Too many carrots? Preserve them with low acid food preserving technology.

Author: Valerie Pearson  |  Date Posted: 23 November 2010

I am still harvesting carrots out of my garden, have filled up a draw in my freezer and now I have moved onto bottling and filling up the pantry. Here's how.Low Acid Food Preserving:Many people have been making home preserves such as jams, jellies and pic

I am still harvesting carrots out of my garden, have filled up a draw in my freezer and now I have moved onto bottling and filling up the pantry. Here's how. Low Acid Food Preserving: Many people have been making home preserves such as jams, jellies and pickles; and some of us have been preserving fruits and tomatoes in our kitchens on a regular basis for years. All of these foods have one thing in common; they are high acid foods. By high acid, I mean that that have a pH level above 4.6 on the pH scale. Our foods have a pH level, which is the measure of how acid or alkaline that food is. The pH level scale runs from 1 to 14 with 1 serving as “very acidic”, 7 being “neutral” and 14 being “very alkaline”. For example, most fruits are considered high acid foods; which means that they have a pH level of over 4.6.on the scale, covering from 4.6 to 1 on the pH scale with 1 being the highest. Tomatoes also fall into this group, but there are now such a variety of tomatoes on the market, including tomatoes especially grown to be low acid, that extra care must be taken to ensure that the tomatoes used are not too low acid. Most vegetables are low acid foods; which means that they fall below 4.6 on the pH scale, covering the range from 4.6 through to 14 on that scale with 14 being the lowest. This covers such foods as green beans, corn, peas, beets, carrots and many more. This would also include meats, poultry and seafood, which can be preserved using methods especially designed for low acid foods. Low acid foods cannot be preserved with the boiling water bath method, designed for high acid foods, as this method will not kill the bacteria that can survive in low acid environments; the same bacteria that is not a problem in high acid environments. Low acid foods require processing at a temperature of 116 degrees centigrade for safe preserving to avoid the potentially fatal poisoning by botulism. Botulism is a poison produced by "Clostridium botulinum", a bacterium that is found everywhere; in soil, on raw fruits and vegetables and on meat and fish. Botulism spores are resistant to heat, even from boiling water, and thrive in a moist, oxygen-free environment, such as a jar of food. While "Clostridium botulinum", will not harm you in the form it is found in on fresh foods, when fresh food is preserved in a jar, the right conditions are created for the bacteria to create the poisons toxins, if not processed correctly. The problem then becomes how to preserve these low acid foods? The solution is simple. Low acid foods can be processed at a high enough temperate (116 degrees centigrade) to kill "Clostridium botulinum” with a pressure canner and this makes this form of preserving low acid foods a safe alternative to drying and freezing. A pressure canner is a large, cast-aluminium pot with a locking lid and a pressure gauge. By cooking under pressure, you can bring the temperature of boiling water up to 116ºC (240ºF). This is the minimum temperature required to destroy botulism spores, and the only way to guarantee safe preserving for food items such as vegetables, meats and seafood. Your pressure canner will come complete with instructions so be sure to always follow them carefully.
It is important to keep the pressure above 10 pounds, so I always use 11 pounds, just to be on the safe side. The time for processing your jars will be determined by the contents of the jar and by the size of the jar; the larger the jar, the longer the processing time. Be sure to never cut short the processing times that are recommended in the publications that come with the canner and that are available in many books on preserving. These times have all been proven and tested by various health departments around the world and can be relied upon for their accuracy and safety. If you live more than 1,000 feet above sea level, then both the pressure and cooking times will have to be adjusted. There are charts available to assist you with this in the same publication as the standard times and pressures are located. Once the right pressure is reached during cooking, it must be kept constant throughout the cooking step. Do this by adjusting the temperature setting on your stove top and watching the gauge to ensure that it never goes below 11 pounds and, equally important, that it stays not too far above that pressure. This is easier than it sounds, as once the pressure is reached; you just lower the cooking temperature to a level where it just maintains the pressure. On my stove, which is electric, I just turn it to low once my desired pressure setting has been reached and it keeps the pressure between 11 and 15 pounds with little fluctuation. I do stay in the kitchen the whole time that it is processing, but continue on with my other cooking, bread making or cheese making and only glance at the gauge form time to time. I have been using used jars form the grocery store for all my preserving for over 20 years. I collect them form neighbours and work mates and have an endless supply, especially if I in return give them a jar or two of my creations from time to time. It is important however to always use new lids when preserving low acid foods. The seal in the jar, which can be seen on the inside of twist top lids, deteriorates with time and use, so only new lids can be guaranteed to give you the perfect seal you will need. This year I have a glut of carrots and preserved some in jars. Method: Prepare your jars. Wash the jars you are going to use in hot, soapy water and then rinse well. Check them carefully for any damage, such as a chipped rim, and discard any damaged jars. Leave them in a sink of hot water waiting to be filled with you hot green beans. Do the same to the lids and leave them in a sink of hot water waiting to be placed on the jars once full. Remember, I use recycled jars from food purchased at the grocery store, but I always use new lids to ensure I get a good seal. Hot Pack Method: Preparing your Carrots. Wash, peal and chop your carrots to the desired size. Cover the carrots with hot water and quickly bring them to the boil, boiling for 5 minutes. Packing the jars: Remove the jars from the hot water and pack the hot carrots into the jars you have pre-heated, leaving 25mm headspace. Top off the jars with the cooking water to cover the carrots, being sure to still retain the 25mm headspace. With a spatular or butter knife remove any air bubbles in the jar, wipe of the jar rims clear and put the lids on securely.
Processing the jars: Place the jars in your pressure canner, on top of the removable bottom rack, ensuring that they are not touching each other. Add the water, as directed and secure the lid. I use about 3 litres of water in my 21.8 litre canner.   The water does not need to cover the jars, as it is the pressure created within the canner that will enable the food in the jars to reach the required temperature.
Following the directions of your canner manual, heat the canner and contents on your stove top, and allow the excess steam to vent for 10 minutes from the vent pipe. Then place the pressure regulator on the vent pipe, which prevents further venting and starts the pressure building. Monitor the pressure gauge as it increases. Once it has reached the desired pressure reduce the heat to maintain that pressure, making any minor adjustments over the preserving time, as necessary. For 500ml jars process at 11 pounds pressure for 25 minutes and for 1000ml jars process for 30 minutes.
This method works with all your low acid food, with variations on the processing times depending on the food processed and the jar sizes used. All the information you need comes with your canner, including instructions for preserving an extensive list of vegetables, meat, poultry, fish and other seafood. Having preserved this way for over 20 years, I can honestly say I would not know what to do with out my pressure canner. It has become an invaluable tool in my kitchen that has helped me stock my party with all manner of food. You can do this with beans, beets corn, soups, stews and much more. All my food is now preservative and chemical free, as the ingredients are under my control. The cost savings are tremendous, especially if you are preserving your own harvest. Even if you do not have a large veggie patch, there are certain times of the year that all foods are at their best and most plentiful. This is the time to buy and preserve them for latter use. So if you have been preserving fruits, or making pickles and other high acid preserves, this is a way you can now preserve low acid foods without drying or freezing them. While I still do a bit of drying of some foods, I no longer use a freezer at all due to their high consumption of energy and the associated cost to both myself and the environment. Pressure canning uses some initial energy, but the foods can then be stored in the pantry until used with no further cost. Now it's your go!