Fermentation is a process near and dear to my heart. I love fermentation. Fermentation, under clean, controlled circumstances, is good for you. The process grows lacto-bacillius, an important pro biotic and vitally necessary for anybody trying to heal their intestines. Research suggests that the process also creates concentrated B-complex vitamins, although not B-12 as was thought at one time. Fermentation keeps food fresh, crisp, and good to eat for months or years and it is much, much easier to prepare food for fermentation than you might expect. I'm not going to discuss the hard science behind fermentation because, well, I just don't know it as well as some other people. For further information, read Wild Fermentation. Fabulous, wonderful book; I cannot recommend it highly enough.
I live just above 6,000 feet of altitude. I consider the FDA/USDA recommended methods of food storage - preserving by heat and/or pressure - to be grossly unrealistic. Unless otherwise specified, all canning books assume you live at or under 1,000 feet of altitude. Considering that the larger part of the US landmass is at or under 1,000 feet altitude, this is a reasonable assumption. The good canning books (Ball Blue Book, others) include a calculation table for those who live 1,000 feet or more above sea level. You should check it out some time, if you never have. A typical pint of jam, processed without altitude adjustment takes around 15 minutes in a water bath. Pretty reasonable, no? When I lived in WI, I made jam by this method every summer. It was awesome jam. If you look at the altitude adjustment table in the Ball Blue Book, you find that the same pint of jam requires 40 minutes of processing time in a water bath. Forty minutes, the initial 15 minutes plus 5 minutes for every thousand feet above 1,000 for a total of 25 additional minutes. Add 15 to 25 and you find yourself monitoring a bubbling water bath for 40 minutes. I have a life that includes 3 children and copious amounts of time out of this house doing things together. It does not include time for high altitude water bath canning. And that's just water bath processing for high acid foods. Low acid pressure canning is even worse. Let's use potatoes, since I've done potatoes and remember the figures well. Quarts of potatoes requires 45 minutes at 15 pounds pressure, when done up at or below 1,000 feet of altitude. Add 10 minutes for every thousand feet (50 minutes), add to the original 45, and we're looking 95 minutes processing time. If I didn't have time for 40 minutes of water bath-ing jam, I most certainly do not have time for 95 minutes of hold a canner precisely at 15 lbs pressure (on an electric range, this is much more challenging than it initially sounds).
Given the time and energy efficiency issues at hand, I prefer dehydrating and fermenting. Fermenting is far more fun, plus, I already have detailed pictures, so that's what I'm doing first. Virtually anything can be preserved by fermentation, although some foods, like green beans, should be briefly cooked (par boiled) before preserving. If you're Paleo, you're probably not eating enough green beans to have even considered putting them by. If you're WAPF, take head of the phytic acid issue in regards to dry beans, be aware that fermenting will increase phytic acid in raw green beans, and par boil them for 30 seconds to a minute before packing in brine. I especially like doing garlic because there's no cutting, slicing, or dicing involved. You can fully peel the garlic or leave the wrapping on, I leave it on for the color the paper gives to the brine and the garlic cloves.
To put up 1 pint of preserved garlic, you will need 4 to 6 heads of garlic. I have a tendency to buy the 2 lb bags from Costco, pull a head or two for immediate use, and put the rest into pint jars immediately. Saves a lot of wasted cloves that decided to grow on me.
Shell all the loose paper off. If you want to keep the hard peel on the garlic that saves a great deal of time but a lot of people like to take it off before fermenting. Pack as tightly as you can into pint jars.
Use sea salt, any brand you like. But use sea salt that is free of iodine supplementation and anti-caking agents. Iodine can inhibit the fermentation process, leading to spoilage. Anti-caking agents can cause cloudiness in the brine. One of the indications of spoilage you'll be looking for later on is cloudy liquid so don't confuse the issue with poor quality salt.
With distinct vegetable pieces like garlic, I add the salt to the top of the jar and tap the jar on a hard surface to distribute throughout. Use 1 Tablespoon per cup. If your container is a pint, 2 T; if you're using a quart, 4 T, and so on. Depending on the exact environment you're going to store the jars, you may be able to use less salt, might possibly have to use more (unlikely but keep it in mind). Salt is used to inhibit the grow of bad bacteria in the first few days of fermentation, before lacto-bacillius gets itself going. If your storage area is quite cool (in the mid 60's down to around 54 F), you need less salt, but the fermentation will take longer (cold also inhibits the growth of lacto). If your storage area is fairly warm (70's into the 80's F), you will need the amount of salt described here, possibly a little more. Heat spurs on lacto-bacillius but also encourages growth of negative organisms as well. Should you find the finished product is adequately preserved in the environment you use, but tastes too salty, soak the vegetable in warm tap water for 5 to 20 minutes prior to use.
When the vegetable is packed in and salt added, fill with filtered water. Chlorine, as you might expect, can interfere with the growth of lacto-bacillius. Chlorine and various other chemicals added to tap water can also cause cloudiness. Since cloudiness, as previously mentioned, can be an indication of spoilage, you want to avoid using ingredients that may cause cloudiness separate from spoilage. Sea salt and filtered water please!
Try to get rid of as much air as you can. Lacto-fermentation is an anerobic process, meaning it grows in the absence of oxygen. Air bubbles slow things down and can spoil your jar altogether.
Despite the detailed information about containers that you will find in books such as Wild Fermentation, you can ferment safely and reliably in canning jars. Pack full, fill with water. Turn the lid as tight as it will go and the release by 1/4 turn. This leaves room for gases to escape but does not allow additional air into the jar. Garlic should sit in a cool dark place for about 2 months before using. Once you open the jar, keep in the fridge. It should last pretty much indefinitely in the fridge as the mark of proper lacto-bacillius fermentation is the ability to keep for long periods of time at cool temperature.
As far as determining spoilage, the best indication is smell. If something goes bad (and things will go bad sometimes no matter what you do), it will smell like a rotting pile of produce. You will not want to touch it with a 10 foot pole. Sometimes, you will find a layer of mold or very soft vegetables at the top. Most of the time, if you remove the spoiled layer, you will find perfectly safe-to-eat vegetables underneath. If you EVER find jars with buldging lids, don't investigate further and simply throw out the contents. Bulging lids are often a sign of botulism contamination and if you're not aware of botulism in home preservation, you should be afraid. Very, very afraid. Botulism can put you in a coma in less than an hour and there's less than a 10% chance you'll wake up from that coma. If you're not already familiar with home food preservation, make sure your jars are clean, your lids are clean and undamaged. You don't need to sterilize but I always wash jars in hot soapy water just before I start a fermentation process. Be smart and careful and all will go well