WHY CANNED GOODS SPOIL
Every day brings letters to my desk saying, "Why did my jars of
vegetables lose water?" or, "When I looked into my canner I saw all
the beautiful dark sirup in the bottom of the canner instead of in the
jars," or, "What shall I do, my beets are all white?" etc., etc. In
this chapter I am going to try and tell you a few things you must and
must not do. A few "Do's" and "Don'ts" may help you a little in your
canning and food preserving.
I want to say right here that if you have failures do not blame the
method as we are always so apt to do. Experts have worked long enough,
carefully and thoroughly enough, to convince themselves and others
that the cold-pack method and the intermittent method, which methods
are employed for cooking the product in the jar, are sure, safe,
reliable and efficient methods. So if your food spoils convince
yourself it is not the method but something else. Spoilage is due to
imperfect jars, imperfect rubbers, imperfect sealing of tin cans,
careless blanching, insufficient cold dipping or poor sterilizing.
CAN-RUBBERS
Possibly your canning troubles are all due to using a poor grade of
rubber rings. This is poor economy. Rubbers are apt to give more
trouble than anything else to canners when using glass jars. Many of
the rubbers sold are of a very poor quality, disintegrating quickly
when subjected to heat and strain. My sister, canning in the hot
climate of India, has more trouble with the rubber proposition than
anything else.
You want good rubbers, are willing to pay for them, and here is what
you should know about rubber rings.
The one-period, cold-pack method and the intermittent method of home
canning require a rubber ring essentially different from that commonly
used in the old hot-pack method of home canning. Investigation shows
that many of the rings upon the market are unsuitable for these newer
methods, being unable to withstand the long periods of boiling
required in the canning of vegetables and meats.
Practical canning tests have indicated that rubber rings for use in
this method should meet the following requirements:
Inside Diameter. The ring should fit closely, requiring a little
stretching to get it around the neck of the jar. For standard jars the
ring should have an inside diameter of 2¼ inches.
Width of Ring and Flange. The width of the ring or flange may vary
from one-fourth of an inch to twelve thirty-seconds of an inch. Tests
which have been made show that fewer cases of "blow-out" occur when
the flange is ten thirty-seconds of an inch.
Thickness. Rubber rings as found on the market may vary from 1/18 to
1/10 of an inch in thickness. Tests show that 1/12 of an inch in
thickness is sufficient to take up the unevenness in the jar and still
not so thick as to make it difficult to place the cap or adjust the
bail.
Cold-pack and intermittent-canning require a rubber ring that is
tough, does not enlarge perceptibly when heated in water or steam, and
is not forced out of position between the top and the jar by slight
pressure within the jar. This we call a "blow-out."
Rubber rings should be capable of withstanding four hours of
sterilization in boiling water without blowing out on partially sealed
jars, or one hour under ten pounds of steam pressure. They should be
selected with reference to proper inside diameter, width of flange,
and thickness. Good rubber will stretch considerably and return
promptly to place without changing the inside diameter. They should
also be reasonably firm and able to stand without breakage. Color is
given to rings by adding coloring matter during the manufacturing
process. The color of the ring is no index to its usefulness in home
canning. Red, white, black or gray may be used.
Always use _new_ can-rubbers with each year's product of canned goods.
An old rubber may look like a new one but it has lost its elasticity
and its use may cause imperfect sealing and thus endanger the keeping
quality of the food. This is always a hard thing to impress upon
thrifty penny-saving housekeepers. The old rubber looks so good, so
why not use it? But be wise in this and remember it is _never safe to
use old rubbers_. New rubbers are expensive but what about the cost of
the product, the loss of your time and fuel! One jar lost due to an
old rubber is so much food, time and fuel lost.
And do not think yourself thrifty to use two old rubber rings instead
of one, thereby thinking to obtain a better seal, for you will not.
Two old rubbers are inferior in strength to one new good rubber. If
you use old rubbers and your canned goods spoil, blame the rubbers.
GLASS JARS
Next in importance to the rubbers are the glass jars you use. There
are many kinds of fruit jars on the market. The question is frequently
asked, "Which jars on the market are the best." The only answer to
that is to choose the jar which is simplest in construction, which
will seal perfectly and wash easily, which protects the contained food
against contact with metal, which has the fewest parts to lose or
misplace and which fits the shelves and receptacles planned to hold
it.
