Looking through the food preservation sections of old cookbooks, I love the recipe names that are associated with a particular cook: Aunt Ellie's Spiced Cherries, Lulu's Bread 'n' Butter Pickles, etc. Coming up with your own signature recipes is one of the joys of food preservation. But before you can start playing around with making a recipe your own you need to be 100% certain it will safely preserve the food.
Once you understand what makes a particular food preservation method work--how and why it safely preserves the food--then you will know when you can improvise vs. when you need to stick to a recipe's ingredients and instructions exactly. The information below will help you develop your own unique recipes while honoring the preservation processes that make the food safe.
"Canning" can be a confusing term. For one thing, most of us aren't actually doing anything with metal cans. Instead, we're putting up food in glass jars. But "jarring" has the negative connotation of a rough jolt. So we say "canning." when we are talking about creating a vacuum seal on jars of food.
How do you know which method is safe to use?
It depends on whether the food is acidic or alkaline. Non-pickled, low acid vegetables and animal products must be canned in a pressure canner. Fruits, sweet preserves , and vinegar pickles may be safely canned in a boiling water bath.
Pickling is another double-meaning food preservation term.
There are pickles made by adding vinegar for acidity, such as these tasty Mediterranean-style green beans.
f you're fermenting, remember that lacto-fermented pickles do not need to be canned. In fact, they're better if they're not. The heat of the canning process destroys the healthy, probiotic bacteria in lacto-fermented foods. These probiotics are super good for you, so skip the canning with ferments.
When improvising on a non-fermented, vinegar-based pickle recipe, keep in mind that it is the acidity of the vinegar that is safely preserving the food. Tinker with the herbs and spices and which vegetables you use, but do not dilute the vinegar any more than the recipe specifies. If the pickle is too vinegar-y for your taste, add a little sugar or honey to soften the flavor but keep the vinegar strength unchanged.
If you're not riffing on a recipe but inventing one from scratch, be sure you are using vinegar that is 4.5% acetic acid or higher, and that you do not dilute with more than an equal amount of water (a 50/50 vinegar - water ratio).
Botanically speaking, tomatoes are a fruit. It used to be that you could safely can tomatoes in a boiling water bath. That was because old-fashioned varieties of tomatoes were acidic. However, in recent decades tomato varieties have been bred for low acidity. It is still possible to process tomatoes in a boiling water bath, but you need to add lemon juice or vinegar (1 tablespoon per pint) to raise the acidity of the tomatoes.
Fruits and Sweet Preserves
Cooks tend to think of "acidic" as meaning sour, but in scientific terms sugars count as acidic on the pH scale. All sweet fruits can be processed in a boiling water bath, no special equipment necessary.
Likewise, all sugar or honey jams, jellies, and preserves can be safely processed in a boiling water bath.
When altering a sweet preserve recipe such as a jelly, keep in mind that jellies depend on pectin in order to gel. If the original recipe called for a high pectin fruit such as apple and you swap in a low pectin fruit such as peach, you will not get a good gel unless you add commercial or homemade pectin.
Chutneys, Relishes, and Ketchups
Chutneys, relishes, and ketchups are sweet and sour preserves that can be safely processed in a boiling water bath. Experiment with the seasonings, fruits, and vegetables you use, but do not dilute the vinegar. It is also possible to make vinegar-free lacto-fermented chutney.
So long as you keep in mind which part of a food preservation recipe is responsible for safely preserving the food, you can improvise freely with the ingredients that are only about flavor, not safety. Soon you'll be inventing your own signature recipes to share with family and friends.