How to Home Can: Raw-Packing vs. Hot-Packing

Not all food packing methods are created equal. The USDA explains why when it comes to canning, most foods like it hot.

| July 12, 2011

So you have your food, your jars and you’re ready to can. But wait: There are two different canning methods — raw-packing and hot-packing. What are the differences between the two? And how do you know which method is right for you, and, more importantly, your food? The United States Department of Agriculture's Complete Guide to Home Canning, will show you the hot and raw pack process for almost everything in your garden. Use this and our other canning resources to stock up after your harvest.

Raw-packing is the practice of filling jars tightly with freshly prepared, but unheated food. Such foods, especially fruit, will float in the jars. The entrapped air in and around the food may cause discoloration within 2 to 3 months of storage. Raw-packing is more suitable for vegetables processed in a pressure canner.

Hot-packing is the practice of heating freshly prepared food to boiling, simmering it 2 to 5 minutes, and promptly filling jars loosely with the boiled food. Whether food has been hot-packed or raw-packed, the juice, syrup, or water to be added to the foods should also be heated to boiling before adding it to the jars. This practice helps to remove air from food tissues, shrinks food, helps keep the food from floating in the jars, increases vacuum in sealed jars, and improves shelf life. Preshrinking food permits filling more food into each jar.

Click on the Image Gallery for how-to illustrations of both raw-packing and hot-packing.

Advantages of Hot-Packing     

Hot-packing is the best way to remove air and is the preferred pack style for foods processed in a boiling-water canner. At first, the color of hot-packed foods may appear no better than that of raw-packed foods, but within a short storage period, both color and flavor of hot-packed foods will be superior.

Many fresh foods contain from 10 percent to more than 30 percent air. How long canned food retains high quality depends on how much air is removed from food before jars are sealed.

8/12/2014 4:51:28 AM

How do I buy large quanity of canned food and place in small jars?

9/19/2013 7:04:15 PM

Question: I canned 15 quarts of apples using the hot-pack method. The recipe called for boiling in the water canner for 20 minutes. Through a timing mix-up, they were only boiled for 10 minutes. Everything else was done correctly and meticulously. Do I have to throw out all those apples?

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