For the first time in my life, I am pretty settled and live in a house where I have my own garden. This, plus my undying DIY spirit have prompted my desire to finally learn how to preserve and can my homegrown harvest.
Not wanting to venture into this task all by my lonesome, I thought it would be advantageous to can with friends who had previously done it, thereby making them experts on the techniques and methods, able and willing to pass along their skills and knowledge to me through a hands-on, "quilting-bee" style of teaching.
Both times that I employed this method of learning from my presumable expert friends, we did not have the proper tools, ingredients, or recipes, nor did any of them have any more than a vague notion of what the canning process was supposed to be like. This was a great learning experience, but more along the lines of "what NOT to do" while canning. Although the end results in both cases were semi-successful, I concluded that the only way I was going to learn how to can was to purchase a canning book with exact recipes and explicit instructions.
Fortunately, and coincidentally, there happened to come along a Canning Workshop (free, no less!) at the Seattle Tilth's Harvest Fair over the summer, taught by the enthusiastic and knowledgeable Jessica Dally of the Seattle Free School. Jessica is a true "expert", having been certified as a "Master Food Preserver", and dedicated most of the class to food safety and prevention of food-borne illness. While this was not a "hands-on" class, and the students did not get to do any actual canning, I left the class feeling confident that I could take on any canning challenge that came my way.
For anyone else who may have a desire to dabble in food preservation, I thought it would be neighborly of me to pass along some of the tips that I learned from the workshop, and some that I learned from my trial-and-error experiments with friends:
1) Botulism is the Most Deadly Toxin Known to Man!
Botulism is a microorganism that, in itself is harmless and all around us every day. It is when the spores multiply in mass quantity in an ideal environment (low acid, anaerobic conditions, such as an improperly canned jar of string beans), and then release a neurotoxin as they die off, that they become dangerous, causing serious illness, neurological malfunction, and death. In addition to being microscopic, it also has no odor, color, or taste, so it is not detectable to the naked eye (or nose or mouth)! This is not something that you want to mess with! No one wants to die by eating a jar of asparagus that was canned by well-meaning, sweet Aunt Pearl who was unaware of the dangers of microorganisms and food safety. Jessica's goal was to scare us all into practicing proper canning procedures, and I would say that she accomplished this, at least with me. If you are not convinced and think we are being a bunch of worry warts or overly cautious old biddies, I recommend doing your own research on the subject.
2) Only Use and Follow Approved Recipes
Although it's impossible to tell if botulism is present in any jar of improperly canned food, it is possible to control and kill this and other microorganisms by cooking and processing the food and jars to a specified time and temperature. That's what canning is all about. Approved canning recipes are those that have been commercially and scientifically researched and tested to meet the proper acidity levels and heating times and temperatures to successfully kill or prevent growth of harmful bacteria, molds, etc. (FYI--other types of molds are visible, and/or smelly, and sometimes the lids will pop off if contamination is present--obviously, these foods should not be eaten!)
Two of the approved recipe books mentioned in class are: "The Ball Blue Book" (as in Ball canning jars) and "So Easy to Preserve", put out by The National Center for Home Food Preservation of the University of Georgia (one of, if not the only, school in the country where you can still get a college degree in Home Economics!). Books should be the most current edition, as recipes often change with more research and new knowledge and testing methods.
The Ball Blue Book has a 2009, 100th Anniversary edition available now. If you can find it locally, it should cost around $8-$10. Otherwise, it may cost you twice as much, as the shipping charge at most of the online retailers seems to be about the same or higher than the cost of the book. I ended up ordering mine directly from Ball. At $5.49, it was the least expensive copy I could find online, but even there the shipping was more than the book--$6.95! But even spending $12.44 is well worth it, considering there are over 500 recipes, plus detailed information and instructions on canning procedures. (I later found a copy at two local hardware stores for $10, so I recommend checking there first.)
So Easy to Preserve can be purchased directly from the University of Georgia for a total of $18, which is also much cheaper than you will find elsewhere online. (If you order two or more, they are only $15 each, so you might want to pick one up for a friend.) Unfortunately, they do not have an online ordering system. You have to print out the order form and mail in your payment. They do accept credit cards, but I chose to send a check--if they're going to have an old-school style of ordering, then I am going to use an old-school form of payment.
3) Water Bath Canning Vs. Pressure Canning
Most fruits are high acid, which means they are not a suitable environment for botulism. If Mrs. Crabtree from down the street presents you with a lovely jar of strawberry jam for Christmas this year, it is most likely going to be safe to eat it. High acid foods can be processed in a boiling water bath canner, as the temperature of boiling water is sufficient to kill any dangerous microorganisms in most fruits. Water bath canning is a pretty simple procedure, which is why my expert-canner-friend experiments were not complete failures. It is still important to follow recipes and process according to the instructions, which should give you a highly successful canning experience.
It is not necessary to purchase a special water bath canner, and if you have an electric stove, don't even bother with one. The ridged surface on the bottom of specialized canners causes uneven heating, which could negatively effect your processing. All you really need is almost any large cooking pot with a smooth bottom, and a rack that fits inside to keep the jars from sitting on the bottom.
