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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: Not Everything on the Internet About Mason Jars is True

May 7, 2026

Canning Basics: Busting more Mason jar myths MYTH: Canning jars can be sterilized in the oven. Canning jars can even be used for baking. No and no. Canning jars are made from annealed glass and are not designed for the dry, fluctuating heat of an oven. These conditions can cause…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Observe the 2-Hour Rule

May 14, 2026

Keep perishable food safe by observing the room temp time limits. One of the basic maxims of food safety is keep hot foods hot and cold foods cold. Not keeping perishable food hot enough (at or above 140°F) or cold enough (at or below 40°F) allows bacteria to multiply quickly, causing the food to…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Only Certain Fruits May Be Safely Canned for Baby

May 14, 2026

Be extra cautious preserving your own baby food. Want to preserve your own baby food? High-acid fruits are the only food for which there are home processing recommendations for use as baby food. Unfortunately, there are no recipes for canning pureed or mashed vegetables, meat or poultry. …

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Pressure Canning in Electric Pressure Cookers is Unsafe

May 6, 2026

Canning Basics: Research disputes manufacturers' claims regarding safety. Electric “multi-use” pressure cookers are all the rage these days, with good reason. One simple device can be used for many cooking applications, saving time and energy (as well as other benefits). Unfortunately, despite…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Prevent Botulism with Proper Canning Procedures

May 6, 2026

Low acidity, a lack of oxygen, moisture and moderate temperatures are a perfect storm for toxin production. Home canning is about more than creating a quality, shelf-stable product. When it really comes down to it, the home canning process is about making a safe product. That goal entails…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Prevent Browning by Pre-Treating Fruit before Canning

May 6, 2026

Keep your canned fruit looking light and fresh. Many light-colored fruits, as well as the stem-ends of cherries and grapes, can discolor and darken when exposed to oxygen. To retain good color and flavor when canning fruit, use high-quality fruit at the proper maturity, and place prepared (peeled,…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Pros, Cons, and Limitations for Canning Fruits & Vegetables

May 11, 2026

What does "hot pack" vs "raw pack" refer to regarding canning produce? Hot pack and raw pack refer to the method of packing food into jars prior to canning. There are advantages and disadvantages to each method; when both options are given, the one you choose comes down to personal preference…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Pumpkin Butter is Unsafe for Canning

May 6, 2026

There are no safe methods for home canning pumpkin butter. Pumpkin butter is a delicious autumn fruit spread that many folks love to preserve and sometimes give as gifts for the holidays. While canning pumpkin butter was once common, decades ago scientific studies found safety issues with the home…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Re-canning Commercially Canned Foods is Not Recommended

April 30, 2026

Buying large to break down into small is not practical and possibly unsafe. Buying large tins of canned foods, such as tomatoes and vegetables, can certainly save a lot of money, but not if you can’t consume the product before it spoils. Buying in bulk with the intention of breaking the contents (or…

UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Remove Foil from Baked Potatoes Immediately for Safety

May 14, 2026

Baking potatoes in foil is a safety concernBaking potatoes in aluminum foil is a common way of preparing this root vegetable. Doing so makes the skin soft, and some say that it makes the potatoes cook faster. The foil can also keep the potatoes hot longer once they come out of the oven – and this…