FLAT SOUR
Flat-sour often causes annoyance to beginners in canning some
vegetables, such as corn, peas, beans and asparagus. These canned
foods may show no signs of spoilage and yet when the can is opened the
product may have a sour taste and a disagreeable odor. This
"flat-sour" is not harmful and must not be confused with "botulinus,"
which is harmful. However, the taste and odor are so disagreeable you
will have no desire to eat "flat-sour" canned goods.
This trouble can be avoided if you will use fresh products, that is,
those which have not been allowed to wilt or stand around the shops
for several days, and will blanch, cold-dip, and pack one jar of
product at a time, and place each jar in the canner as it is packed.
The first jars in will not be affected by the extra cooking. When the
steam-pressure canner is used the jars or cans may be placed in the
retort and the cover placed into position but not clamped down until
the retort is filled.
TROUBLES WITH CORN
Corn seems to give the most trouble, but with a little care and study
this product may be canned as easily as any other grown in the garden.
A little experience in selecting the ears and ability to recognize
corn that is just between the milk and dough stage is important.
Blanch not longer than five minutes. A plunge in cold water is
sufficient. Cut the corn from the cob with a sharp knife and pack at
once in sterilized jars. Best results can be accomplished when two
people cut and one person fills. If it is necessary for one person to
work alone, cut off sufficient corn to fill one jar, pour on _boiling_
water, add salt, place rubber and cap in position and put the jar at
once in the canner. A little overcooking does not injure the quality
of canned corn. Corn should not be tightly packed in the jar; it
expands a little in processing and for this reason each jar should be
filled scant full. Corn that has a cheesy appearance after canning had
reached the dough stage before being packed. Corn should never be
allowed to remain in the cold dip and large quantities should not be
dipped at one time unless sufficient help is available to handle the
product quickly.
Some to be absolutely sure when canning corn, cook it for ten minutes
in hot water before packing into jars.
Leave fully one inch of space at the top when packing corn but enough
water may be poured into the jar to fill the can or jar, for when the
corn swells the water will be absorbed.
Corn Turning Dark. A dark color in canned corn is due to some of
the following causes:
1. Using water that contains too much iron.
2. Using corn that has reached the dough stage.
3. Blanching for too long a period--five minutes is sufficient for
corn.
Water-Logged or Soaked Corn. When canned corn becomes "water-logged"
or "soaked" it is due to such causes as the following:
1. Allowing the product to stand in the cold water too long after the
hot dip.
2. Allowing the jars to stand after they have been packed, and filled
with boiling water. The jars should be immediately placed in the
sterilizer after being packed.
3. Allowing ears of corn to stand in cold water after opening.
4. Heating corn in warm water over a slow fire.
BEETS, THEIR LOSS OF COLOR
The loss of color in canned beets is due to faulty methods of
preparation before packing them into the jars. To secure good results
3 or 4 inches of the top and all of the tail should be left on while
blanching. Beets should be blanched for five minutes and the skin
should be scraped but not peeled. Beets should be packed whole if
possible.
Small beets that run forty to a quart are less likely to fade and are
the most suitable size for first-class packs. The older the beets the
more chance there is for loss of color. Well-canned beets will show a
slight loss of color when removed from the canner, but will brighten
up in a few days.
CLOUDY PEAS
The condition of peas known as "cloudy" is due to such causes as the
following:
1. Cracking the skin of the pea.
2. Blanching for too long a period.
3. Use of water which is too hard or has too much mineral content.
SHRINKAGE OF PRODUCT DURING CANNING
Shrinkage may be due to one or more of the following:
1. Improper blanching and cold-dipping.
2. Careless packing and using variety of sizes.
3. Sterilizing for too long a period.
4. Lack of sizing whole products for the container.
Sometimes there is a natural shrinkage that cannot be prevented. This
is due to the fact that vegetables contain air in their tissues and
when this air is driven off by the heat, the boiling water in the jar
rushes in to fill its place. In consequence we have an apparent
shrinkage in the amount of water. So be careful to do the blanching as
correctly as possible to drive out the air; however, the product will
keep just as well in a jar half full of water as if entirely covered
with liquid. The contents of the jar whether food or air are sterile.
SHRINKAGE OF GREENS
Shrinkage of greens or pot herbs during the canning process is usually
due to insufficient blanching. The proper way to blanch all greens or
pot herbs is in a steamer or in a vessel improvised to do the
blanching in live steam above the water line. If this is not done
much of the mineral salts and volatile oil contents will be extracted
by the water and lost.
