Food preservation has become popular again with the urban gardening movement. There are only so many tomatoes and zucchini you can eat or give away, so why not preserve them and eat them later? Here is a summary of preservation techniques: freezing, fermenting, canning or jam making and dehydration.
I presume everyone reading this has used a freezer before. While raw foods don’t always thaw well, (frozen lettuce? Ewww…) frozen spinach tastes a lot like fresh once it’s cooked. If you are freezing fresh produce, wash and dry fruits and vegetables, remove pits and cores, cut large items into 2” pieces and freeze in zip lock bags. Squeeze the bang gently to remove most of the air before you freeze it to reduce freezer burn and ice crystals. Raw meat, soups and wet cooked foods are also ideal for freezing. Write dates on your frozen foods and eat within 3 months for best results.
Before we had refrigerators and freezers, everybody ate fermented food. Without refrigeration, fermentation is inevitable. While some bacteria will make you sick, many strains are beneficial and can actually preserve your food. For example, if organic raw milk is left out, the good bacteria in the milk will make lactic acid, which dangerous bacteria can’t abide. This fermented milk is known as clabber, and it was more common than fresh milk back in the day.
Many popular foods are fermented. Some examples are sourdough bread, coffee, chocolate, salami, olives, yogurt, cheese, soy sauce, pickles, wine and vinegar. A starter culture of the desired bacteria may be added to the food to ensure it grows, and anti-microbial ingredients such as salt, acid, herbs and spices prevent unwanted strains from taking hold.
While the idea of making fermented food may be scary, it is an easy, delicious and useful way to preserve summer produce from the garden. Good bacteria live on the surface of fruits and vegetables, and the fermentation process encourages the growth of these strains.
I’m currently in love with preserved Meyer lemons. This Moroccan condiment is simply lemons that are cut in quarters and crammed into a jar with plenty of salt and allowed to ferment for a month. The resulting flavor is tart, salty and complex, and I love to rub it in on chicken before roasting it.
Sauerkraut and lacto-fermented pickles follow a similar process, and can include a wide variety of vegetables. Pickles are made from whole or large chunks of vegetables that are allowed to ferment in a salty or vinegar based brine. While most people associate pickles with cucumbers, I prefer firm vegetables such as carrots, radishes and cauliflower.
Sauerkraut making is very similar to pickling. Sauerkraut differs in that the vegetables are chopped finely, and is made exclusively with salt, not vinegar. Salt draws the juice out of the chopped vegetables, providing a wet environment for the good bacteria to grow. The good bacteria in salt pickles and sauerkraut protect the vegetables from pathogenic bacteria by producing lactic acid, much like the clabber I mentioned earlier. This acid lends a sour flavor that is familiar to those who enjoy pickles and sauerkraut. I teach sauerkraut classes every spring and fall at the Albany recreation center, so you can learn for yourself how easy and fun making fermentated vegetables can be. Check my events page for the next available class. If you wish to experiment with a wide range of fermentation techniques, I recommend the book, Wild Fermentation by Sandor Katz.
Canning and Jamming
Fruit preservation is an ancient process that was invented in the Middle East thousands of years ago, but modern canning techniques are only about two hundred years old. In the canning process, foods are initially boiled with acid, salt, or sugar to prevent the growth of dangerous bacteria, particularly clostridium botulinum. The food is then carefully stored in a hermetically sealed, sterile containers. While thousands of people have canned food at home safely, I am not a fan of this process for several reasons.
- Most canned vegetables don’t taste very good.
- It’s very easy and very dangerous to get it wrong. There are a lot of unsafe canning recipes on the internet.
- Botulism is lethally poisonous and canned foods which contain clostridium botulinum don’t smell or taste different from safe food.
- Vitamin C, E and many important B vitamins are destroyed by the long cooking process and extended storage.
Freezing, fermenting and dehydration are easier, safer and more nutritious in my opinion.
That said, people do love jam and canned fruit. And it’s no wonder, since the main preservative in these foods is sugar. If you wish to lesson the amount of sugar in jam, add lemon juice to increase acidity, which kills bacteria. I recommend careful research and reliable recipes if you wish to attempt canning and jam making on your own. Here is a great article by Homegrown.org that offers tips for safe canning.
This preservation technique has been practiced since ancient times in arid climates. Bacteria need water to survive, and dehydration, especially with the addition of salt or sugar, is an easy and safe preservation method. Dried meat and fruit are the most common and traditional dried foods, but kale chips and dehydrated vegetable crackers are new and delicious ways to preserve and enjoy vegetables year round. The ingredients in dehydrated veggie crackers can be varied depending on which crops are in season. This is a boon if your garden is producing more food than you can eat. The most important thing to remember with dehydration is to dry the food a little more than seems necessary. Food that feels dry may still contain traces of moisture, especially if the pieces are soft or flexible. Even the smallest amount of moisture will allow bacteria to grow. The addition of salt, garlic and other anti-microbial herbs like thyme provides flavor and additional protection from bacteria.
It’s fascinating that people have been drying, fermenting food and making jam food centuries before Louis Pasteur, the microbiology pioneer, who began his studies in the mid-1800s. I hope this knowledge will give you courage to try some of these techniques yourself. The processes are simple if you follow the correct procedures. Take a class, read a book, test a recipe at home and the results will delight you.