Problems with Food Preservation

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Photo courtesy The Countryman Press
Lacto-fermentation is one of the oldest forms of food preservation. It is the process that turns cucumbers into classic deli dill pickles and cabbage into sauerkraut.

Leda Meredith has been preserving food since she was a child at her great-grandmother’s side, and she covers all aspects of the many styles of food preservation in her book Preserving Everything (The Countryman Press, 2014). In this excerpt from chapter 13, “Troubleshooting,” she addresses the many issues that one may encounter when lacto-fermenting, canning, pickling, making jams, dehydrating and cold storing.

You can purchase this book from the MOTHER EARTH NEWS store: Preserving Everything.

Lacto-Fermentation Foes

Fermentation never begins, or the food spoils even after fermentation seemed to start

If after 1 to 3 days at a room temperature (somewhere between 60 and 85°F), your ferment still hasn’t started fermenting, you may have to compost it and start over. Definitely if the food smells bad (it should have a lightly sour smell when fermenting, not a rotten one), or if there are strings of cloudy muck in the liquid, the batch has spoiled and should be discarded. Note that mold is not necessarily a reason to abandon your ferment (see below).

Two things that can help prevent both a non-starting ferment and a spoiled one are adjusting the amount of salt according to the ambient temperature, and/or including a live culture starter from whey (such as that from strained yogurt; see the Dairy chapter).

There’s scum on top of your ferments

Assuming that all the signs (non-moldy, frothy bubbling and a clean, lightly sour smell) of healthy fermentation have occurred or are occurring, any scum that forms on top of ferments is harmless and can simply skimmed away. You can also simply remove the top layer of the fermented food: What is underneath is usually in perfect condition.

Canning Woes

Your jars don’t seal

There are four main reasons why a canning jar may fail to seal after boiling water bath or pressure canning.

The first is overfilling the jars. If you left less than the amount of head space (the space between the surface of the food and the rim of the jar) specified in the recipe, a good vacuum seal won’t form. If the recipe instructions don’t specify an amount of head space, then between ½ and ¾ inch is a good all-purpose distance to use. This also happens to be the distance between the rim of the jar and the ridges just below its screwband section, which makes it easy to measure.

The next reason why a jar may not seal is that there was some food or liquid on the rim of the jar. This can prevent the adhesive ring on the underside of the lid from fastening on. To prevent this from happening, always wipe the rims of the jars clean after you have filled them with the food you are canning. Use a moist, clean cloth or paper towel.

The third reason a jar may fail to seal is that the canning lid is defective. This can happen with new lids—it is rare, but it does happen. More likely is that you reused a canning lid. With two-piece lids you can reuse the screw-on ring, but not the central disk. Single-piece lids are not supposed to be reused at all. The reason is that previous use may have worn out the adhesive ring, or there may be some barely noticeable dent or bend that could prevent a seal.

The last reason why a jar may not seal is that there is a tiny chip or crack in its rim. Always carefully examine each jar before using it, and recycle any that have chips or cracks. This is especially true of jars that you have reused many times or that you purchased secondhand from a garage sale or thrift shop.

A jar breaks in processing

You open the canner to find broken glass and food floating in the hot water. Or everything looks fine until you reach in with your jar lifter to lift one out and the entire bottom drops off the jar. Not fun. 

Here are the three possible explanations of what went wrong, and how to prevent a repeat experience:

The most likely culprit is a hairline crack in the jar that you didn’t notice when you got it out for your canning project. As I mentioned in the unsealed jars notes above, always inspect jars to make sure they are free from cracks or chips before using them.

Another possibility is too sudden of a temperature shift. Although canning jars are designed to withstand high heat, if they are cold when you pour in boiling-hot food, or the jar and the food in it are hot but water in the canner is cold, or any other sudden jolt occurs from hot to cold (or vice versa), the jar may crack. Often this will be a hard-to-spot hairline crack that you won’t notice until the jar breaks during processing. Always fill empty jars with hot water to heat them, then pour the water out before adding hot food. Make sure the water in the canner is equally hot before adding the jars of hot food.

One last reason why jars could break during boiling water bath or pressure canning is that you didn’t put a rack or towel in the bottom of the canner before adding the jars. The glass jars bounce around a bit during processing, so you need to place a buffer between their bottoms and both the metal bottom of the canner and the heat source directly under it. If you follow the canning instructions given in this book, this won’t be an issue.

Fruit floats and discolors

The peaches floated up out of their canning syrup, or the tomatoes separated from their juices and are now suspended above an unappealing watery layer, or the picked green beans rose out of their brine. None of these jars is attractive. Worse yet, the fruit pieces or vegetables that rose above their canning liquid into the head space below the lid may turn brown. Yuck.

