As you begin to harvest this year’s garden, you may wonder what to do with your bounty of fruits and vegetables. For many, canning is a great way to preserve fresh fruits and vegetables to enjoy them year-round.
If you have never canned before, choosing the right jars for canning can be a daunting process. The wrong canning jar can not only ruin the food you are trying to preserve but could also be dangerous if it cracks or breaks during the process.
There’s no need to worry! Our guide to jar sizes for canning will walk you through everything you need to know about choosing the perfect jars to preserve your harvest.
Jars designed for canning should be made of tempered glass. The tempering process used to create the glass jar helps to prevent breakage under the heat or pressure of the canning process. In addition, the glass should be slightly thicker than typical jars, to ensure that is strong enough to withstand the processing.
Canning jar lids are designed to create a vacuum tight seal that prevents food spoilage. Depending on your method of canning, you may need to purchase a specific lid that is meant to create this seal under these conditions. For example, if using heat through a water bath to preserve your harvest, a lid created to seal at high temperatures may be needed.
When examining your canning jar, ensure that there are no cracks or imperfections in the glass. Even a small crack or insignificant-looking scratch could cause the jar to break under the high pressures needed for canning.
There are two commonly used types of canning jars: regular-mouth jars, and wide-mouth jars. Each jar is best used for certain canning methods and foods.
Regular-mouth canning jars are tapered at the top of the jar, near the lid. You can tell if a jar has a regular mouth if the area directly below the lid is slightly smaller than the rest of the jar, creating a small neck that the lid sits on.
The tapered neck of the jar helps keep certain foods below the liquid level, ensuring that they stay within the pickling liquid. However, the smaller mouth may make it difficult to fit certain vegetables or fruits into the jar.
Regular-mouth canning jars work well for pourable foods, such as:
The tapered neck allows for these foods to be poured more easily from the jar.
They can be a good choice for pickling smaller vegetables that are able to fit through the opening. Regular-mouth jars cannot be used for freezing, as the tapered neck does not allow enough extra space for the liquid to expand as it freezes.
Wide-mouth canning jars are the same width from the bottom of the jar to the lid. When looking at a wide-mouth canning jar, the sides of the jar should be straight, with no taper near the opening.
The wider jar opening makes it easier for larger fruits and vegetables to fit in the jar. Vegetables that are too large to easily fit into a regular-mouth canning jar should comfortably fit in a wide-mouth jar. The wide mouth also makes it easier to remove vegetables once they have finished pickling.
Wide-mouth canning jars should be used if the canned food will be frozen in the future, as the wide mouth allows for enough space for liquid to expand as it freezes.
Canning jars come in a variety of sizes that may be ideal in different applications. Always consult with your recipe and cooking duration when choosing a jar size, as the size of the jar can impact how long the item needs to be processed while canning.
Quart size canning jars are one of the most common sizes used in canning recipes. Their versatility and larger size make them a great choice for canning almost any fruit or vegetable. Keep in mind the mouth size when choosing your canning jar.
Regular-mouth 32 ounce jars can be used in canning most fruits and vegetables as long as they fit through the smaller mouth opening. It is a great choice for larger batches of salsa or smaller vegetables such as asparagus or carrots.
The wide-mouth quart size canning jar is more versatile than the regular-mouth style as it can fit larger fruits and vegetables. It is a great option when canning larger pickles or chunks of fruit.
The pint-sized canning jars are great for smaller batches or testing new recipes. These jars are often used for preserves or smaller pickles. Keep in mind that some larger vegetables may not fit through the opening of a pint size jar, especially when using regular-mouth canning jars.
This small size is great for creating gifts or small batches of jams, jellies and preserves. Some smaller or cut vegetables may fit in these jars if using a wide-mouth canning jar.
You’re almost ready to start canning! Once you’ve decided on a size and shape for your canning jar, don’t make one of these common mistakes.
It may be tempting to re-use jars that you had purchased full of pasta sauce or pickles from a grocery store. However, these commercial jars are not suitable for home canning.
Jars that aren’t made for specifically for home canning are often weaker and less tempered than those designed for this purpose. This makes them more susceptible to breakage when put under heat or pressure during the home canning process. The shipping process and general handling of commercial jars can weaken the glass even further.
In addition, even when using a new lid, a commercial jar will never form as strong of a seal compared to a jar designed for home canning. This could lead to food spoilage down the line.
While it may be tempting to save a little money, the breakage risk and potential food loss isn’t worth the dollars saved.
Canning is more scientific than standard recipes. The jar size is always factored in to the recommended processing time needed to ensure that the food is safe from spoilage.
If you use a larger jar than the recommendation, it will require a longer time to process when canning. Not allowing for a longer time could prevent the food at the center of the jar from heating fully, leaving it susceptible to spoilage. It may also prevent the lid from sealing completely.
Some large jars are not safe for most canning due to their size. Half-gallon jars are only safe when canning juice, nothing else. Their size makes it impossible to heat solid items in the center of the jar. Jars larger than a half-gallon in size are too large for canning.
It is safe to use a jar in a smaller size than listed in the recipe. Process the jar for the same length of time recommended in the recipe, even if using a smaller jar. If making a large batch, use multiple small jars rather than one large one.
Wide-mouth canning jars are the only jar style that is appropriate to freeze canned foods. The wide shape of the mouth will allow the liquid in the jar to expand without putting extra pressure on the glass of the jar. However, you must also leave space at the top of the jar to allow room for this expansion.
When freezing, always leave space one to two inches of empty space at the top of the jar. Some jars will even have a line on them that is meant to be the highest point the jar should be filled when freezing.
Keep in mind your future plans when choosing your jar. If you plan on freezing your canned goods in the future, choose a jar large enough to allow you to have extra space when finished.
It’s time to start canning! Want more tips on how to can your fruit and vegetable harvest safely? Check out our list of canning tips before you get started.