Hot pack canning involves boiling the food to reduce its size and remove excess air before packing it into heated jars. Cold pack canning on the other hand is placing uncooked food directly into the heated jars. In both methods the jars are preheated and it is necessary to boil any syrups or liquids added to top off the jars.
How Do Hot Pack Canning and Cold Pack Canning Differ?
What is Cold Pack Canning?
Cold pack canning is sometimes called raw packing. It is the process of filling mason jars with raw uncooked foods. Boiled syrup, water or juice can then be added up to the headspace point.
Even though it is called cold pack it is important to start with heated jars. Place your raw food items into the jar remembering to leave sufficient headspace for proper sealing. You can then top the jar off with boiled liquids. Again remember to leave the last inch or so open to allow the necessary headspace.
Cold pack is most often used with pressure canning recipes, though it can be used with some water bath recipes when making pickles and similar high acid content foods. Often cold packing will result in a firmer end product than hot packing.
Keep in mind though that after a few months it is common for the canned foods to change color slightly. Do not be alarmed by this discoloration as it is expected due to the higher air content remaining in the jars.
What is Hot Pack Canning?
Hot pack canning is the process of first boiling or cooking the foods you are going to be canning. These foods are then added to the heated jars. Hot packing is used more frequently with water bath canning although it is sometimes used in conjunction with a pressure canner.
Hot packing helps to remove some of the excess air trapped in the foods you are canning. If analyzed closely raw foods can contain between 10 and 30% more air. When you hot pack this excess air is replaced by liquid and the food tends to shrink.
This results in a more evenly colored product and one that is likely to last a bit longer.
Why Would I Choose Cold Pack over Hot Pack Canning or Vice Versa?
Both hot pack and cold pack canning have their own advantages. As already mentioned hot packing can result in a longer shelf life and less discoloration of the foods.
However, hot packing can lead to somewhat softer foods and this may not be ideal in certain foods. For instance pickles and green beans are much better if they remain crisp through the canning process.
Cold pack canning works best for highly acidic foods such as pickles and tomatoes since they need very little additional processing. It is also used for pressure canning since the longer pressure times ensure that the food will be thoroughly cooked once the process is completed.
When you are going to can meat it is almost always recommended to use the hot packing method. When doing so remember to boil the added juices needed to bring the liquid up to the headspace as well.
How Do I Know If I Should Hot Pack or Cold Pack When Canning?
It is recommended that you follow a known and tested recipe when canning. These recipes will normally make it clear if you should be hot packing or cold packing. We have several easy recipes in our recipes section. Additionally, you can check out our list of the best canning books to find some cookbooks with hundreds of tasty canning recipes.
While there is never a time when you must hot pack it is often the preferred manner for various reasons. Just remember to use a tested recipe and don’t over think the process. Make sure to check out our list of the equipment you need to get started canning.