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Sunday, July 07, 2013

Home canning


Do-It-Yourself/Canningom Wikibooks, open books for an open world

 
Introduction

Home canning, also known and bottling, is simple and has been used for preserving foods for many years. With the right equipment and recipes, anyone can begin preserving foods at home.

Care should be taken to follow the recipes and procedures. Botulism is a life threatening bacteria that is commonly associated with improper canning procedures.

Equipment

No matter how you choose to process your food, some things are common elements; tongs that you can use to lift full jars, glass jars, lids, sealing rings. Cooking thermometers, a supply of clean cotton utility towels, and protective clothing such as silicone or leather gloves. Gloves can make handling hot products much easier; a bad grip on a liter jar full of boiling, sticky jam can be dangerous.

Hot Water Bath

A large, enamelled canning boiler with lid rack for jars should set you back no more than $US 40 if you look around. Any large pot should do; just place a metal rack like a cooling rack in the bottom of the pot to provide space under your jars for water to flow.

Pressure Canning

This is the pricier of the options, with a good pressure canner starting at around $US 75-140. Pressurize canning is required for all low acid foods.

Types of Pressure Canners

A pressure canner is not the same as a cooker. Some canners may be used for pressure cooking but a normal pressure cooker should not be used for canning.

Warnings

There are many methods of canning that people have used over time which are proven to be unsafe and even deadly.

Never can foods in the oven, a pot without a lid, microwave, steam canner, dishwasher, or by simply allowing hot jars to seal themselves.

A good seal alone is not enough to protect the contents from developing botulism.

While the oven may reach a suitable temperature, the contents of the jar will not reach a high enough temperature to destroy bacteria.

Stick to the recipes, add vinegar or lemon juice if it says to, and don't add sugar or anything that the recipe does not explicitly say you may.


General Process

There are two approved methods of canning which are fairly similar and use much of the same equipment. The difference between the two is the type of pot you use and how it works.

Before you start, you need to know the altitude in which you live and adjust the approved recipe to ensure you are canning for the right length of time and pressure.

Preparing for either method is the same. Jars, lids and rings should be washed and kept warm until ready to fill with items to be processed. Some people keep their jars in a dishwasher with heat drying to hold them while others keep their jars in a pot of water on low heat. Never place hot foods into a cold jar or place a cold jar into a hot pot, thermal shock can cause the jars to break or even explode.

Lids and rings can be placed into a pan of warm water to simmer on low. Do not boil the lids, just keep them warm to prepare the sealing compound to be accepted by the jar.

Hot Water Bath

Set up the canner and heat water. Canner should be filled about 1/3 full and kept warm, not boiling until you are finished filling it with prepared jars. Set a pot of water on another burner in case you need to add more water after your jars are in place.

Prepare the items that you want to preserve according to an approved recipe. Follow the recipe carefully, changes to ingredients may reduce the amount of acid which could make your recipe unsafe.

Fill jars leaving the appropriate amount of head space for your recipe. Clean rims well, bits of food can prevent lids from sealing. Fit jar with a lid and adjust ring with a fingertip until it stops gently.

Place jars into canner making sure jars are covered by 2 inches of water, if more water is needed add from the extra pot you have heated on another burner.

Place a lid on your pot and process according to the recipe you have chosen. Time begins when the water reaches a full boil.

Open the canner, being careful to prevent steam burns. Remove the jars to a place where they will be undisturbed for at least 8 - 12 hours. Do not adjust rings or tamper with lids.

When jars are cooled, test seals by pressing in center and ensuring that lids don't raise. Remove rings, wash jars, label and put away in a dark cool place until you are ready to enjoy them.

Pressure Canning

If your canner has a dial gauge, the first thing you must do is check it for accuracy. Your local cooperative extension office should be able to do this for you free of charge.

Set up your pressure canner according the instructions included with it. Some canners require more water than others. You do not want the canner to run out of water at any time during the process. If processing is interrupted you will need to start from the beginning.

Prepare your recipe and fill your jars leaving the appropriate head space. Place jars into the canner as you work.

Check lid to make sure vent pipe is clear. Place the lid on the pot, making sure the handles are locked if necessary. Some canners have clamps that screw down while others simply lock by turning the lid.

