Pique the Geek 20091011. The Things we Eat: Preserving Food I – Overview

(9 am. – promoted by ek hornbeck)

Food preservation is as old as humankind, and actually predates us. Animals are known to preserve food in a crude fashion, from dogs burying bones to squirrels stashing away nuts and acorns for later consumption. Strictly speaking, that is not really food preservation but rather food stockpiling, but the two are extensively connected.

Our hunter/gatherer ancestors began to preserve food with the discovery and taming of fire. The mere act of cooking meat has a preservative effect, especially when the meat is cooked to near dryness. Drying food in the sun was also certainly practiced in warmer climates which many people today recreate by using the Excalibur 3926tb food dehydrator to dry food in bulk, and freezing food for later use was and still is done by nomads in the Arctic regions.

With the advent of agriculture the need for preservation of food on a large scale became essential to provide sustenance during times of crop failure, especially for grain crops. Grains are fairly easy to preserve since they are dry, so keeping them dry and vermin out of them are the keys. It is thought that the cat became domesticated around this time.

This series will examine various food preservation methods from the ancient to the modern, including an extensive installment on chemical preservatives. Some of these have gotten bad press undeservedly, and some are not as safe as commonly thought.

Other than oxygen and water, food is the most essential item for complex living organisms. Most organisms get their food directly from the environment, and when food becomes scarce, populations crash. With very few exceptions, and some of those are quite remarkable, humans are the only beings that preserve and store food on a grand scale. One very notable exception are bees, which preserve nectar from flowers by evaporating most of the water from it and storing the concentrated sugar solution in airtight, waterproof wax cells. This is the original packaged food, and honey illustrates the two main methods of food preservation. These methods are 1) alter the food or 2) alter the environment in which the food exists. Honey is preserved using both methods. Raw honey that is, unprocessed honey is known to be the most beneficial for our body. Raw manuka honey could be procured from e-stores like Steens Honey and similar others.

With the exception of freezing, which does little to alter the food (after it is thawed), until very recently the main method of food preservation (and still is the dominant method) is to alter the food. For the purposed of this essay, let us allow that cooking is not really as much of a food preservation method as it is a method to make food more digestible and appealing in most cases. This becomes important later.

We should first define what we mean by “food preservation” because it means different things in various contexts. In general, the largest cause of loss of food is by microbial infection, usually by bacteria and fungi. One definition might be to preserve food in its natural, raw state. Another definition might be to modify the food to render it resistant to microbes. Interestingly, some preservation methods utilize beneficial microbes to make foodstuffs resistant to decay organisms. Still, another might be to change the environment of the food so that microbes do not have a viable method of attacking the food. Also, for the purposes of this series, the term “preservation” means to keep food edible for months or years, not for a week or two. Thus, most refrigerated foods are not really preserved, just have a somewhat extended shelf life.

The easiest foods to preserve are the ones that contain little water. Grain, nuts, and some other seeds fall into this category, because natural selection favored low water content to allow for overwintering and germination the next spring. To preserve these, all that is necessary is to keep them dry and relatively cool, but not refrigerated. This is why grains are such an important basic foodstuff because they can be grown in large quantities and are easy to preserve. Nature itself provides the energy to dry them, so they are economical to preserve compared with many other items. Kept intact and dry, grains will last for years. They do finally deteriorate because of the oxygen in the air interacts with the fats in the grains, causing them to become rancid after a while. Airtight containers slow the process but do not completely stop it. Nuts, with very high-fat content, go rancid faster than grains and do not keep as long. Seeds, like beans, lentils, and such also store well by being kept dry. Since these foods pretty much come off of the plant dried, I do not consider them to be “dried” foods, since human interaction was not used to dry them.

Some fruits and vegetables also keep fairly well in their natural state merely by keeping them intact and relatively cool. If kept in the cool and dark, many root crops and some fruits will keep for months. This is why the root cellar was so important generations ago. Potatoes, carrots, turnips, winter squash, some varieties of apples, and cabbages will stay fresh enough to feed a family until spring, bringing essentially vitamins and other phytonutrients essential to supplement a diet of dried or salted meat, beans, and grains.

