Preserving Food

By : | 1 Comment | On : November 3, 2011 | Category : Editorial

Preserving Food - Canned Goods

Preserving food is an incredibly powerful process that far too few people take advantage of. With this article I would like to walk you through some of the basic methods, and point you in the right direction to get started. I’ll touch on the usefulness of food preservation, and explain each of the processes a little bit. Hopefully it will pique your interest, and you can join Jen and I, and legions of other food preservers out there.

Why does food go bad?

Clostridium botulinum

Clostridium botulinum - This guy will kill you!

To begin, why does food go bad exactly? Why are we preserving food in the first place? If food didn’t go bad, we’d never have to worry about sour milk, vinegar-smelling apple cider, or science fair projects in the back of our fridges. There are a two big reasons, called bacteria, and fungi. They’re everywhere, and they’re in almost everything we eat in tiny numbers.

The bacteria break down food just like you and I do. The problem is when they do it, they produce, um, “byproducts”  (we do that too I guess). The thing is, some of these byproducts can hurt us, for instance e.coli makes a really nasty toxin. So does botulism. They can also make our food really unpaletable. Oh, they also reproduce when they eat food, so the one or two cells that wouldn’t hurt us suddenly turn into 10 million, and their big happy family gives you an expensive and potentially fatal trip to the hospital.

A Moldy Sandwich

A Moldy Sandwich - yummy!

Fungi are critters kind of like bacteria. They include molds and yeasts. They eat sugar, and when they do they tend to create more fungi. Again their eating food produces byproducts. In the case of yeast you end up with some alcohol, and some carbon dioxide. In the case of some molds, you end up with penecillin. Other times you end up with molds that kill you infesting your food.

Preserving food lets you keep these guys at bay. And its darn useful!

So why is “preserving food” useful?

Well, basically preserving food lets you take almost any type of food stuff, and process it in such a way that it can be kept for an extended period of time. You’re probably saying, “Well, duh.” But just think about it for a second, and let it sink in, because its a powerful thing. If you capitalize on seasonal food sales, or cycling deals at the grocery store, a little knowledge on how to preserve food lets you stock up when prices are low. For instance, suppose you see a sale on peaches for 50 cents a pound (a recent sale at Bottom Dollar food stores). 10 dollars would get you 20 pounds of peaches. With a little preparation, you could have a TON of long-lasting snacks out of that batch of peaches – easily enough to last you for months. You could puree some and dehydrate them into a fruit leather. You could puree it and turn it into a fruit ice by freezing it. You could slice them and can them, and they’ll keep for up to a year. Every time you eat them, you’re saving yourself from having to buy new snacks. You’re also eating healthier, since no preservatives had to be added. It’s all natural food.

You can do this every time you see a sale. This is why people used to keep pantries – you buy things when they’re cheap or when you have excess, and you keep it for the long term. It saves you money.

There are a wide range of methods to do this, from freezing and dehydrating, to salting, to canning. You’re probably most familiar with freezing, so lets start there.

Freezing Food

Frozen Food

What frozen peas or corn may look like

I’m going to geek out for a second and use some technical terms. Sorry!

Freezing foods works on the premise that most bacteria, fungi, and other nasty things that spoil food slow down as temperatures drop. Basically, you know how a person’s heart rate drops when they get hypothermia? Its the same thing for the bacteria and other nasties that can start to get in your food. Freezing works well, but not for a super long term. Eventually frozen foods will start to get freezer burnt – especially if the temperature isn’t kept consistent. However, this is the most easily accessible way to preserve food. It also can be used for many foods which can’t be preserved in other ways. Jen and I tend to make far more food than we need, with the intention of freezing half of it for future meals. Soup is really great for this.

Dehydrating Food

Dehydrated Food

Some delicious dehydrated raisins

Dehydrating is one of the oldest and simplest methods of preserving food. Basically so much water is removed from the food that it inhibits bacteria from growing and eating our food, and producing nasty toxins. In old days, you could hang food up to dry, however it still wouldn’t prevent molds from getting a hold on them.

These days, you can use a specialized food dehydrator to remove all of the moisture in a safe environment, which prevents any molds from making their way in. This is how fruit leathers are made.

Salting Food

Salting food is extremely old method for preserving food. Basically brines were used because salt sucks the moisture out of bacteria. If you have a brine with more than 20% salt – guess what? All of your bacteria are dead. The downside? Your delicious lox bagel sandwich is giving you high blood pressure. Life is always a trade off, isn’t it?

This method is still used some places today, like with lox (as mentioned above), bacon, and salted cod.

Vacuum Sealing Food

Vacuum sealing food removes all air from the environment around the food. With no air, bacteria can’t breathe. They’re rugged guys, so eventually they’ll still be able to spoil the food, but not before you’re done eating it.

Canning Food

A Pressure Canner

A pressure canner - yes, they really look this awesome.

This is the one I really love – canning food. There are two major ways to can food, and they work in slightly different ways. Hot water boiling is used for foods which are already acidic, since the acidity prevents a large amount of bacteria by its very nature of being acidic. Pressure canning is used for low acid foods, since they can allow a far larger variety of bacteria to grow.

Hot water boiling

In hot water boiling you submerge a glass canning jar into a vat of boiling water. This boiling water kills bacteria and mold with heat. it also causes the liquid inside the canning jar to boil, forcing it to steam out from under the special 2 piece lid. As it cools, the vacuum created by the escaping steam sucks the lid on to the jar, creating a vacuum seal.

Pressure canning

Pressure canning utilizes a special piece of equipment called a pressure canner. The device creates an airtight seal around the jars, and builds up steam pressure. This pressure allows the temperature inside of the canner to reach temperatures far higher than 240 degrees. These high temperatures and pressures kill bacteria using a similar process to what is used in hospitals (except there they call it an autoclave, and they also use UV light). Again, the liquid inside the container boils, causing steam to leak out of the two part lid. This creates a vacuum, sucking the lid on.

You’ll notice that most canned goods say that if you see the lid is popped up, not to eat it. Keeping these two methods in mind, you can see why. If the lid is popped, that means that it wasn’t processed right, and there’s no vacuum seal. No vacuum seal means a good chance of contamination.

Now, none of these methods for preserving food has to be done by itself – in fact, you’ve probably heard of freeze drying. Other examples combine salting with dehydration – like in the example of beef jerky. But in the end, they all give you the ability to save food for long periods of time.

I hope you guys found the article informative – if you did, there are going to be some recipes coming up you might enjoy!