Next the canner needs to be vented. This is done by adjusting the burner to a fairly high heat and waiting for a strong stream of steam to escape from the vent pipe. This needs to be done for a full 10 minutes. This removes air from the canner so pressure can build with the following step.

Place the regulator or weight onto the valve and wait for the canner to reach the necessary pressure. Use the dial gauge to determine this unless your canner does not have a gauge, then follow the manufacturers instructions. Some regulators need to jiggle several times per minute while others need to rock continuously.

Set your timer when you have reached the correct pressure. Change in pressure at any time can compromise the process, this could result in dangerous, under processed foods.

At the end of timing, turn burner off and wait for canner to depressurize on its own. Do not open or tamper with anything. Removing the regulator too soon or moving the canner can cause liquid from you jars to siphon or even cause the jars to break.

Remove the regulator or weight and wait an additional 10 minutes for the canner to cool.

Open the canner, being careful to prevent steam burns. Remove the jars to a place where they will be undisturbed for at least 8 - 12 hours. Do not adjust rings or tamper with lids. Cooling of jars from a pressure canner can take much longer than those that have been processed in a hot water bath.

When jars are cooled, test seals by pressing in center and ensuring that lids don't raise. Remove rings, wash jars, label and put away in a dark cool place until you are ready to enjoy them.

Recipes

There are many books and websites available with recipes for canning. Be sure to select a recipe that has been approved by the USDA. Recipes that are not tested should be considered dangerous.

The National Center for Home Food Preservation is an excellent source for approved recipes.

Pickling

Pickling is a great option for foods that don't hold up well to the heat and time required by pressure canning. Items like broccoli and cauliflower need to be pressure canned but tend to fall apart and are unappealing. Pickling these items will leave you with a firm, crisp product that is safe because the acid level is high.

Basic picking recipes are a simple syrup made of vinegar, sugar and water.

Jams and Jellies

 Jams, Jellies, Preserves and Butters are a popular way of preserving fruits and some vegetables. Processing times are usually quick and preparation can be quite simple. Sugar is often high but it is an excellent way to add fruit to your diet.

Jams include pectin or a modified starch to allow them to thicken or set to a desired consistency. Preserves and butters are often slow cooked to a thickness much like applesauce and don't use an additional thickener.

Meats

Meats need to be pressure canned every time, there is no approved method of canning meat in a boiling water bath.

Recipes for meats vary greatly. Some people prefer to can just the meat while others like to prepare them as heat and serve meals.

Vegetables

Many vegetables are low acid and need to be pressure canned. The same as with meats, many people like to combine different vegetables as a ready to serve side dish or to be added to soups and stews.

Other Food

There are no safe recipes for certain food items. The USDA has not approved of any recipes for items including: Milk, Cheese, Cream, Eggs, Flour, Starch, Thickening Agents, Grain, Pasta, Rice, Dried Beans, Zucchini, Summer Squash

Items baked in jars should never be stored outside of a freezer or refrigerator.

The entire article can be found at:  http://en.wikibooks.org/wiki/Do-It-Yourself/Canning

Poster's comments:

            None of this is rocket science.

            If in doubt, use the eyeball and smell method when you open up something you've canned. If it doesn't look right, or smell right, don't eat it.

            Lot's of people still do their own home canning, and do just fine.

            Best case, get someone who has done it to show you how, if you can. That is always good for self-confidence.

            Worse case, read about it, and then do it. That usually works well, except for the self-confidence part, or course. In my case, this is what I had to do, and ate it all, and lived just fine. I actually initially cheated and used already clean canned vegetables, and then used them to do my own home canning. And again, I lived.

            Depending on the kind of food one may can at home, one can use acid (like from vinegar or limes), heat (like from a pressure cooker), or even food grade hydrogen peroxide (in the best percentage) just to kill the germs that make the food preservation fail. If in doubt, feed it to your dog, first.

            I still don't know why the term canning is used, since usually it is done in glass jars.

            Last, remember to label the jars with essential information, like what it is, date of preparation, shelf life, etc. You decide what is essential to you.

 

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