A few interesting questions about canning

I have been doing some canning lately. So, I wanted to share some interesting questions (and answers) you can encounter when canning.

How safe is it to eat canned food that was frozen and then thawed?
Freezing should not harm the canned food. But before consuming the thawed canned food check it thoroughly. But, if you notice any damages on the food or there is no vacuum upon opening the can, throw it away.

Should I use table salt for canning and pickling?
The answer is no! The reason for that lies in the fact that the table salt you can get at your grocery store is usually not pure sodium chloride. Instead it is a mixture of sodium chloride, dextrose, potassium iodide and calcium silicate. Calcium silicate is an odorless and tasteless anti-caking compound agent that is added to absorb moisture inside the package. Table salt is not recommended for canning recipes because the calcium silicate can discolor some foods and it can cause a clouding effect or settle to the bottom of jar. All these effects don’t make the food harmful but just unappealing.
Use canning and pickling salts, that can be also used for cooking and baking as well as for the table. Kosher salt can be used for canning and pickling as well because is usually pure salt without additives.

Can I use artificial sweeteners when canning fruits?
Better not.  Artificial sweeteners are usually not recommended for canning. For example.   sweeteners that contain aspartame (Equal or NutraSweet) lose their sweetening effect with heat. Sweeteners based on saccharine like Sweet’N Low and  Sugar Twin become bitter when exposed to canning temperatures. So it’s better to add them after you open the canned fruit.
On the other hand, Splenda and Sucralose won’t produce an aftertaste when heated.

Can I use a microwave pressure cooker for canning foods?
This is not recommended. The pressure cookers that are designed for use in the microwave are safe to use for simple cooking of foods. However, you should absolutely avoid them for canning low acid foods because you cannot monitor the actual pressure inside the cooker, and therefore there is a danger of underprocessing the food.

Read here a first hand review for the All American pressure canner.

Is there any difference in canning yellow, orange and red tomatoes?
No. All tomatoes are canned in the same way,  no matter what the color. So, use the standard recipes for red tomatoes. Just make sure to add the correct amount of lemon juice or citric acid.

Is it safe to use homemade vinegar as an ingredient in home canning recipes?
It’s safer to avoid homemade vinegar in canning recipes. To stay on the safe side, it’s recommended to use vinegar of at least 5% acidity when pickling or canning. The vinegar that you can get at  the store is standardized to at least 5% acetic acid. On the other hand, the acidity of homemade vinegar is variable and it could contain more or less acid.

Do I need to add lemon juice or citric acid when canning tomatoes?
Tomatoes are an acidic food and it was once considered that you could safely canned them in a boiling-water canner. However, with some newer and less acidic tomatoes varieties it’s recommended that lemon juice or citric acid should be added, in order to avoid any potential for botulism.
You can add 1 tablespoon of bottled lemon juice to pints and 2 tablespoons lemon juice to quarts of tomatoes. Don’t use fresh lemon juice because its acidity varies. If you use crystalline citric acid, add one-fourth teaspoon to pints and one-half to quarts of tomatoes. You can add the acid directly to the jars before filling.

The tomatoes seeds have turned black in the jars! Is it still safe to eat the tomatoes?
If the tomatoes were processed correctly and the seal of the jar was maintained (the jar was sealed in a vacuum) the discoloration of the seeds is probably not a sign of spoilage. The discoloration is probably a reaction of harmless polyphenol compounds in the seeds with the iron and other minerals that are present in the water.

I noticed a white substance surrounding pieces of the canned vegetables. Is it still safe to eat them?
The cause of that can be the excess starch from over-mature vegetables or precipitated calcium salts from excessively hard water. The use of table salt can cause this effect as well. These situations should not be harmful and the vegetables should be safe to consume, of course, if the food was properly processed in the first place.

Adding grape leaves to pickles? Yes or no?
Grape leaves are added because they prevent the softening of pickles. Grape leaves contain tannins that apparently inhibit the enzymes that cause the pickles going soft. But, if you remove the blossom ends of the cucumbers, that are the source of enzymes, the grave leaves will become unnecessary.


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