Now, if the food was processed according to instructions and the jars successfully sealed, the food inside is safe to eat. Still, it isn’t very enticing when the color has gone off or the solids separated from the liquids (it’s true that we eat first with our eyes!). To prevent these problems, the first thing you want to do is keep the fruits or vegetables from floating up out of the canning liquid. Once out of the canning liquid, many ingredients have a tendency to brown.

The first solution works when you are dealing with relatively long pieces of food that you are going to stack vertically in the jars, such as green beans, carrot spears, or cucumbers. Be sure to pack the food in tightly. Really tightly: Keep shoving the pieces in until you can’t find room for even one more. This is especially important for recipes such as pickles that start out with raw vegetables in the jars: They will shrink a bit during the canning process.

That leads directly to the second solution for float and discoloration, which is not to raw pack ingredients for canning. For fruit, tomatoes, and vegetables that do not need to be crisp (in other words, those that will be pressure canned in a plain salt brine or chopped and cooked into a soft-textured recipe such as chutney), I recommend hot packing. Hot packing means that you cook the food a little bit before transferring it to the jars. This single step goes a long way toward preventing float and discoloration.

Even so, you may end up with a little bit of separation in the jars between the solid food on top and the liquid on the bottom. Once the jars are completely cooled and the lids firmly sealed, you can redistribute the contents of the jars by lightly shaking them. But it is really important that you do this only after the ingredients are entirely cooled and sealed, or you could actually prevent or undo a safe seal.

Pickling Predicaments

“Help! My garlic turned blue”

Pickled garlic will sometimes turn blue. This is the result of an enzymatic reaction that occurs occasionally when the sulfur compounds in garlic are exposed to oxygen and then to an acidic environment such as a vinegar-based pickle brine. The bright blue color may seem alarming, but actually it is harmless and the pickles—including the blue garlic—are still perfectly safe to eat.

Mushy pickles

Crunch defines pickles just as much as their tangy taste, so it’s no fun when your pickles turn out mushy. While there is no way to restore a firm texture to a pickle that has already gone soft, there are ways to slant the odds of achieving the crisp consistency you’re after in your favor.

The single most important thing is the quality of the ingredients you start out with. A limp cucumber cannot, ever, turn into a crunchy pickle. So always start out with firm, unblemished vegetables or fruit for the best pickles. This usually means younger and smaller vegetables. If you have less-than-perfect produce to work with, opt for a finely chopped or pureed recipe such as a chutney, relish, or ketchup rather than pickling large pieces of food.

Jam and Jelly Troubles

Jelly doesn’t gel or jam isn’t thick enough

Jelly and jam need the magic triad of sugar, pectin, and acid in order to achieve the gelled-but-spreadable consistency we expect from them. If any one of these elements is insufficient, you could still eventually arrive at an acceptable texture by boiling the ingredients until enough moisture evaporates out, but the long cooking time would eliminate much of the fruit flavor and color from the final product.

If your jelly or jam didn’t gel despite reaching the sheet test or wrinkle test stage (see the Sweet Preserves chapter of Preserving Everything), there are a few possible reasons. One is that you decided to skimp on sugar and skimped a little too much. Another possibility is that there wasn’t sufficient pectin: Low-pectin fruit needs a boost in order to achieve a gel (the Sweet Preserves chapter lists which fruits are high or low pectin). Still another possibility is that there wasn’t sufficient acid, either from the main-ingredient fruit or from added lemon juice. And yet another possibility is that you didn’t bring the mixture to a full, rolling boil and let it boil over high heat for at least a minute.

One solution is to reboil the food for 5 to 10 minutes. Another is to add an additional cup of sugar plus ½ cup of homemade pectin and reboil for an additional 2 to 5 minutes.

Yet another solution is to fix the runny jam or jelly by adding commercial pectin and a few other ingredients. To do this, first measure the preserves that need fixing. Then, for each quart of jam or jelly, add either 2 tablespoons commercial liquid pectin, 3/4 cup sugar, and 2 tablespoons bottled lemon juice; or 4 teaspoons commercial powdered pectin, 1/4 cup sugar, 2 tablespoons bottled lemon juice, and 1/4 cup water. Either way, stir the additional ingredients into the preserve you want to thicken, bring the mixture to a rolling boil, and boil it for 1 minute before ladling into freshly sterilized canning jars, covering with new canning lids, and processing in a boiling water bath (see the Boiling Water Bath Canning chapter of Preserving Everything) for 5 minutes.

Jelly that is too thin can always be used as syrup. Just sayin’.

