Wednesday, September 8, 2010

Food Preservation part 2 - Freezing

Freezing is exposing food to extreme cold, slowing the rate of decay and growth of organisms. Ideally, to make the most of freezing as a form of preservation, you would need to have a large freezer or “deep freeze” to accommodate your food. Not all foods freeze well, so it is important to do some research before buying a 25-pound box of whatever, making sure it is worth your time and effort.

Freezers come in a variety of styles and sizes, and there are many important factors to consider when buying a freezer. The two biggest considerations are the volume you require for your family (if you plan to store a side of beef, for example, along with your produce, bigger is better), and how energy efficient the freezer is. Chest freezers, while many people find them less convenient, are more energy efficient that upright freezers. When you open the door of an upright freezer, all that cold air just comes out right at you, whereas with a chest, it all stays down at the bottom of the freezer. Check the number of watts or amps the freezer uses. My 20 cubic foot upright freezer is about 10 years old, and was a mid-range model... it uses only 2 amps. My parents just bought a 7 cubic foot chest freezer that uses 5! That is a huge difference in power consumption! In an emergency, we can run our freezer off our solar panels without even taxing the system. Another consideration is whether or not to buy a frost-free freezer. I am a fan of NOT going frost free and here's why. Frost-free freezers tend to be more expensive than conventional freezers and they use more power. Yes, it is inconvenient to have to defrost the freezer, but I only have to do it once a year, sometimes only every other year. Frost-free freezers also tend to dry out your foods. The cycles of frost-free units dehydrate the air, so it makes sense that they would dehydrate your food too, causing freezer burn more quickly.

Here is a photo of Cliff cleaning out our freezer last spring.  It really only took a couple of hours because we put pots of hot water on the shelves, allowing the steam to help the thaw and then picking off some of the ice as it loosened up.  Once the ice was all melted, we hosed it out and wiped it down, inside and out.  It is important not to force it to thaw too quickly or to use a hammer, pick, or other tool to pry off the ice; this could damage the coils in the shelves of your freezer.

There are 2 key factors to keeping food looking its best the longest and saving wear and tear on your freezer, temperature and capacity. Keep your freezer at 0 degrees F. At higher temperatures, food loses quality much faster. A full freezer is more energy efficient because it doesn't have to work as hard to maintain temperature.

Organization of your freezer is key to know what you have and how old your food is. In my upright, I have cheap IKEA bins that I labeled, so I can grab the one for the meat I need and grab the cut I want from it. All vegetables go in the basket in the bottom. Jars of soup and stock are in the door with butter, bread, etc. My next freezer will definitely be a chest. My plan for organization is to take the cheap $1 reusable grocery bags and pick a color for each food type. Vegetables go in a green bag, beef in a red one, etc. This way, I can tell at a glance where you need to look and grab that bag.

Ideal containers for freezing are uniform in size or shape, do not become brittle at low temperatures, and allow for easy sealing and marking. Personally, the only time I use containers for storing frozen foods is for delicate berries, such as raspberries, and for leftovers. I do use some canning jars for storing soups and stocks as they fit well in my freezer door, but I've found that headspace is critical when using jars. I once overfilled a jar of spaghetti sauce and when I pulled it out of the freezer, the jar broke in my hand, leaving me with 3 stitches in my thumb.

I prefer to vacuum seal my meat and produce for freezing. By removing excess oxygen, food lasts longer and is even less prone to freezer burn. According to, food last 5 times longer and you can save up to $600 a year on wasted food. I don't know my results are THIS good, but I do love my FoodSaver. Most meat and vegetables will last a year or more without noticeable (at least to me) decrease in quality if stored properly. General guidelines for expected life of frozen foods can be found here. Vegetables and even some fruits should be blanched before freezing. I will go through this in depth in a later post.

That pretty much sums up the basics of freezing as a method of food preservation. Next up, dehydrating and cellaring. Enjoy!

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