Preserving Potatoes


Not known for their fragility, potatoes are a robust, starchy tuber in the nightshade family (along with fellow Solanaceae family members tomatoes, eggplants, and peppers). Potatoes pack a nutritional punch, weighing in with substantial amounts of potassium, fiber, protein, vitamin C, Vitamin B-6, Magnesium, and a lesser but still notable amount of Iron.

It’s easy enough to store fresh white potatoes for up to 2 months in a cupboard kept at 50-70°F (sweet potatoes last only 2-3 weeks). But what if you want them to last even longer?

potato masherInterestingly, storing white potatoes in a refrigerator is likely to diminish their quality and they are expected to last only 1-2 weeks there. Alternatively, you could cook and mash them, stuff them, or scallop them for freezer storage, but again, they will retain best quality only for a few weeks in the freezer.

Drying is an option for making potatoes last longer. Wash, peel, then cut potatoes into 1/4-inch thick shoestring strips, or cut into 1/8-inch thick slices. Steam blanch the prepared pieces for 6-8 minutes or water blanch them for 5-6 minutes. Plan for a drying time of 8-12 hours in a dehydrator and up to twice as long in an oven, depending on circulation. If you dry sweet potatoes and want to rehydrate them for a recipe, combine each cup of dried pieces with 1-1/2 cups water and let them soak for 30 minutes.

As for canning potatoes, our recommendation is to peel potatoes before canning. That style of preparation is how the research was carried out to determine the recommended processing, and in order to know that the peeling does or does not make a difference, research would need to be done with unpeeled potatoes. Different assumptions might be needed in assessing just how many spores of C. botulinum or other bacteria might be present at the start of the process and what amount of heat might be needed to meet standards for the risk of possible survivors. We do not know of research of canning potatoes with peels left on, so we recommend the preparation steps provided with the process recommendation, especially because there is a possibility that the deviation could result in a less safe situation. Also due to safety concerns, it is important to use potatoes that are only 1 to 2 inches in diameter if you are canning them whole.  These are sometimes described as “new” potatoes; the idea is to use less mature, smaller potatoes which tend to be less starchy than older, “grown-up” potatoes.

White potatoes for canning should be the “waxy” or “boiling” kind.  Different types of potatoes have different amounts and types of starches and they react to heating differently.  You want a potato that keeps its shape and texture well after a lot of heating, and not one that falls apart, becomes “fluffy” after cooking, and is better for mashing. Most red-skin potatoes are of lower starch than baking potatoes  and work well for canning. Many white round potatoes with thin skins fall into this category with red-skin potatoes too. Russets are not good for canning but are  good for baking (they have a high starch content).  Yukon Gold may not be the best potatoes for canning.  While they seem good for boiling, they do tend to fall apart when overcooked.  From what we have read, there is a wide variety in the types and amounts of starches in blue potatoes, so not all blues are the same, just like not all white potatoes are the same in these characteristics.

Sweet potatoes can be slightly larger, but medium-sized potatoes should be cut to fit in the jar in uniform-sized pieces. Note that the sweet potato pressure canning process time is significantly longer than for white potatoes.

Sweet potatoes can have a sugar syrup for canning, if you like that style. But otherwise, all potatoes — white or sweet — should have fresh, boiling water prepared to pour over the preheated potatoes.  Do not use the cooking liquid.  That cooking water contains a lot of starch that comes out of the potatoes and the process time was determined using fresh boiling water to cover.  The added starch can create  a safety problem by slowing down heating of the potatoes in the canner, and it also creates a very unappealing pack with possible masses of gelled or congealed starches around the potatoes.  If you have spoilage, this makes it very hard to see the signs of some spoilage.


potato cartoon




Have you got a cornucopia of corn starting to come in? Or maybe you just really enjoy crunching on fresh kernels from a grocery store? Well, if you want that great flavor to last, then try one (or all!) of these methods of preserving corn…

Instructions for freezing corn-on-the-cob, whole kernel corn, and cream style corn are in a previous post – Corn: On or Off the Cob.

If you’re wondering what to do with all those frozen corn kernels, or if you have 16 to 20 medium-sized ears, and you’re feeling a little zesty, then try making Pickled Corn Relish and processing it in a boiling water canner.

Corn in HuskThe rest of these canning recommendations are not pickled products, and so a pressure canner is required since corn itself is a low-acid food. Corn can be canned as Whole Kernel Corn or Cream-Style Corn. Sweet corn kernels may also go into a medley of Mixed Vegetables or Soup (note that the pressure canning process time varies – following the recommended process time is important to the safety of the final products…the soup has a lot more water to help distribute heat more quickly, and also less solids to have to penetrate through).