Jam or jelly is too thick

You overboiled, and once the result cooled in the sealed jars it was closer to a thick block of fruit leather or a sticky, gooey syrup than the spreadable preserve you were after. Although there’s no way to transform what you’ve got into that originally intended product, there are a couple of ways to still salvage a usable, even tasty result.

In many cultures, especially those in many European countries, there is something called a fruit “cheese.” Basically, this is just a fruit jam or jelly or butter that has been cooked until it is relatively solid and sliceable once cooled. The quince paste in the Dehydrating chapter is similar to this sort of preserve. Try setting a jar of your overcooked preserve in a bowl of piping-hot water for a few minutes. If you can then slide it out in one cylindrical piece (maybe with a little help from a table knife swiped around the sides), then just call it fruit cheese and serve it with crackers and the other kind of cheese.

Or, once you’ve set the jars in hot water long enough to soften the contents and pry them out, recook the preserve with a little water. It will never be jam or jelly, but you can turn it into usable syrup this way.

Dehydrated Food Dilemmas

Moisture condenses on the insides of containers of dehydrated food, or you see the greenish white fuzz of mold on some of the food

If the containers were completely dry when the dehydrated food went in, and if they were tightly sealed, then the only possible explanation is that the food wasn’t dried well enough. If you catch this within a day or two of putting the not-quite-dried food into the containers, and if there are no signs of mold, you can fix the problem by simply returning the food to the dehydrator or oven, using the temperature originally specified for drying that type of food. How much additional drying time the food will need depends on how under-dehydrated it was in the first place. Make sure that you can see no beads of moisture form along the break line when you snap a piece of the food in half.

If the food was fully dehydrated, maybe even crispy-dry, and you see condensation on the insides of the container, then moisture got in from outside. Probably the container wasn’t tightly enough sealed.

Here are two suggestions for avoiding moisture problems with dehydrated foods:

Take the time for the conditioning step with dried fruits and vegetables. This is the step in which you fill a jar only two-thirds full and shake it daily for a week before finally transferring the food to fully filled containers (see individual ingredient instructions for specifics). This not only redistributes any residual moisture in the food, but also gives you a chance to spot early on whether the food needs additional drying time.

Store dehydrated food, at least during that initial conditioning period, in transparent containers. Although I am a fan of stainless-steel food storage containers, with recently dehydrated food it is essential to spot even the scantest fog of moisture before mold becomes an issue. Since you can’t see that through an opaque container, and clear, solid plastic presents its own problems (BPA health risks, for starters), glass is the way to go.

“My celery looks like straw”: Why dried food loses color

If your bright green celery turned hay-beige once dehydrated, and your once orange carrots turned a weird sort of pale clay color, there are two things that could have gone wrong.

The first is that you didn’t properly blanch your food. Although some foods can be dehydrated without first being blanched, many will lose their color in storage unless you take the time for that “extra” step.

The second thing is that you stored your dried vegetables or fruits in a place where they were exposed to a lot of light or heat, like next to your radiator or in a sunny window.

So . . . do pay attention to those blanch?before?drying instructions, and don’t store dried foods near direct light or heat.

“Can I Still Eat This?”
Freezer, Fridge, and Cold Storage Spoilage

Freezer burn

Freezer burn occurs when moisture in the food evaporates into the freezer or into the air surrounding the food in a freezer container. It appears as a frost on the surface of the food, and causes whitish discolorations on the food. Although it isn’t dangerous, freezer burn adversely affects the taste and texture of food, and can give it off odors.

The two main causes of freezer burn are storing food in the freezer too long and not packaging it well enough. There’s really nothing you can do about the first problem except label and date everything that you put in to the freezer, and use up the oldest items first. To package food well for freezing, you need to minimize its exposure to air. That includes air inside sealed freezer bags and containers. Vacuum sealing will prevent freezer burn for the longest amount of time, but simply pressing the air out of bags and wrapping meats well will help significantly.

Rotting in cold storage (including your refrigerator)

Remember that cold storage delays spoilage, sometimes for months, but cannot actually eliminate it. Always remove any food showing signs of rotting so that it doesn’t speed the spoilage of the rest of the food. Aside from simply having been in storage for too long, or being exposed to an already rotting fruit or vegetable, the most likely reason that food spoiled faster than it should have in cold storage is that it was improperly stored to begin with. See the Cold Storage chapter from Preserving Everything for specifics on how to correctly store food in your refrigerator or root cellar.

Read more from Preserving Everything:

Reprinted with permission from Preserving Everything by Leda Meredith and published by The Countryman Press, 2014. Buy this book from our store: Preserving Everything.