Preserving Your Harvets Part II: Canning

In this post, I explain some basics of canning.  If you are considering caning for the first time, this post will save you time doing research and give you a "quick start" guide to the process.

This is the first year that I've done caning at home and began the process with a sense of fear and dread.

Unlike freezing with which everyone has some experience due to the universal presence of the refrigerator, canning is a process that is a bit of a lost art for many of us; grandma canned, but her knowledge and skill wasn't transmitted to the next generation.  As a result, many of us have only fearful thoughts of canning (messing up and getting botulism or being scalded by hot steam, or exploding pressure caners etc.)

Well put your fears to rest.  It's not that hard or scary.  If I can do it, you can as well.  So here's the information you need to get you started.

The Hot Water Bath Process

This is the easiest and requires the least equipment.  It is generally used for preserving fruit, jams and jellies, tomatoes and pickles.  You can preserve a lot with the hot water bath method, but not everything (I elaborate on this below)

To can using the "hot water bath" method:

• Wash your vegetables and do the basic food preparation.  The prep. will vary depending on the vegetable or fruit you are preserving.  (For example, if you want to can tomatoes, you'll remove the skins by cutting an "X" into the bottom of the tomato with a knife and boiling for 1 minute.  The skin will then peel off easily) 
  
• Put your fruits or vegetables along with the proper additives into jars.  The additives (lemon juice, vinegar/spices, or sugar syrup) aid in food preservation and allow you to can at lower temperatures.  The proper additive will vary depending on what you are preserving, but will be listed in your recipe.
  
• Wipe of the lip of the jar with a clean paper towel and screw on the top.  (The lids should be sanitized by first boiling them in water)
  
• Place the jars into a pot so that the water which completely covers the tops
• Boil for 10-50 minutes depending on what you are canning and the size of the jar you are using.  You can find processing times listed in the USDA Complete Guide to Home Canning, your pressure caner instruction manual, or at cooking and caning web sites on the internet.
  

Equipment for Hot Water Bath Canning

The only equipment you need to do hot water bath canning is a large stock pot, a pair of canning tongs to remove hot jars from the pot, and special canning jars. 

These canning jars are made of thick glass to withstand the heat of the canning process and a special lid with a rubber gasket seal.  Canning jars are manufactured by two companies (Ball and Kerr) and are widely available at hardware stores, Wal-Mart and other retail locations.

The Bad News about Hot Water Bath Canning

Now here's the rub... The hot water bath process is good for many, but not all, canning applications.  Specifically, it's good for jams and jellies (sugar syrup additive used), canned tomatoes (lemon juice additive used) and pickles (vinegar and pickling spice additive used).  

If you want to preserve green beans, but don't want to add vinegar and pickling spices which will alter their flavor, boiling water alone will not be sufficient to prevent your food from spoiling.  You'll need to heat the food you are preserving to a temperature above that of boiling water and will need a pressure caner to accomplish this.

Pressure Canning

Pressure canning is a process which allows you to heat your canned vegetables and fruits above the temperature of boiling water (212 degrees Fahrenheit or 100 degrees Celsius).  As I mentioned above, by canning using higher temperatures, you're able to preserve a wider range of fruits and veggies and to forgo the use of additives in some cases.

Pressure canning works by using steam to do the preservation.  Under pressure, steam can reach much hotter temperatures than boiling water --generally temperature between 228 to 250 degrees Fahrenheit (107-118 degrees Celsius).  

I should also mention that pressure canning can be used to do all of the same foods that can be done using the hot water bath method, but to complete the canning process faster because you're using a higher temperature.

Pressure Caning Process

• To do pressure canning, you prepare your fruits or vegetables according to the recipe you are following.  This will be very similar to the hot water bath process.
• Fill the pressure caner with water so that the water level is about 1.5 inches above the bottom of the pot. 
  
• Place your jars into the pressure caner.  You will put the jars onto a rack that sits just above the bottom of the pot in your pressure caner that prevents the cans from sitting directly on the hot bottom of the caner.
• Lubricate the metal seal on the cover of the caner with a little Vaseline to prevent sticking and then screw down the lid being careful to gradually and evenly tighten opposite wing nuts.  This ensures that the cover will be properly sealed.
• Bring the the water to a boil.  You'll see steam escaping from a small vent at the top of the pressure caner.
• Place a weight (supplied with your caner) on the vent using a set of kitchen tongs so you don't get burned by escaping steam.  The weight will have settings for 5-15 pounds of pressure.  Use the setting specified in your recipe. (I describe the function of the weight in the last section of this post for those with inquiring minds)
  
• Steam for the time given in the recipe.
  
• When the cooking time has elapsed, turn off the stove. 
  
• Let the temperature/pressure gauge of your caner return to 212 degrees Fahrenheit/0 pounds of pressure.
• Gradually remove the hot weight from the pressure caner using a kitchen tongs so you don't get burned.
• Open the top and remove your preserved cans.  Allow to cool.

Pressure Caners & How They Work

There are two devices on the market - pressure cookers and pressure caners.  If you are canning fruits and vegetables, you want to buy a pressure caner.  Both devices work on the same principle of using steam to do the heating, but caners are larger and designed for caning jars.  Cookers are too small and the USDA warns against using them for canning.

A good brand of pressure caner is All American but there are other good brands on the market.  You can buy a variety of different sized pressure caners, but a  21 quart pressure caner is a good size for home caning applications.

The caner is basically a stock pot with a lid that can be screwed down to hold in pressurized steam. The lid of the caner has a gauge on it that will tell you the pressure in pounds per square inch (PSI) and the temperature within the pot.  There is also a small vent pipe on the top of the pot that allows steam to escape.  You control the pressure withing the pot (and hence the temperature) by regulating the amount of steam that is able to escape through this vent pipe.  You regulate the pressure by placing a small weight (supplied with your pressure caner) on top of the vent.  My weight has three settings on it and allows steam to escape so that the pressure in the pot is 5, 10 or 15 PSI.

If you are an experienced home caner, please feel free to add comments to this post.

      

Comments

[Account Deleted]

My mother-in-law for years canned jars and jars of food when she had a garden. My wife and I tried it too for a while. But it is quite a bit of work, it results in lots of heavy jars that need storage space, and it produces a product that is overcooked and doesn't have the characteristic of the fresh equivalent.

So for all these reasons, we gave it up. It's fun to try, but these days fresh is often available almost year-round, and most people (not us) find frozen a better substitute than canned.

By the way, I'm curious about the high-pressure canner because my wife recalls her mother canning green beans in the old days and she never had one of these contraptions. I suppose salt is the answer?

[H. Mark Delman]

Hi Steve:

When I freeze, I first cut the veggies up and then blanche them in boiling water. I then put them in a vacuum seal bag and uses a counter top sealer to create an air tight seal. I find the work involved in freezing to be about the same as canning.

Like you, I also generally prefer the taste of frozen veggies to canned. For example, canned green beans have a retro flavor that reminds me of what grandma served. That said, I do think canning is better than freezing in a few specific applications -- preserving tomatoes for tomato sauce, pickles, preserving fruit as jams/jellies. As a result, I do both canning and freezing depending on what I want to preserve.