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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: Cook Red Kidney Beans Safely to Destroy Toxicity

May 7, 2026
Cook them properly and not in a slow cooker! Red kidney beans are a healthy food – unless they’re not cooked properly. They contain a compound (“PHA”), found in many types of beans, and at especially high levels in red kidney beans. PHA can be toxic at high levels; in fact, consuming only 4 or 5 raw or…
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UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Defining Pressure Canner Capacity

May 6, 2026
Canning basics: The difference between volume capacity and jar capacity. Looking to acquire a new (or used) pressure canner? One consideration when evaluating whether a pressure canner will suit your needs is the size of the device. It’s important to distinguish between volume capacity and jar capacity …
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UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Don't Can Tomatoes from Frost-Killed Vines

April 30, 2026
Tomatoes from frost-killed vines are not for canning As the weather turns cooler and overnight temperatures dip, you may find yourself scrambling to pick the last of your tomato crop. If a frost kills the vines before you get to them all, are the remaining fruits safe for canning? The short answer is no…
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UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Don't Can Wild Mushrooms

April 30, 2026
Button mushrooms yes; wild mushrooms no. Mushrooms are a low-acid food. To be safely canned, they must be properly acidified (pickled) or processed in a pressure canner.There are other safety considerations as well: Only domestic button mushrooms may be safely canned. Wild mushrooms (whether wild…
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UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Eggnog Safety

May 12, 2026
Make eggnog only from pasteurized eggs.Eggnog is a seasonal/holiday tradition in many households, and while it can be purchased commercially, some people prefer to make their own at home. Can you do so safely?  For sure, but use only pasteurized eggs when making eggnog. Raw eggs can be contaminated with…
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UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Fill Them While They're Hot!

May 7, 2026
Canning Basics: Make sure your canning jars start hot and stay hot Canning jars should always be washed and rinsed well before being used. And while they don’t always need to be sterilized (unless the processing time is less than 10 minutes), the jars do need to be hot when filled with food, and kept…
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UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Freezing Cranberries is Easy

May 12, 2026
Tricks for preserving the highest quality of fresh cranberries. Cranberries are a wonderful fall fruit that are easy to preserve for use throughout the year. The very easiest preservation method is to simply store them in the fridge (refrigeration is preserving!), where they will keep for about 4 weeks…
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UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: Get Your Dial Gauge Tested Annually

May 6, 2026
Canning Basics: Annual test of dial gauge ensures accuracy. If you have a dial gauge pressure canner, its gauge should be tested annually for accuracy (pressure canners with weighted gauges do not need to be tested for accuracy).  Using a dial gauge that reads too high can result in under…
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UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: How to Calibrate a Food Thermometer

April 30, 2026
A thermometer is only helpful if it's accurate  A kitchen thermometer is one of the best tools to have on hand to ensure quality and safety when cooking and preserving. They come in a variety of types, from dial-stem meat thermometers to glass candy thermometers to digital thermometers with wireless…
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UC Master Food Preservers of Central Sierra: Article

Preserve it! Series: How to Determine the Gel Point for Jams and Jellies

May 12, 2026
Canning Basics: How to know that a gel will form when making soft spreads. How do you know when your jams, jellies, and other soft spreads are ready to remove from the heat? There are several tests that can determine that the gel point (aka gel stage) has been reached, including the sheet test and the…
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