Mold
Mold is a fungus with dry spores. Poorly sealed jars of high-acid or pickled foods are perfect locations for these spores to set up housekeeping. After the spores float through the air and settle on one of their favorite foods, they start growing. At first you see what looks like silken threads, then streaks of color, and finally fuzz, which covers the food. Processing high-acid and pickled food in a water-bath canner destroys mold spores.
Don’t eat food that’s had fuzz scraped off of it. This was thought safe at one time but not anymore. Mold contains carcinogens that filter into the remaining food. Although the food appears to be noninfected, ingesting this food can cause illness.
Yeast
Yeast spores grow on food like mold spores. They’re particularly fond of high-acid food that contains lots of sugar, like jam or jelly. They grow as a dry film on the surface of your food. Prevent yeast spores from fermenting in your food by destroying them in a water-bath canner.
Bacteria
Bacteria are a large group of single-celled microorganisms. Common bacteria are staphylococcus and salmonella. Botulism, the one to be most concerned with in canning, is the most dangerous form of bacteria and can be deadly. It’s almost undetectable because it’s odorless and colorless. Botulism spores are stubborn and difficult to destroy.
Botulism spores hate high-acid and pickled foods, but they love low-acid foods. When you provide these spores with an airless environment containing low-acid food, like a jar of green beans, the spores produce a toxin in the food that can kill anyone who eats it. The only way to destroy them in low-acid food is by pressure canning.
For safety’s sake, before eating any home-canned, low-acid food, boil it for 15 minutes from the point of boiling at altitudes of 1,000 feet or lower. For altitudes above 1,000 feet, add 1 additional minute for each 1,000 feet of elevation.
Boiling does not kill the botalism bacteria. Symptoms from ingesting botulism-infected food occur within 12 to 36 hours after eating it. Symptoms include double vision and difficulty swallowing, breathing, and speaking. Seek medical attention immediately if you believe you’ve eaten infected food. Antitoxins are available to treat this poisoning, but the sooner, the better.
Enzymes
Enzymes are proteins that occur naturally in plants and animals. They encourage growth and ripening in food, which affects the flavor, color, texture, and nutritional value. Enzymes are more active in temperatures of 85 to 120 degrees than they are at colder temperatures. They’re not harmful, but they can make your food overripe and unattractive while opening the door for other microorganisms or bacteria.
An example of enzymes in action occurs when you cut or peel an apple. After a few minutes, the apple starts to brown. Stop this browning by treating the cut apple with an antioxidant solution (see Chapter 5). Other methods for halting the enzymatic action in your food are blanching and hot packing.
Adjusting your altitude
Properly processing your home-canned foods destroys microorganisms. Knowing your altitude is important because the boiling point of water and pressure in a pressure canner changes at altitudes over 1,000 feet above sea level. This occurs because the air is thinner at higher elevations. With less air resistance, water boils at a temperature below 212 degrees.
To produce food free from microorganisms at higher elevations, adjust your processing time and pressure to compensate for your altitude. Use the altitude adjustment charts in Chapter 4 (for water-bath canning) and in Chapter 9 (for pressure canning). These adjustments ensure that your food is heated to the correct temperature for destroying microorganisms.
If you don’t know the elevation of your city, check with your city offices, your public library, or your state or county cooperative extension service listed in your local telephone directory. Or check out http://national4-hheadquarters.gov/extension/index.html on the Internet. Just enter your city and state in the box at the bottom of the page, click Submit, and scroll down to find the elevation of your city.
Detecting Spoiled Foods
No one can’t promise you that your home-canned foods will always be free from spoilage, but you can rest assured that your chances for spoiled food are greatly reduced when you follow the precise guidelines for each preserving method. If you suspect, for any reason, that your food is spoiled or just isn’t right, don’t taste it. Also, just because your food doesn’t look spoiled, doesn’t mean that it’s not.
The best way to detect food spoilage is by visually examining your jars. Review the following checklist. If you can answer “true” for each of the following statements, your food should be safe for eating:
The food in the jar is covered with liquid, is fully packed, and has maintained the proper headspace.
The food in the jar is free from moving air bubbles.
The jars have good, tight seals.
The food has maintained a uniform color.
The food isn’t broken or mushy.
The liquid in the jar is clear, not cloudy, and free of sediment.
After your food has passed the previous checklist, examine your jars more closely. If you discover any spoilage during any step of this process, don’t continue your search, but properly dispose of your product.
1. Hold the jar at eye level.
2. Turn and rotate the jar, looking for any seepage or oozing from under the lid that indicates a broken seal.
3. Examine the food surface for any streaks of dried food originating at the top of the jar.
4. Check the contents for any rising air bubbles or unnatural color.
The food and liquid should be clear, not cloudy.
