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UC Master Food Preservers of Central Sierra

Preserve It! Series!

Formerly the UC Master Food Preserver of El Dorado County's Preserve It Poster series, this is a collection of answers to frequently asked canning, preservation, and food safety questions.

If you don't find your answer here, reach out to your local Cooperative Extension Master Food Preservers.

In El Dorado County, California, the best way to do that is with the Ask a Master Food Preserver link.

Ask a Master Food Preserver

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: "Dry Canning" Dried Foods is Not Actually Canning, and Potentially Unsafe

May 12, 2026

Internet practice is not a recommended preservation method. Another preservation process making the internet rounds recently is so-called “dry canning,” in which dried foods such as beans, grains, pasta, nuts, flour, etc. are put into canning jars and then the jars are heated in a low oven. Some…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: "Dry Canning," an Internet Sensation, is Inherently Dangerous

May 12, 2026

Dry canning vegetables doesn't ensure even heating. Another “homemade” canning method (in other words, someone made it up themselves) has been making the internet rounds recently, which involves pressure canning vegetables without any added liquids. The food, either cooked or raw, is simply put in a jar…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Acidifying Tomatoes

April 30, 2026

Added acid is always required when canning tomatoes Once upon a time, tomatoes were considered a high-acid fruit. But research has since shown that they are, in fact, variable in acidity, with pH levels sometimes going higher than 4.6, the dividing line between high-acid and low-acid foods – and the…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: All Salt is Not the Same

April 30, 2026

Salt is salt is salt - except when it's more than salt Salt is an essential mineral for health and one of the five basic human tastes. It’s indispensible in the kitchen for many reasons beyond taste. Whether gathered from coastal or inland salt pans, evaporated from sea water, or mined from salt…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Baking in Canning Jars is Unsafe

May 7, 2026

Canning Basics: Canning jar manufacturers specifically recommend against using their jars in the oven. Baking in canning jars (aka mason jars) is an unsafe practice, despite those cute pictures of miniature pies and cakes you see on the internet, especially around the holidays. Why? Canning jars are not…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Blanch Vegetables Before Freezing

May 12, 2026

Blanching is an important step for vegetable quality. Blanching is a heat process in which vegetables are scalded in boiling water or steam for a brief (but specific) amount of time. It is a very important step in the freezing procedures for most (but not all) vegetables. Blanching stops enzymatic…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Bubbles in Canning Jars Can Be Bad News

May 14, 2026

Distinguish between bubble types to determine safety.It’s not uncommon to see tiny bubbles in glass canning jars; these are generally not a concern. But large bubbles in the glass are manufacturing defects. They indicate weak points in the walls of the jars which could spell trouble during the canning…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Can Cheese Be Frozen (and Still Taste Good)?

May 12, 2026

Hard cheese freezes best, others less so. Cheese is best stored in the refrigerator, but there are some cheeses that freeze fairly well, especially hard or semi-hard cheeses. Good choices for freezing include Cheddar, Edam, Muenster, Parmesan, Provolone, Romano, and Swiss. Some softer cheeses such…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Can You Make Jelly from Store-Bought Juice?

May 12, 2026

Commercial juice is an easy and convenient option, but...Yes, you can certainly make jelly from commercially prepared juice (either bottled or frozen). It’s faster and easier than extracting your own juice from fresh fruit. There are a couple of things to keep in mind, however. The juice should be…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Canner Gauges May Be Affected by Improper Storage

May 6, 2026

Canning Basics: If sub-zero, separate the gauge before storing the canner. There’s no question that a pressure canner can take up a lot of cabinet or pantry space. As it’s an appliance that typically is not used on a daily or very frequent basis, many people opt to store their pressure canner in a…