Most vegetables, on the other hand, are low acid. And you know what that means, right? A perfect breeding ground for Botulism! This is a job for the Pressure Canner, which is a little trickier to use, but once you get the hang of it, you'll want to can everything you can get your hands on. A pressure canner gets the water hotter than boiling, which is necessary for killing microorganisms in low acid foods (with the help of adding extra acid to the food in the form of lemon juice, vinegar, etc.). Be sure to follow your recipe exactly, and process for the correct amount of time, with the correct temperature and pressure.
Ms. Dally recommends using a weighted gauge pressure canner as opposed to the dial gauge style. This is because there is no guarantee that your dial gauge is calibrated correctly, unless you get it done professionally (and those places are getting more difficult to come by), and there is no way to tell if the temperature is staying constant without physically watching it for the entire processing time. Considering a recipe might call for one and a half hours of pressure canning, you could be spending a lot of time staring at that little dial. The weighted gauge, by contrast, lets you know it's working by steaming and rattling, causing a loud racket--thus giving you the flexibility to roam about the house, tending to other tasks while your canner is hard at work killing all that botulism. (Pressure canners can not be used on glass-top stoves!)
4) Adding Acidifiers
If a recipe calls for lemon juice or vinegar, it is important to use the bottled, store-bought variety, rather than squeezing a fresh lemon or using homemade vinegar. This is because the commercially available acidifiers have been tested to meet specific levels of acidity. Since the acidity level changes (goes down), as fruits ripen, there is no guarantee that the juice you are squeezing has the level necessary to meet the needs of the recipe. Some recipes will specifically state "store-bought lemon juice" or "vinegar with at least 5% acid", as a reminder, but you should get in the habit of keeping the store-bought variety of both on hand, if you plan to do any low-acid vegetable canning.
5) Essential Canning Equipment
Canning without certain tools can make for an inefficient and often frustrating experience. While it may be possible to can using kitchen gadgets that you already have on hand, such as salad tongs, or even tools from the garage (channel locks?), I can assure you that it is well worth the small amount of money that it will cost to purchase a few simple specialized tools. (It's possible to open a wine bottle using a screwdriver and hammer, if nothing else is available, but obviously it's much easier and faster to do with a cork screw.) Even if you are just trying out canning one time to see if you like it, I would recommend purchasing a canning kit that will include some of these essential items. You will be more likely to enjoy your canning experience with the proper equipment. And even if you decide you don't like canning, you can always find someone else who does, and will be happy to take all the equipment off of your hands.
Jars: The only jars that can be used for home canning are those that are specifically manufactured for this purpose (aka "Mason Jars"). They are designed to withstand the extreme temperatures and pressures that the canning process will put on them; and the edges are flat, suitable for the lids to form a proper seal and the rings to screw on nice and snug. The most common brand is Ball or Kerr, but other brands are also available such as Leifheit and Bormioli Rocco. (A brief history of canning jars can be found here.) Jars can be used over and over again, for many, many years, as long as they are kept in good condition. Be sure to check that the rims have no chips or nicks to ensure a proper seal, and check for hairline cracks in the body of the jar to avoid unnecessary breakage and explosions in the boiling water.
Lids: Canning lids are a two-piece system. First there is the sealing lid that covers the top of the jar and forms a tight, air-proof seal with the rubber coated ring on its underside. Then there is the metal band that screws on top, which holds the lid in place while it's sitting in a pot of bubbling water. Both pieces are essential to the canning process, but it is important to remember that the sealing lids are NOT reusable! Once a seal has been made, and then cracked open, it is a total crap shoot as to whether a proper seal will form again with a used lid. (Please re-read the Botulism section above if you want to know why this is important.) It is also important to note that all canned goods should be stored without the metal screw band. The bands should be removed once the lids have sealed and the jars have cooled. There are two reasons for this: 1) If there is mold or some other problem with the seal, you want the lid to be able to pop off if it wants to, so that you know not to eat that one--the screw band will prevent that from happening. 2) The outer metal screw band IS reusable. Once you take it off of your current project, you are free to use it for another batch of home-canned goodness.
If you purchase a set of brand new canning jars, the package will come with a corresponding number of two-piece lids. New lids can also be purchased separately, usually in packages of 12, and with or without the bands.
Jar Lifter: This simple, yet handy little device allows you to safely and quickly lift jars in and out of the hot water without burning your hands. (Trust me--doing this job with a set of salad tongs and an oven mitt is not fun!) I put this on the "must have" list.
Funnel: Since it is crucial to not have any food particles getting in the way of your seal, wiping any spillage off the jar rims will be a lot quicker and easier with this "must-have" tool. The wide-mouth opening of a canning funnel allows you to accurately pour your hot fruit sauce, syrup, or boiling water into a canning jar without making a huge mess.
I hope this information is helpful to any beginner canners. I plan to post more articles on my canning experiences in the future, with links to approved recipes and other info that I come across. Until then, this should be enough to get you started, or at least get you thinking about getting started, and preparing for the next harvest season.