If your corn browns during canning, it usually means that the temperature required for canning is too high for the sugar levels in your corn variety.  This carmelization has become more of a problem as newer varieties of corn get sweeter and sweeter. You cannot safely reduce the heat or processing time needed for canning corn; you can freeze that corn or find a locally grown variety that is recommended for canning. Though not an immediate safety concern, you might want to consider refrigerating these jars and/or consuming them more quickly since they may not maintain the best quality for long.

popcorn kernelsCorn can also be dried, although consider your use of the kernels to decide if the texture is what you are seeking. Ears of popcorn can simply be left to air-dry on the stalks or at 130°F after harvest. For other varieties of corn, husk, trim, and steam blanch for 2 to 2-1/2 minutes or water blanch for 1-1/2 minutes. A test to check if it’s blanched enough is to cut into a kernel — if milk does not exude when the kernel is cut then it is adequately blanched. After blanching, cut kernels from the cob. Use a dehydrator try liner (or a cookie sheet if drying in the oven) so that the small pieces don’t fall through. Dry in an electric dehydrator at 140°F for 6 to 10 hours, longer in an oven. To rehydrate the kernels, soak each cup of corn in 2-1/4 cups water for 30 minutes.

Lastly, let’s not forget candy corn this time of year…it typically stores well on the counter in an airtight container (perhaps out of sight from children!).

candy corn

Putting A Lid On Green Beans

IMG_1110Having a green bean emergency?! So many questions came in over this summer about canning green beans that it seems time to discuss what is and is not recommended for the process. No one wants to be told that they under-processed their precious jars of homegrown green beans and need to discard them to be safe, but unfortunately we’ve had to break the news repeatedly.

Let’s first address the most common and critical safety concern with canning green beans: “I canned my green beans using a boiling water bath…is that ok?”

Oftentimes upon the advice from a grandmother or neighbor, people make an attempt to can their green beans using a boiling water canner. BOILING WATER CANNING IS NOT A SAFE OPTION FOR GREEN BEANS. While stories may be told of how they’ve done it for years and never gotten sick, the risk of botulism is ever present in canned green beans that were processed in a boiling water canner. Such beans are under-processed, not having received a heat treatment at a high enough temperature to destroy the toxin-producing spores of Clostridium botulinum. The concern is real: under-processed green beans caused two outbreaks of botulism in the United States in 2008 and 2009.

The only process we support for canning green beans is using a pressure canner. Here are our recommendations for Canning Green Beans. The process itself is simple – wash, snap, boil, fill, process – but the use of a pressure canner is absolutely critical to ensure the safety of the beans. The pH of green beans (5.7 – 6.2) is well above the cut off that can be processed in a boiling water canner (4.6 or below).

IMG_4675If you do not have a pressure canner and do not plan to get one, you do have the delicious option of canning Pickled Dilled Beans in a boiling water canner. This recipe has enough vinegar that the overall pH of the product lowers to the safe zone for boiling water canning – also called acidification, or pickling. Don’t like pickled products? Try freezing your green beans or even drying them into a snappy snack!

What’s In Your Choice Salsa?

Salsa Easy to make and simple to can in a boiling water canner, salsas are very popular for home canning. One of the most common requests we receive at the National Center is “Can I can my salsa recipe?”

The answer is not what people usually want to hear…but the trouble with canning your own salsa recipes is that most recipes contain low-acid ingredients, and low-acid foods need to either be pressure canned or properly acidified by the addition of a strong acid (like lemon juice or vinegar) for boiling water canning. Either way, a process time needs to be determined for any particular recipe to ensure that spoilage or sickness-causing microorganisms will be destroyed (this time varies based on qualities like pH, solid-to-liquid ratio, size and shape of jar, etc.).

So then, we cannot recommend that just any homemade salsa recipe be canned. That’s why we have a variety of carefully tested salsa recipes for you to choose from. Safety first, but also quality, were given priority in developing these recipes, so we hope you will find at least one that you like. recipe cardCrushed tomatoes

If the idea of following a recipe exactly is tough for you to swallow, then, well, you might want to consider taking up cooking instead of canning, but for now, you might also enjoy playing with our Choice Salsa recipe. This recipe was developed to allow for a great deal of flexibility – you can use any variety of onions and peppers so long as you use a total of 9 cups diced onions and/or peppers per batch. The only other ingredients you need are 6 cups chopped tomatoes, 1½ cups bottled lemon or lime juice, and 3 teaspoons canning or pickling salt. Remember to enjoy some fresh and refrigerate jars after opening!