jar and brush. Dip brush lightly in flux and strike the vent hole a side stroke, lightly, with brush saturated with flux.
Use the waste solder-hemmed cap rim or wire solder. Place point of wire solder over vent hole. Place upon this the point of the hot, bright, tipping copper. Press down with a rotary motion. Remove quickly. A little practice will not only make this easy, but a smooth, perfect joint and filling will be the result. The cans are now ready for the canner. The handwork is all over, for the canner will do the rest.
Precautions. Do not fill tin cans too full. Leave a one-eighth to one-quarter inch space at the top of the can and see that the product does not touch the cover. If any of the product touches the cover the application of the hot iron produces steam, which may blow out the solder, making it impossible to seal the can.
RULES FOR STERILIZING
Remember all fruits and vegetables are prepared for tin cans exactly as they are for glass jars and the period of cooking or sterilizing is the same. The following rules will help to avoid difficulties in the operation of the various canning outfits:
For hot-water-bath outfits, whether homemade or commercial.
1. Support the cans off the bottom sufficiently to permit the circulation of water under and round the cans.
2. Have the water cover the tops of the cans by at least one inch. The heat and pressure must be equal on all parts of the cans.
3. Count time as soon as the water begins to jump over the entire surface. Keep it jumping.
4. On removing the cans throw them into a sink with running cold water or plunge them into a pail of cold water.
5. If the cans are laid on their sides the false bottom is not necessary.
For steam-pressure and pressure-cooker canners the following precautions should be observed:
1. Lower the inside crate until it rests on the bottom of the steam-pressure canners. In the case of the pressure cooker put the rack in the bottom of the cooker.
2. Have the water come to, but not above, the platform.
3. Tin cans can be piled one above the other.
4. When the canner has been filled fasten the opposite clamps moderately tight. When this has been done tighten each clamp fully.
5. Have the canner absolutely steam-tight.
6. Allow the pet cock to remain open until live steam blows from it.
7. Close the pet cock.
8. After the gauge registers the correct amount of pressure, begin counting the time.
9. Maintain a uniform pressure throughout the process.
10. When the process is completed allow the steam to escape gradually through the pet cock. You can lift the pet cock slowly, using a pencil or a knife. This can be done only with tin cans. If glass jars are used the canner must be cooled before opening the pet cock. Blowing the steam from the pet cock is likely to cause a loss of liquid from the partly sealed glass jars.
11. Throw the tin cans into cold water.
12. If tin cans bulge at both ends after they have been completely cooled, it indicates that they are spoiling and developing gas, due to bacteria spores or chemical action. These may be saved if opened at once and resealed or resoldered and processed again for ten minutes.
The following table will help you in estimating how many cans of fruit and vegetables you will obtain from a bushel of product:
NUMBER OF CANS A BUSHEL FILLS
| NO. 2 CANS | NO. 3 CANS | |
| Windfall apples | 30 | 20 |
| Standard peaches | 25 | 18 |
| Pears | 45 | 30 |
| Plums | 45 | 30 |
| Blackberries | 50 | 30 |
| Windfall oranges, sliced | 22 | 15 |
| Windfall oranges, whole | 35 | 22 |
| Tomatoes | 22 | 15 |
| Shelled Lima beans | 50 | 30 |
| String beans | 30 | 20 |
| Sweet corn | 45 | 25 |
| Peas, shelled | 16 | 10 |