LOSS OF LIQUID DURING CANNING
A loss of liquid in canning with a hot-water-bath outfit may be caused
by one or more of the following:
1. Not having the water in the sterilizing vat cover the tops of the
jars by at least one inch.
2. Not providing a suitable platform to hold the jars off the bottom
of the sterilizing vat, permitting circulation of water under as well
as around the jars.
3. Not having the wire bail that goes over the glass tops of jars
sufficiently tight.
REASONS WHY JUICES ARE DRAWN FROM JARS WHEN CANNING WITH STEAM
PRESSURE
1. Open pet cock after pointer or gauge has reached zero; test for
pressure by opening pet cock slowly at first. The gauge does not
register pressure until about one pound of pressure has formed, hence
opening the pet cock before the pointer is at zero means that from one
to two pounds of pressure is being relieved and this will draw the
juices the same as allowing the boiler to stand and a vacuum to form.
2. Allowing the pressure to fluctuate during the time of sterilizing,
such as running the pressure up to fifteen, back to seven or eight and
then up again.
3. Wire bails can be and should be a little tighter when jars are put
in a steam pressure canner. The clamp should be left up as stated.
4. There may be an escape of steam around the seal of the boiler and
this would allow the pressure on the inside of the boiler to
fluctuate.
Any one of those four things will always cause loss of juice.
OPERATION OF HOT-WATER-BATH OUTFIT
These four rules will help in the operation of the hot-water-bath
canning outfit: Example, wash boiler.
1. Support the jars off the bottom sufficiently to permit the
circulation of water under and around the jars.
2. Have the water cover the tops of the jars by at least one inch. The
heat and pressure must be equal on all parts of the jars.
3. Count time as soon as the water begins to _jump_ over the entire
surface. Keep it jumping.
4. Remove jars from the water and tighten the covers as soon as the
time is up.
Rapid cooling of the products prevents overcooking, clarifies the
liquid and preserves the shape and texture.
Operation of steamers or "double-deckers" as they are sometimes
called. These have a small amount of water in a pan below two racks
and the products cook in steam instead of boiling water.
1. Have water boiling in pan when products are put in.
2. Use same time-table as for hot-water bath or wash boiler.
3. Remove jars from steam at the end of the sterilizing period. Do not
allow them to "cool off" in the steamer.
The operation of a water-seal canner is very simple.
1. Jars put on racks and lowered in water as in wash-boiler but due
to an extra jacket the temperature is higher than boiling water.
2. Follow time-table under water-seal.
OPERATION OF STEAM PRESSURE AND PRESSURE COOKER CANNER
1. Place each jar in the canner as soon as it is packed.
2. Have water come up to but not above the platform.
3. Have canner absolutely steam tight.
4. When canner has been filled fasten opposite clamps moderately
tight. When this has been done tighten each clamp fully.
5. Allow pet cock to remain open until live steam blows from it.
6. Close pet cock.
7. Force pressure to the required point before counting time.
8. Maintain a uniform pressure during the sterilizing period.
9. Allow canner to cool before opening pet cock.
10. Have pet cock completely closed during the cooling.
11. Open pet cock before vacuum forms. This is evidenced by a rush of
air into the canner when the pet cock is open. You can test this by
placing the finger over the end of the pet cock. If a vacuum forms it
will draw the flesh of the finger into the opening.
12. Remove jars from canner and tighten lids as soon as canner is
opened.
BREAKAGE OF JARS
When breakage of jars occurs it is due to such causes as these:
1. Overpacking jars. Corn, pumpkin and sweet potatoes swell or expand
in processing. Do not quite fill jars with these products.
2. Placing cold jars in hot water or vice versa. As soon as jars are
filled with hot sirup or hot water, place immediately in the canner.
3. Having the wire bail of glass top jars too tight.
4. In steam canner, having too much water in the canner. The water
should not come above the tray.
5. Cold draft striking the jars when they are removed from the canner.
6. Wire spring too tight, thus breaking jar when contents expand.
MOLD ON CANNED PRODUCTS
Mold may result from one or more of the following:
1. Leaky rubbers or defective joints.
2. Removing tops from the jars at the end of sterilizing period and
substituting new rubbers, without returning the jars to the canning
outfit for at least a few minutes.