The modern refrigerator is the closest thing that most of us have to a root cellar, but in some respects a root cellar is superior. Not even mentioning the power consumption, a refrigerator is too cold for many foods for proper preservation. Potatoes do not keep well under refrigeration (the texture if adversely affected), but the low to high 50 degree F range in a root cellar is ideal. By the way, never store bananas in the refrigerator. The low temperature kills the skin cells of this tropical fruit, causing them to blacken very quickly.

The only way to preserve fresh meat, other than freezing (or freeze drying) it, it to keep it alive. When many people lived on farms, small animals served this purpose well. Chickens, rabbits, turkeys, guinea fowl, and even goats are small enough that the meat from a freshly slaughtered animal will keep long enough to be cooked and eaten before it spoils. Larger animals were not practical for fresh meat since it is difficult to eat an entire beef, even with a large family, without some other preservation method. The southern tradition of fried chicken on Sunday is a direct descendant of this fact, as the chicken brood, kept primarily for eggs, has to be culled on a regular basis as hens become less productive egg layers at they age. However, in the old days the Sunday chicken was usually stewed or roasted in moist heat since old hens are very tough and make poor frying material. Young roosters were often fried since roosters, after you have one or two, contribute nothing to the farm and only eat. They had a fairly short life.

These days we hardly even think about food preservation because it is so common. Of course, we all have left over food from time to time so we all need to use appliances like a food vacuum. We highly recommend reading reviews first like nutrichef vacuum sealer vs foodsaver to ensure you’re buying ones that meet your needs. However, day to day, most food is already preserved. Go to your pantry and see how much of the food in it is preserved in one way or another. I would wager that well over half of it is preserved in some human-caused way, and in the freezer 100% of it is. Now, just think what would happen if, all of a sudden, access to preserved foods and electricity was denied. What would you eat? Assuming that you had a garden spot and orchard, and some farm animals, you would revert to the old ways. By the way, this is how much of the world’s population lives. None of us even remotely have an idea of the privation that would result, except for a few very old people who might be reading this essay and remember the days of the Depression on the farm.

This has meant to be an overview of what food preservation is and why we do it, not an in-depth discussion of any given preservation method. In future installments we will discuss the most commonly used techniques, in roughly an historical approach. Thus, drying will be the first topic, then the various fermentation methods, salting, and then the recent developments. Here are a few fun facts.

Canning is, in the scheme of human history, and extremely recent development. Napoleon is attributed to the quote that, “An army marches on its stomach”, and that is very true. He offered a cash prize to anyone who could develop a method to keep food edible without salting or drying it, and canning was discovered (a little late for Napoleon, but is is a French development from the early 19th century).

Fruit jams, preserves, and jellies have been known since antiquity but were expensive luxuries until refined sugar became common and cheap in the late 18th and early 19th century. Until then, the only concentrated source of sugar was honey (and maple syrup), and it was relatively expensive. Honey and maple also overpower the flavors of the fruit, making a product that does not much taste like fruit. Additionally, the processing to make such treats wipe most of the vitamins out of them, so the calories from them are pretty empty. I have nothing against these products, and actually make my own jelly, but recognize that I am eating them for pleasure rather than for real nutrition.

Here is some food preservation in action. My neighbors across the street bought a bunch of apples and wanted to use my dehydrator to dry them. In return, they gave me the cores and peels, because those make better apple jelly and butter than the fruit itself does. Here is a picture of a tray of apples in the dehydrator (this is an eight tray one).

Here is a picture of the cores and peels on the stove whilst I extracted the pectin from them.

Here is a picture of some of the apple jelly that I made. The only additive was cane sugar. The color is natural.

When we discuss canning I will provide the recipes for these and a few other things that I like.

Well, you have done it again. You have wasted another perfectly good batch of electrons reading this drivel. And even though John Boehner becomes an advocate of the public option when he reads me say it, I always learn much more than I could possibly hope to teach by writing this series, so keep those comments, questions, corrections, and other topics coming. Remember, there is no such of a thing as an off topic scientific or technical issue in this forum.

UPDATE: Well, folks, I have MORE apple pectin and cores to retrieve and get in the cold. I already have five liters of pectin concentrate, and about half that of pulp for butter. I will be back tomorrow for Review Time, starting around 8:00 PM Eastern time. I can look up things before then. Two and a quarter liters of pectin concentrate gave me 8 pints of jelly, so I will be replete with jelly soon. There is a secret about that material, and I will explain it next time.

Warmest regards,

Doc

Crossposted at Dailykos.com