Understanding pH Levels: How it Effects Canning

I love chemistry so this is one of my favorite lessons for new canners.

Currant jelly, pickle chips, and pickle spears all processed 

in a waterbath canner

If you have had any experience canning, you have probably read or heard something about pH or acid levels in relation to safe canning methods. Or, you have at least probably heard that some items are not safe to can in a boiling waterbath. This post breaks down why. 

When you preserve something in a waterbath canner, you heat the jars and their contents to the boiling point (that temperature varies depending on your elevation, but at sea level the boiling point is 212 degrees F). That heat is enough to kill the micro-organisms that can cause spoilage, mold, or fermentation, but it’s not enough to kill botulism spores (they require far higher temperatures). The process of boiling the jars also helps to drive the oxygen out of the jars, creating a vacuum seal. For jars that have sufficient acid content, the result is a jar of food that is safely preserved and shelf stable.

If a food is 4.6 pH or lower, it can be safely canned using a waterbath method. It it is 4.7 or above, it is considered too alkaline to waterbath process and must be processed using a pressure canner method. 

If a food is very close to the 4.6 pH range, you can often add acid to make it safe. For example, adding vinegar or bottled lemon juice can bring a pH down. Tomatoes are usually right around 4.6 pH, so when I can them in a waterbath, I add bottled lemon juice. NOTE: It is important to use bottled lemon juice rather than juice from fresh lemons because the pH is monitored and guaranteed in manufactured juice, whereas fresh lemons vary in pH. It is the same with lime juice. Vinegar used for canning is usually labeled as either "safe to can" or has at least 5% acidity. 

Some foods are naturally acidic, such as peaches, or are made acidic by the recipe, such as pickles. Almost anything pickled is safe to can using a waterbath because of the vinegar brine. Most fruits, jams, and jellies can also be safely canned using a waterbath method. 

When in doubt, you can always use a pH meter. Keep in mind you are measuring the contents of the entire jar and not just one ingredient. For example, if you know tomatoes are 4.4 pH, but you add onions, peppers, and spices, then you have raised the pH and you should either balance it with lemon juice or acid, or pressure can to be safe. 

Waterbath Canning vs. Pressure Canning

There is a difference in waterbath canning and pressure canning.

Waterbath canning involves a process where you place your hot jars in a big pot of boiling water. The water has to cover the jars completely and boil during the process time. A Pressure canner is a large pot with only a couple inches of water in the bottom. The lid screws or bolts on, there is a pressure gauge, a steam valve, and other safety mechanisms to avoid excess pressure. The pressure from the heat on the stove will cook the food. Waterbath canners have the ability to heat jars to 212 degrees, that of boiling water. Pressure canners get much hotter, and can kill harmful spores. Before canning, read my blog post on acid and pH levels and how it determines which process to use.

Everything can be safely processed in a pressure canner, but not everything can be safely processed in a waterbath. When in doubt, pressure can.

I always get asked, "Then why would everyone pressure can all the time?" There are several reasons:

1. Purchasing a waterbath is fairly inexpensive, whereas pressure canners are spendy. I have a Graniteware Waterbath  from bi mart that I have used for several years that was about $11. My Presto Pressure Canner was about $100.

2. Waterbaths are low maintenance. They last forever. With pressure canners, it is important to check the gauges and seal often, and sometimes those components need replaced. It's not expensive, but waterbaths are good to go for about 150 years.

3. Pressure canning can be scary for people who have never done it. Everyone has seen those disaster photos and read the stories on the internet about explosions and people getting burned, etc. Waterbath canning is the same as boiling water, and poses much less risk. People tend to be less intimidated by waterbath canners.

4. When people start out canning, typically they are canning easy foods, like whole fruit, jam, or salsa. All of these things can be done in a waterbath, so that's where most people start. It's hard to switch to something more difficult for some.

However, there are pros to pressure canning:

1. Everything is done much quicker. Something a waterbath would take 45 minutes to do, a pressure canner can finish in 10.

2. You can double stack easier in a pressure canner. Although you can do it with a waterbath too, it gets difficult to measure the water to the right height, etc. While pressure canning I can get two batches done at once.

3. Using my pressure canner doesn't require boiling a huge pot of water, so my house is not hot and sauna like (canning season is smack dab in the middle of summer).

I prefer pressure canning usually, but sometimes I break out my waterbath to do some items, like pickles (pressure canning is too hot and causes them to be mushy).

Always follow the instructions on the recipe you are using. If it says use a pressure canner, use one. If it says waterbath, you can usually substitute pressure processing without problems. Make sure each recipe is from a credible source and is tested. 

Canning Basics

Each year during canning season I have so many requests from my friends to either teach them to can or to make a video (haha... no) on how to can. I can almost everything- jams, jellies, fruits, tomatoes and salsa, pasta sauce, tuna, and vegetables- and I have been canning pretty much my whole life. I think I have made every mistake there is to make, seen every disaster that could happen, and have had to throw out whole batches because of "mess ups". Canning is not difficult, but has to be done properly and per guidelines to keep it safe.