5. Open the jar.
There shouldn’t be any spurting liquid.
6. Smell the contents of the jar.
Take note of any unnatural or unusual odors.
7. Look for any cottonlike growth, usually white, blue, black, or green, on the top of your food surface or on the underside of the lid.
Spoiled low-acid food may exhibit little or no visual evidence of spoilage. Treat any jars that are suspect as if they contained botulism toxins. Follow the detailed instructions for responsibly disposing of spoiled, low-acid food in Chapter 9. Never use or taste any canned food that exhibits signs of spoilage or that you suspect is spoiled.
Removing the screw bands from your cooled, sealed jars before storing them allows you to easily detect any broken seals or food oozing out from under the lid that indicates spoilage.
Part II
Water-bath Canning
In this part . . .
This part tells you all you need to know about the most popular method of canning: water-bath canning. Some of the products, like jam, jelly, marmalade, relish, and salsa may be familiar to you, while others, like chutney, conserves, and pickled vegetables, may be new. Packed with easy-to-follow instructions for canning a wide variety of fruits, jellies, and more, this part sends you well on your way to a pantry stocked with healthy and delicious items.
Chapter 4
Come On In, the Water’s Fine! Water-bath Canning
In This Chapter
Discovering water-bath canning
Recognizing high-acid foods
Stepping up to high-altitude canning
Knowing the proper processing procedures
With water-bath canning you essentially use a special kettle to boil filled jars for a certain amount of time. Common foods for water-bath canning include fruits and tomatoes, as well as jams, jellies, marmalades, chutneys, relishes, pickled vegetables, and other condiments.
You’re probably wondering whether water-bath canning is safe for canning food at home. Rest assured: The answer is a most definite “Yes!” — provided that you follow the instructions and guidelines for safe canning.
In this chapter, you discover which foods are safely processed in a water-bath canner and step-by-step instructions for completing the canning process. In no time, you’ll be turning out sparkling jars full of homemade delicacies to dazzle and
satisfy your family and friends.
Water-bath Canning in a Nutshell
Water-bath canning, sometimes referred to as the boiling-water method, is the simplest and easiest method for preserving high-acid food, primarily fruit, tomatoes, and pickled vegetables.
To water-bath can, you place your prepared jars in the a water-bath canner, a kettle especially designed for this canning method (see the section “Key equipment for water-bath canning” for more on the canner and other necessary equipment); bring the water to a boil; and then maintain that boil for a certain number of minutes, determined by the type of food and the size of the jar. Keeping the water boiling in your jar-filled kettle throughout the processing period maintains a water temperature of 212 degrees. This constant temperature is critical for destroying mold, yeast, enzymes, and bacteria that occur in high-acid foods.
Water-bath canning is one of the two recommended methods for safely home-canning food (the other method is pressure canning, covered in Chapter 9). Although each processing method uses different equipment and techniques, the goal is the same: to destroy any active bacteria and microorganisms in your food, making it safe for consumption at a later time. This is accomplished by raising the temperature of the food in the jars and creating a vacuum seal.
Water-bath canning and pressure-canning methods aren’t interchangeable because the temperature of a water bath only reaches 212 degrees while the temperature of a pressure canner reaches 240 degrees, the temperature necessary to safely process low-acid foods. For more on pressure canning, go to Chapter 9.
Foods you can safely water-bath can
You can safely water-bath can only high-acid foods — those with a pH factor (the measure of acidity) of 4.6 or lower. So just what is a high-acid food? Either of the following:
Foods that are naturally high in acid: These foods include most fruits.
Low-acid foods that you add acid to, thus converting them into a high-acid food. Pickled vegetables fall into this category, making them safe for water-bath canning. You may change the acid level in low-acid foods by adding an acid, such as vinegar, lemon juice, or citric acid, a white powder extracted from the juice of acidic fruits such as lemons, limes, or pineapples. Some examples of altered low-acid foods are pickles made from cucumbers, relish made from zucchini or summer squash, and green beans flavored with dill. Today, tomatoes tend to fall into this category. They can be water-bath canned, but for safety’s sake you add a form of acid to them.
If your recipe doesn’t tell you which processing method (water-bath canning or pressure canning) is appropriate for your food, don’t guess. Instead, use litmus paper to test the pH level of your food (see Chapter 3). If your food has a pH of 4.6 or lower, use the water-bath canning method; if it has a pH of 4.7 or higher, use the pressure-canning method.
Key equipment for water-bath canning
Just as you wouldn’t alter the ingredients in a recipe or skip a step in the canning process, you don’t want to use the wrong equipment when you’re home-canning. This equipment allows you to handle and process your filled jars safely.
