Canning Essentials. Jackie Callahan Parente

This is the ideal temperature for flash-freezing foods.

       HOW ACID FITS IN

      The next component in canning is the acid level, or pH. Foods that are high in acid (acidic) call for different (some might say easier) means of preservation than foods that are low in acid (alkaline). See the table “Acidity and Safe Food Preservation” for some specific fruits and vegetables, but as a rule of thumb, fruits (including tomatoes) are high in acid while vegetables and meats are low in acid. Acidity is measured on a scale of pH values from 1 to 14, with 1 being the most acidic and 14 being the most alkaline. The midpoint on that scale (7) is neutral, but for our purposes, the tipping point is a pH level of 4.6. Thus, if a food has a pH value of 4.7 or higher, it will require different processing than foods that are 4.6 or lower. Note: Foods with a pH value of 4.7 or higher cannot be safely processed in a water-bath canner.

      ACIDITY AND SAFE FOOD PRESERVATION

TYPE OF SPOILAGE AGENT	MAXIMUM PH LEVEL THAT AN ORGANISM WILL SUSTAIN	TYPE OF FOOD	METHOD OF CANNING
	1 (Strongly Acidic)
Molds	2
Yeasts	3	LemonsPicklesApricotsPlumsApplesPeachesSauerkrautPears	High-Acid Foods:safe to processat 212°F in awater-bath canner
	4	Tomatoes
Bacteria	4.6		Highest pH level that is safe to water-bath
	5	FigsOkraCarrotsBeetsGreen BeansSpinach	Low-Acid Foods:safe to processat 240°F in apressure canner
	6
	7	Corn
		Peas
	14 (Strongly Alkaline)

      TAKE BABY STEPS

      When you try a new recipe, start small. Even recipes from reliable sources may not work out as well as you’d hoped. Just as you’ve tried recipes from great cookbooks and find that you simply don’t like the way a recipe tastes, or that it doesn’t look like the picture, the same can be true for any of the recipes involving food preservation. First time around, make just one batch. You’ve heard this before, but it’s worth repeating: if you are a novice, start simply. Try water-bath canning or freezing. Freezing green beans is a snap (pun intended) and the results are great! Canning tomatoes or peaches is easy. Making strawberry freezer jam is even easier, but cooked jam is a breeze, too. You’ll find recipes for these in the following chapters. Yes, it’s tempting to want to triple the recipe or try something exotic. But starting small and simple helps you to quickly find what works best for you, and then grow your new skills with confidence.

       PUTTING THEM TOGETHER

      Now let’s bring together the two key factors of acidity and heat. Remember, the high versus low acid determination only impacts food preserved by canning. If you are freezing food, acidity is irrelevant.

       Foods that are high in acid (generally fruits—including tomatoes—and pickled stuff that has a large amount of vinegar or lemon juice) can be successfully and safely preserved when you use a process that heats the food to a level that will kill the yeasts or mold (for example, water-bath canning at 212 degrees Fahrenheit) or reduce the temperature to a level that inhibits the growth (as with cold storage). Bacteria won’t survive in the acid environment.

       Foods that are low in acid (generally vegetables and meats) can be successfully and safely preserved only when you use a process that heats the food to a level (240 to 250 degrees Fahrenheit with a pressure canner) that kills yeasts, molds, bacteria, and bacterial spores or that reduces the temperature to a level that inhibits their growth (as with cold storage).

       A FINAL NOTE ON FOOD SAFETY

      If this is beginning to sound complicated, remember one fundamental truth: if you follow accepted, tested methods and recipes, all of the types of food preservation discussed in this book are safe and will provide you and your family with convenient and nutritious food. There is no reason to fear that your food will spoil or will contain harmful contaminants. You know where your food comes from and you know the care that has gone into its preservation. And I’m going to say it again: there is no one more vested in the safety of your food than you! Not the commercial farms, not the jam-manufacturing plants, not your local grocery store.

       PLANNING: YOUR KEY TO SUCCESS

      With the basics under your belt, you’re ready to begin. While it’s possible, sometimes even necessary, to work on the spur of the moment on a food-preservation project, you’ll find greater success and less stress if you plan ahead. Depending upon what you are doing, this can involve a small or large amount of investment of both time and materials.

      STEP 1: WHAT AND HOW MUCH?

      Decide what you want to preserve and how much you want to end up with. If you don’t have enough of what you want on hand, supplement your stock (see step 2). Check out the “Fruit Yields (Canning and Freezing)” chart in the appendix for approximate yields from a specific quantity of produce to help you answer some of these “how much” questions.

      Don’t forget to check the recommended storage time for the product that you are storing. For example, current guidelines recommend storing canned and most frozen food for no longer than one year. This will help you decide how much to put up so that you don’t run the risk of having to throw it away.

       You’ll find greater success and less stress if you plan ahead.

      Picking your own produce at local farms and orchards can be a fun and easy way to gather the