Safe, modern canning techniques

In my opinion, canning is a must if you are serious about growing your own food. Canning is a bit of science, and it's important to understand safe canning techniques. Many of the techniques that our ancestors used are now understood to have limitations that often lead to spoiled food and occasionally to health risks. I remember my grandmother's canned strawberries and they are a part of why I can now - but I don't follow her techniques now that we have access to more foolproof, safety tested approaches.

There are three safe canning approaches - water bath canning, steam canning and pressure canning. This blog post will give an overview of each approach and will also enumerate a few techniques that aren't considered safe or foolproof anymore.  Finally I'll give a few of my favorite resources for recipes.

Water bath canning

Water bath canning is the most traditional canning technique. It is a good one to start with because you probably already have everything needed. Water bath canning consists in bringing a very large pot of water to boil, then completely submerging the mason jars in this water for a prescribed amount of time. It is safe and effective for foods that have a high acidity (for example pickles, tomato based products with a bit of lemon juice added, jellies and jams, condiments, sweets). 

Pros: 

1. No specialized equipment available
2. Simple to learn
3. Many safety-tested recipes available

Cons:

1. Takes a long time to get this much water to boil
2. Wastes water and electricity
3. Can produce a lot of steam (humidity in the house)
4. Pot is very heavy - could be hard to manipulate for some people, and risk of dropping a large amount of hot water
5. Only effective for acid food

My water bath canner (on the left on the stove), the classic, inexpensive one you can get at big box stores. Any big pot will do.

Steam canning

Steam canning is a more recently studied type of canning. You need a special steam canner, which sometimes has a built in gauge. The canner isn't air tight. You put a small amount of water at the bottom. The jars are placed on a rack above the water. Once the pot is full of steam (and the gauge is in the proper zone), you start a timer and keep the jars in this steamy environment for the prescribed amount of time. Most water bath canning recipes can be accomplished using steam canning - the only exception is recipes with a very long sterilization time (generally quotes as more than 45 minutes), because your canner may run out of water as the steam escapes. Steam canning is an old technique but it was only recently studied scientifically and proven to be safe.


Pros:

1. Faster than water bath canning due (less water to heat)'
2. Easier to handle and less water wastage
3. Lots of recipes available since all water bath recipes can be used for steam canning (except those longer than 45 minutes)

Cons:

1. Need a Steam canner (but the steam canner can also be used as a big stockpot and as a water bath canner if needed so it's quite handy).
2. Only effective for acid food

My steam canner. It's a Harvest Guard with a gauge. I appreciate having the gauge and clear lid.

Pressure canning

Pressure canning is the only proven safe canning method for low acid foods including things like non-pickled vegetables, soups, meat, fish, broth, etc. It requires a special pressure canner. In Canada, the most readily available is the 23 quart Presto brand pressure canner. If you eat meat, it's a must - as a vegetarian, I find it very handy too. Pressure canning can be a bit intimidating for some, but, the manual is very clear so there is no reason to be intimidated. If you live in Canada, it will be hard to find a place to calibrate your pressure gauge, but you can write to Presto and they will send you a 3-piece weighted gauge that does not require calibration.

Pros:

1. Only proven safe method for low acid food

Cons:

1. Requires a somewhat expensive Pressure canner
2. A bit more technical to understand.

My presto 23 quart pressure canner with a weighted gauge, the best option in Canada. In the picture, the weight hasn't been put on yet (it's in the venting stage)

Canning methods that haven't been proven safe

Many canning methods used traditionally, internationally, or otherwise, have not been studied scientifically. Personally, I choose not to use these methods. There is a risk of adverse health effect (or even death) with all of them. Furthermore, even if you don't get sick or die, you risk your food spoiling and growing and canning food is too much work to take a chance, in my opinion. Some of the methods that you may encounter that haven't been proven safe include:

• Open kettle canning - Pouring hot food into jars and closing them. 
  
• Oven canning - Heating full jars in the oven
  
• Dry canning - Putting ingredients in the jars without liquid covering them and then processing them using any method (including oven canning and water bath canning)
  
• Sealing jars with wax
  
• Turning jars upside down to help them seal or to "sterilize" the lid (often in combination with open kettle canning)
• Water bathing low acid foods (including meat) using very long processing times

Most people's arguments for using these techniques is that they know someone who uses them and nothing bad has ever happened. That may be true, but it doens't mean nothing bad ever will happen. Or, more likely, they may not have heard about the times things didn't work out (my grandma definitely threw out moldy wax covered strawberry jam more than once). It is also possible that some of these techniques will one day be proven safe but until then, I stay away from them for the aforementioned reasons. 

My favorite resources for safe canning

I learned to can using the pick your own website. It is full of easy to follow recipes and the recipes follow safe practices. 

The National Center for Home Food Preservation (US based) has very detailed and extensive recipes. Most are pretty basic and unimaginative but they cover a lot of staples. 

Recent canning books by Ball or Bernardin (the Canadian brand of Ball) generally adhere to safe canning practices.

The Facebook group "Canning and preserving with love" has many knowledgeable admins and a considerable repertoire or safe canning recipes

The website created by Vincent le canneux, in French, has safe recipes. Vincent used scientific protocols to test his recipes. 

The Facebook group "Conserves Maison, Cannage, hommage à Vincent le canneux", in French, has many knowledgeable admins.

Tentatively I would say that Ricardo's recipes generally appear safe.

Some books and resources to steer clear of include books by The Canning Diva, Miss Conserves (French), and Canning Rebels Facebook groups. These all encourage techniques that aren't proven safe.