3. If the jars are kept in a damp cellar where the rubbers may
decompose, mold may enter through these decomposed rubbers.
ACIDITY OF TOMATOES AFTER CANNING
Too great a degree of acidity in canned tomatoes may be due to
climatic conditions or overripe or underripe product. Such acidity
can be corrected by adding ¼ teaspoonful of baking soda to one quart
of tomatoes.
WATER REQUIREMENTS FOR HOME CANNING
The hardening of beans, peas and some other products after cooking or
processing, or the turning of green vegetables to a dark or russet
color usually indicates that the water contains too high a percentage
of mineral matter. Water used for canning purposes should be pure,
soft if possible or as free from objectionable and excessive qualities
of mineral matter as possible. If you are to can any large quantity of
food products and have difficulty with the water available, it would
be well for you to have the water analyzed and for you to secure the
advice of some one at your college of agriculture.
TOO MUCH SALT IN CANNED GOODS INJURIOUS TO QUALITY
Most vegetables as well as meats are injured in quality by an
excessive use of salt for seasoning in the canning process. A little
salt is very palatable and its use should be encouraged but it is
better to add no salt in canning than to use too much, as it can be
added to suit the taste when served.
ALTITUDE AND ITS EFFECT ON CANNING
Remember that practically all instructions on home canning are based
upon a time schedule for sterilization from sea level to an altitude
of 500 feet above sea level. When canning at an altitude of more than
500 feet above sea level, it will be necessary to use your judgment in
the increase of time for sterilizing on the basis of 20 per cent for
each 4,000 feet.
Blanching means _boiling_, not hot. In different directions for
canning we often find "hot" water mentioned when boiling water is
intended. Water should be _boiling at a gallop_ when vegetables are
blanched--berries and soft fruits are not usually blanched, though
some are scalded to loosen the skin.
BERRIES OR FRUIT RISING TO THE TOP
Some women are disturbed because berries and fruits have a tendency to
always rise to the top of the jar leaving a sirup space in the bottom.
To prevent this you can scald all berries and fruits which are not
ordinarily scalded, for one minute and then cold-dip them. They will
be softened some, but remain firm, and can be packed very closely in a
jar. They can be packed so closely that only a little sirup can be
added. When a jar thus packed comes from the sterilizer the berries or
fruit are not floating as they would be if they were not scalded.
Another method employed to prevent berries from floating is to put the
hot sterilized jar on its side while cooling and to roll it frequently
during the cooling period. The berries are then evenly distributed
through the sirup.
In canning mushrooms in tin, always use lacquered cans. Do not fail to
blanch and cold dip before packing, and remove the mushrooms
immediately after opening the tin cans.
In canning cabbage and other similar products always soak the product
in cold brine for one hour before sterilizing. Use ½ pound salt to 12
quarts water. This is believed to improve the flavor. Always wash
greens or other vegetables, to remove all dirt and grit.
TROUBLES WITH TIN CANS
To discover pin-holes or any leaks in a tin can, immerse it in boiling
water after sealing and if there is any bubbling from the can, you may
rest assured it needs resealing.
Swells in tin cans are caused by insufficient sterilization. The
action of bacteria causes gas to form in the can and as a result there
is a bulging at either end. If left alone long enough the cans will
explode. Watch carefully all bulging cans and use them first.
Sometimes a slight bulge occurs when a can has been filled too full.
If you have trouble sealing tin cans the chances are that the can is
too full. See that no particle of food touches the top or when
soldering, if you employ that method of sealing, small pin holes will
be blown in the seal by escaping steam which is generated by the hot
sealer coming in contact with the cold food. Another cause of sealing
trouble lies sometimes in a poorly heated capping steel or because it
is not kept brightly tinned. To make a proper seal the steel must be
kept bright, hot and clean.
Also, be sure you buy good solder as there are inferior grades that
are too poor to flow when properly heated.
FROZEN PRODUCTS
Watch all jars and cans that have been subjected to a freeze. If the
cans or jars do not burst the only harm done is a slight softening of
the food tissues. In glass jars after freezing there is sometimes a
small crack left which will admit air and consequently bacteria.
Sometimes cans and jars tip over in the wash boiler during
sterilizing. This is caused by using a false-bottom which is too low
or because it is not well perforated. Or it may be due to the fact
that the jar was not well packed and so may be too light in weight.