Aldona Bird, Contributors, Latest News

USDA guide make scanning much safer

For Christmas last year my sister gifted me the USDA Complete Guide to Home Canning. I’ve only used a few recipes from it, but it has changed my outlook on canning.

Pre-recipe book, I was cautious but fairly comfortable with water bath canning. I started about eight years ago, canning whole tomatoes with my mother. Then I canned apple sauce with her.

I felt safe with these — the high acidity and sugar (respectively) keep them safe from growing botulism. I’d look up the processing time, and that was about it.

Although both of these ingredients are fairly safe, new recommendations are either to measure the tomato pH or add acidity, as some fall below acidity level considered safe for canning.

My sister and I have speculated about this, and wondered if lower tomato acidity might be due to hybridization selection for sweetness. The volunteer cherry tomatoes in my garden this year were much more sour than the sun golds I planted.

Whatever the case, I never added acidity to my tomatoes in the past. After reading through the recipe book and the many cautions to add lemon juice or citric acid, I plan to buy a few pH test strips — just to be sure that extra acid is necessary for my tomatoes.

Another instruction I never followed too closely was measuring the headspace. Headspace is the air left at the top of the jar between the food and the lid. Leaving room for food expansion and vacuum formation as the jars cool, thus sealing the lid.

I eyeballed and estimated the headspace. I’m sure I got it wrong, as it isn’t easy to guess at a quarter-inch vs. half an inch of space at the top of a glass jar. Now I use a canning funnel with the headspace measurements marked.

I love this tool. Although, before I started using it, none of my jars exploded, I did have better luck with most of my jars sealing well this year though. I wonder if I can attribute that to more headspace precision.

So far this year I’ve canned a few jars of whole tomatoes, many jars of salsa, pickled jalapenos, pickled banana peppers and tomato sauce. Not nearly done with my canning for the season — I have more tomato products to preserve, along with apple sauce and maybe some other fruit recipes.

I’ve found myself being more concerned with precision in following recipes now that I have a recipe book. Last year when I made salsa, I followed a recipe I found online (which said it was USDA approved). I added some extra amounts of some ingredients — to compensate, I added more vinegar too.

Logically, I do think this was safe, however this year I followed the recipe exactly.

Becoming more compulsive about canning, I need to keep in mind that even the USDA changes its canning rules. My sister has a USDA recipe for tomato sauce with veggies, formerly approved for water bath canning. Now the same recipe says to use a pressure canner only.

With all the rules to follow for preserving food safely, I’ve found myself wondering a few times how humans have survived as long as we have. Even with everything we know now about canning and food safety, people still get botulism each year. Granted, in 2021 only 31 people in the U.S. got botulism, but still. Even though we have an antitoxin, I will continue to follow the current recommendations for canning.

ALDONA BIRD is a journalist, previously writing for The Dominion Post. She uses experience gained working on organic farms in Europe to help her explore possibilities of local productivity and sustainable living in Preston County. Email