This blog post is just the basics for beginners to learn what to do and not to do when canning. If you follow the basic rules, you'll have great outcomes each time. 

1. There is a difference between waterbath canning and pressure canning. Before canning anything in a waterbath, read my blog post on Waterbath vs. Pressure Canning here. 

2. Make sure you use new lids each time. Jar rings can be reused over and over again until they are rusty or bent, but new lids must be used or a proper seal wil not form. 

3. Prior to sealing any food, you should sterilize your jars by running them through the dishwasher. If you don't have a dishwasher, wash them in hot, soapy water and rinse with hot water. 

4. Lids and rings should also be sterilized. You cannot put lids in the dishwasher. I clean mine by boiling them for 2 minutes. 

5. "Headspace" means the space on the top of the jar between the product and the lid. Recipes will specify a headspace. Pay close attention and follow the instructions. Leaving too little headspace can prevent sealing or cause product to "escape" or leak out during processing. 

6. Learn to adjust for elevation. When using a pressure canner, most recipes will say something like "Process at 10 psi for 10 minutes". The higher your elevation, the higher the pressure must be. The FDA has a handy website with these instructions. 

7. Get a pH meter and use it. It's important to know what the pH is on certain foods to determine whether you can use waterbath processing or not. 

8. When measuring pH, keep in mind that you are measuring all of the contents of a jar. So, if you are canning tomatoes, but you add onions, peppers, and spices, the pH will change from that of just tomatoes. Remember, 4.6 or lower, waterbath is ok. 4.7 or higher, only pressure canning is safe. The FDA has a guideline chart if you need some help. Before canning, please read my post on safe pH levels here. 

9. Follow the FDA and canning guidelines always.

10. If a recipe uses vinegar or lemon juice, use the specified amount. Do not skimp. Vinegar and lemon juice are used to make jars acidic to kill harmful bacteria and botulism spores. If not prepared correctly, waterbath canning will not kill botulism spores, which can be harmful. 

11. Always label your jars with the name of what it is, the date you canned it, and a batch number. Batch numbers come in handy. If I make two separate batches of dill green beans, both in July 2016, and one batch was too salty or bitter, I know which cans to throw out and which to save. Similarly, if I make one really kick ass batch of salsa, I know why, and I know I can recreate it. Batch numbers rule. 

12. Store jars in cool, dark places. I keep mine in my food pantry. Basements are a popular storage space. Keep out of sunlight, which can heat and brown fruits. My grandmother had some jars in her laundry room, and because of the heat, several seals popped. It was a huge mess to clean and a shame of a waste.

13. Wear an apron. Don't ruin your clothes.

14. Wear clothes toed shoes. Trust me. A hot, heavy jar is not friends with your feet. Ouch. 

Holy Cow- It's Been too Long!

I got an in blog email from a follower asking if my page was still active.

How embarrassing!

Of course. I have been so busy lately that I have not thought about posting recipes. Now that I've had a kick in the pants from a faithful foodie, I will get back on the horse.

I took a break from writing recipes to go to school. First, it was Phlebotomy and Lab Technology. After that wasn't enough, I did a Dialysis Technician Program (I currently work as a hemodialysis technician). I am now studying to be a nurse. Along the way I have accidentally earned a few random certificates (Medical Office Assistant, etc). I think I may start a collection ;-)

My husband and I made it "official" and after ten years, finally legally tied the knot. Shortly thereafter we bought a house which we are working on to make "our own". We have had it painted, we landscaped, planted some gardens, and we plan on adding a deck and a bedroom. Easier said than done, right?

After buying the house, we gave in and finally got our kids a dog. His name is Norman Bites, and he is the cutest Jack Russell Corgi mix. High maintenance he may be, the boys love him and he loves them.

I have found time to volunteer in my son's classroom and although I'm not coaching this year, the boys are enrolled in summer soccer. Each weeknight we have some sort of soccer event, and we love it.

In all of the chaos of working, school (Dean's List! Whoop!), I am proud that I still find time to make a home cooked dinner each night for my family. Sometimes I don't have time to curl my hair or wear makeup, and I haven't painted my nails in a while. My eyebrows need attention and that "exercise program I was doing- ha. But, my family sits down to a set table and eats a healthy, homemade dinner every single night. And I love it. I wouldn't have it any other way.

Last weekend I overheard my 11 year old stepson tell someone "Lexi is Supermom. She can do everything. It's like the moms on TV." Aww. My heart skipped a beat. He had no idea I could hear him <3 6="" be="" guess="" have="" i="" if="" interjected="" more="" my="" nbsp="" old="" on="" p="" popsicles="" provided="" quickly="" say="" so="" super="" that="" to="" will="" work="" would="" year="">
So, in a long response to one of my favorite blog followers, yes, my blog is active, just not as active as I am. Within the next week or so, I will find the time between Medical Terminology assignments to write down one of the dinners I make and share it with the world.

By the way... 20,000 views. You guys rock! <3 nbsp="" p="">