The equipment for water-bath canning is less expensive than the equipment for pressure canning (check out Chapter 9 to see what equipment pressure canning requires). Water-bath canning kettles cost anywhere from $25 to $45. In some instances, you may purchase a “starter kit” that includes the canning kettle, the jar rack, a jar lifter, a wide-mouth funnel, and jars for about $50 to $60. (If you don’t have a supplier near you, check out Chapter 22.)
Following is a list of the equipment you must have on hand, no exceptions or substitutions, for safe and successful water-bath canning:
A water-bath canner: The water-bath canner consists of a large kettle, usually made of porcelain-coated steel or aluminum, that holds a maximum of 21 to 22 quarts of water, has a fitted lid, and uses a rack (see the next item) to hold the jars (see Figure 4-1). Do not substitute a large stock pot for a water-bath canner. It is important for the jars to be sitting off the bottom of the canner, and there are racks that fit this purpose, included in your canner kit.
Although aluminum is a reactive metal (a metal that transfers flavor to food coming in direct contact with it), it’s permitted for a water-bath canner because your sealed jar protects the food from directly touching the aluminum.
Figure 4-1: A water-bath canning kettle with the rack hanging on the edge of the kettle.
A jar rack: The jar rack for a water-bath canner is usually made of stainless steel and rests on the bottom of your canning kettle. It keeps your jars from touching the bottom of the kettle, or each other, while holding the filled jars upright during the water-bath processing period. The rack has lifting handles for hanging it on the inside edge of your canning kettle (refer to Figure 4-1), allowing you to safely transfer your filled jars into and out of your kettle.
Canning jars: Canning jars are the only jars recommended for home-canning. Use the jar size recommended in your recipe. For more on canning jars, refer to Chapter 2.
Two-piece caps (lids and screw bands): These lids and screw bands, explained in detail in Chapter 2, create a vacuum seal after the water-bath processing period, preserving the contents of the jar for use at a later time. This seal protects your food from the reentry of microorganisms.
The older-style rubber rings are no longer recommended. Although they are sometimes still available secondhand, the seal is no longer dependable enough to result in a safe product. You can find these rubber rings in some specialty canning stores; however, due to their novelty, they are very expensive and sold in small quantities. Reserve this type of canning jar and kitschy design for your fun food gifts, not canning for a family’s pantry.
In addition to the must-have items listed in the preceding, you may also want the following things. These items aren’t critical to the outcome of your product, but you’ll discover a more streamlined, efficient level of work if you use them (you can find out more about these and other helpful but not necessary tools in Chapter 2):
A teakettle or saucepan filled with boiling water to use as a reserve.
A ladle and wide-mouth funnel to make transferring food into your jars easier. The funnel also keeps the rims of the jars clean, for a better seal.
A lid wand so that you can transfer your lids from the hot water to the jars without touching them and a jar lifter so that you can safely and easily lift canning jars in and out of your canning kettle.
A thin plastic spatula to use for releasing air bubbles in the jar.
The Road to Your Finished Product
Every aspect of the canning procedure is important, so don’t skip anything, no matter how trivial it seems. When your food and canning techniques are in perfect harmony and balance, you’ll have a safely processed product for use at a later time.
The following sections guide you through the step-by-step process for creating delicious, high-quality, homemade treats for your family and friends.
Always practice proper kitchen sanitation and cleanliness, carefully handle your food, and follow your recipe to the letter. Don’t alter your recipe or skip any processing step.
Step 1: Getting your equipment ready
The first thing you do when canning is to inspect your equipment and get everything ready so that when you’re done preparing the food (Step 2 in the canning process), you can fill your jars immediately.
Inspect your jars, lids, and screw bands
Always review the manufacturer’s instructions for readying your jars, lids, and screw bands. Then inspect your jars, lids, and screw bands for any defects as follows:
Jars: Check the jar edges for any nicks, chips, or cracks in the glass, discarding any jars with these defects. If you’re reusing jars, clean any stains or food residue from them and then recheck them for any defects.
Screw bands: Make sure the bands aren’t warped, corroded, or rusted. Test the roundness of the band by screwing it onto a jar. If it tightens down smoothly without resistance, it’s useable. Discard any
bands that are defective or out of round (bent or not completely round).
You can reuse screw bands over and over, as long as they’re in good condition. And because you remove them after your jars have cooled, you don’t need as many bands as jars.
Lids: All lids must be new. Lids aren’t reusable. Check the sealant on the underside of each lid for evenness. Don’t use scratched or dented lids. Defective lids won’t produce a vacuum seal. Don’t buy old lids from secondhand stores. Older lids will not seal properly.
Canning and Preserving For Dummies Page 6