Let’s take a moment to explore the difference between two kinds of preserving: water bath canning, and fermentation. There won’t be too much of a discussion about processing times or anything too technical for water bath canning, mostly just a general overview of what it is so we can clearly see the difference.
Water bath canning
Water bath canning is an excellent way to preserve the textures and flavors of fresh fruits and vegetables. Jars are filled with the desires food and usually some kind of brine or sauce, a new lid is placed on it, and it is boiled for a determined amount of time sealing the jar. A sealed jar exists in a kind of stasis, having an internal environment sealed off from oxygen. Oxygen availability is the main cause of food spoilage. Most microbes, molds, yeasts and bacteria, that consume food and cause spoilage require oxygen to grow. Food that has been properly water bath canned can sit at room temperature and remain shelf stable for a number of years.
Water bath canning is a fairly safe procedure if proper canning protocols are followed. The things that need to be considered are sterilization and acidity, as well as ensuring the seal is new and seals properly. Jars used for canning need to be sterilized, either in a dish washer, by boiling the jars for a set amount of time (about 10 minutes) or baking them in an oven (220f for at least an hour). That’s because bacteria are on everything. The food that is canned also needs to be brought to a boiling temperature either in the can or immediately before being put inside it to destroy any bacteria present on or in it.
“The botch, bud.”
Having the right amount of sugar or acid present is a big one though. Both act as a preservative: many things such as fruit are sufficiently acidic already, so they are mixed with sugar to be their primary preservative in the form of jams, etc. Vegetables tend to be substantially lower acid which requires the addition of acid, usually in the form of lemon juice or vinegar to lower their pH. Acid environments are much harder for bacteria to grow in than a more neutral environment. Although there is one particular bacteria that causes worry with a water bath canned product: Clostridium botulinum, or more commonly known as botulism.
Clostridium is mostly benign, and lives on pretty much everything. It’s in your hair, probably in your nose or on your lips, on the table, the curtains, dirt – whatever, shit’s everywhere. The bacteria itself is non-harmful, and for good measure it gets killed by a good bleaching or being brought up to a boiling temperature. It however has a very special property that only gets activated when conditions are right. When Clostridium is in a low-acid, ambient temperature, anaerobic environment it releases what are called botulism spores, that secrete a very deadly poison called botulinium. Botulinium is one of the most deadly poisons to human beings, basically causing a nervous collapse. It’s worth noting that food born botulism poisoning is incredibly rare, affecting only 39 people in the United States in 2015. A low acid environment is considered one higher than 4.6 pH, ambient temperatures are between 4C and 60C, and anaerobic means no oxygen, like in canned food for instance. Therefore, low acid foods anaerobic foods, like garlic in oil, can be stored in the fridge without much botulism poisoning risk.
There are ways to can low-acid foods, like meat, using a pressure canner, but we won’t get too much into that.
Acid rap and basic bitches: the pH scale for highschool drop-outs.
The pH scale is a chemistry thing used to discuss the acidity or basicity of a solution. The scale uses the numbers from 0 to 14. The number 7 is considered neutral – so not acidic or alkaline – whereas anything lower than 7 is considered acidic and anything over 7 is considered basic or alkaline. In terms of flavor, acids are sour – lemon juice having an acidity of about 2.2 – and basics are bitter, beef bile having a pH of about 8. Drinking water is usually around neutral (7).