Master Food Preserver Week 4 - Canning Acid Foods

StrawberriesI just had my last Master Food Preserver Class but I'm not up to date on reporting on each class so I'll report in sequence even if the class was actually a couple of weeks ago.

The fruit is about to arrive from Greenbluff and Yakima so let's talk canning low acid foods.

We learned that the key to sorting out what method of canning to use is the acid level of foods. Foods higher in acid with a pH 4.6 or lower include rhubarb, apples, grapefruit, blackberries, strawberries, raspberries, blueberries, sweet cherries, pears, and apricots. Note: the lower the pH the higher the acidity. These foods are safe to can using the water bath method using a recipe from here, here, or here. Note that the growth of molds can reduce the acidity and move fruits into the low acid category and make them susceptible to the growth of botulism. Go here for help choosing the right set-up for canning.

Tomatoes have a pH that ranges from 4.0 to 4.6, and because of this borderline status of acidity they must be acidified before processing with either bottled lemon juice (1 tbs/pint or 2 tbs/qt), citric acid (1/4 tsp/pt or 1/2 tsp/qt) or vinegar of 5% acidity (2 tbs/pt, 4 tbs/qt). Note that acid must be added whether you are using a boiling water bath or a pressure canner. The state of Washington extension office recommends boiling canned tomatoes for 10 minutes before eating as an extra measure of caution against botulism poisoning. Please note that canning times have changed recently for tomatoes, so  make sure to use an up to date version of recipes available here, here, or here   

Random notes on safety and quality: Make sure to adjust water bath time for altitude. Steam canners have major problems and are not recommended as a replacement for water bath canning. Vacuum packing machines are not a substitute for heat processing home canned foods. Use jars made for canning and lids with screw bands. Using metal scrubbers to clean jars can weaken them and lead to breakage. Screwing the band on too tight can lead to the lid buckling. Hot packing is generally recommended for improved quality. Check your appliance manufacturer's recommendations before you can on your ceramic stove stop. It is not considered safe to can quick breads. It is also not safe to home preserve veggies in oil, so throw out that garlic in oil your cousin gave you and that oil that you added peppers to last summer for the fun of it. The oil creates an anaerobic environment which can lead to the growth of botulism toxin. Some thing we see in the store we can't safely prepare in the home. 

Links:
Canning Fruits pdf
Canning Fruits and Tomatoes ($2)
How Do I Can?
How Do I Can Tomatoes?
How Do I Can Salsa?

The information in this post is taken from the Master Food Preserver Class taught by Washington State Extension in May and June of 2008. I will soon be dubbed a Master Food Preserver which I will put right up there with my Master of Divinity.