10 home food preservation methods from ancient to modern
Bommanahalli, Bengaluru Feb 12, 2017
We have all at some point had too much food that we didn't want to go to waste. When such a situation occurs, we try to save whatever is left of that food, so that it can be consumed later. What we were trying to do is preserve the food.
But why were we trying to preserve the food using different methods?
Food that is left without implementing any preservation methods is prone to rotting and spoiling as microorganisms like yeasts, bacteria, fungi, etc. grow on these foods which leads to the speeding up of the oxidation of the fats causing rancidity. Food preservation prevents that and also includes other processes like stopping the visual deterioration of food. An example of visual deterioration is the browning of sliced apples because of the enzymatic browning reaction.
The best way to preserve food is by implementing more than one type of preservation methods.
We humans have been trying to preserve food for thousands of years. In this article, we will discuss some common ways you can preserve your food at home. These include practices that have been followed since the old-time to recent modern food preservation methods.
Some common methods include Canning, freezing, drying, salting, etc. We shall learn more about each one of them in minor detail.
Canning is an age-old method of food preservation in which the food is pasteurised - a process where the product is heated at a specified temperature for a particular amount of time - and then vacuum sealed in special glass jars.
There are three common methods used for canning the food. These include;
- Water bath canning - In this process, a large pot or kettle is filled with water, and the can is placed inside this water on top of another vessel, so as to not touch the bottom of the kettle or pot in which the water is being boiled in. This arrangement is called a water bath, and helps preserve high acid foods such as fruits, Jams, jellies and other spreads, Tomatoes (with added acid), and Pickles and relishes.
- Steam Canning - This makes use of a special canner that makes use of steam to pasteurise the food. Steam canning is also used to preserve high acid foods.
- Pressure Canning - This canning method makes use of high temperature along with steam that has really high pressure to store the food. It is used to preserve foods with low acid content such as carrot, beans, corn, soups, meats, broths, sauces, etc.
Before canning, you must make sure to have all the materials such as reusable canning jars and rings, one-time use sealing lids, and some practice to learn the necessary and detailed steps. A lot of research must be done before one implements canning as a preservation method.
If canning is done without following the appropriate procedures and safe practises, you become at risk for developing botulism poisoning.
It is common knowledge that cold reduces the speed at which food could rot. In this process, the food is kept cool in an environment with low temperature. Basically, freezing involves removing the heat from whole foods and bringing it a little below the freezing point of food. Although frozen foods last for long, with time the quality might deter a little.
Freezing is a good preservation method as water is frozen, which means microorganisms that could cause decay cannot flourish at such low temperatures. Therefore, the effect of the decreased temperatures, reduced activity in the water as well as the pretreatment of the food by blanching ensures a longer shelf life.
There are different types of freezing systems involved based on the type of food product. Factors such as type of product, cleanability of the food, hygienic design, reliable and economical operation as well as the quality of the product that is determined to determine the type of freezing system implemented.
Freezing can be used on any type of food, including fruits, vegetables, meats, seafood, grains, nuts, dairy, eggs, and prepared foods. Freezing is possible if you choose the right equipment; not the freezer compartment of the refrigerator as its comparatively much warmer.
Drying is a food preservation method in which the product is completely dehydrated, i.e., removed of its moisture content. This is done because moisture plays a hand in helping microbes in the food multiply. When your food is relieved of its moisture content, it inhibits the growth of bacteria, yeasts, and mould; organisms that contribute to food decay.
Drying can be used with foods such as fruits, vegetables, meats, seafood, grains, legumes, and nuts.
Dehydrating the food for preservation is a method of food preservation that has been used for centuries together. Traditionally, water is removed from food by basically evaporating it using techniques like air drying, sun drying, smoking or wind drying. As times progressed, there have been equipment designed to help with the same. In modern times, electric food dehydrators or freeze-drying are being used to dehydrate the food much faster.
To ensure longer-lasting shelf life, one can also add in preservatives, but it isn’t mandatory.
This preserved food is packed using methods such as vacuum sealing, and or adding inert gases.
Fermenting is a food preservation method that involves introducing bacteria or yeast in the food to break down carbohydrates in the food to alcohol or preservative organic acids. Since fermentation is controlled, the bacteria and yeasts that we introduce inhibit the growth of bacteria that could cause food decay. Also based on how the food is fermented, and the type of food being fermented, your food can remain consumable for years.
Fermenting is used to produce products such as wine, sauerkraut, cured sausage, yoghurt, kimchi, kefir, etc. Fermenting processes doesn't necessarily require large machinery unless you’re producing the content in large numbers.
Though the process is easy, one has to pay attention to detail. It is important to sterilise your vessels and equipment or else; the microbes could multiply into harmful organisms and spread diseases.
Pickling is a process in food preservation in which the food is soaked in a solution of salt, acid, or alcohol. It is mainly used in food such as fruits, vegetables, meats, eggs, etc. The process involved anaerobic fermentation in brine or immersion in vinegar. Pickling adds taste and flavour as well as affects the texture of the food. What helps preserve the food is the fact that the solution has a pH of 4.6 or lower, which kills bacteria. When fermentation occurs at room temperature, the food gets the required acidity.
Usually, pickling requires no special equipment. Pickling has to be prepared carefully or stored at room temperature; otherwise, the food can be unsafe. Pickling has to be combined with other methods such as fermenting, canning, or just refrigerating.
The flavour of the end product is determined by the acidity or salinity of the solution, the temperature at which the food was fermented, etc.
Dry salting is a technique used to preserve meat, fish and vegetables. When the food has a high salt concentration inhibits microbial growth, thus ensuring that the food is preserved and doesn’t decay; but it will still have a salty taste. People familiar with food that has been preserved with the salting technique prefer it over canned or frozen food products of the same.
Salting has been around for centuries but was promoted in the 20th century as an alternative for Canning. This was because, during the time of war, people needed to conserve glass, tin and fuel; which were all required for Canning.
Curing is a method of food preservation in which the food is treated with salt to draw out additional moisture. It uses salt, acid or nitrites. Curing is mainly used to preserve fish and meat.
Since the food had increased solute content and low water, the environment becomes unfriendly for the microbes to grow, thus preventing food spoilage.
The approach to curing is made by dehydrating the food using processes such as smoking, spicing, cooking or adding different solutes. The most commonly used solutes include potassium nitrate and sodium nitrite, coupled with salt. These nitrites not only inhibit microbial growth, but recent research has also shown that they prevent botulism, a disease spread due to unhygienic food preservation practices.
In recent times, cured food doesn't use a strong concentration of solute as it will later be combined with other preservation methods like freezing. If the food is supposed to be shelf-stable, then they increase the solute content added to the food, along with a drying process that uses special equipment and requires careful processing.
Some foods that have undergone curing are followed through with other preservation methods such as fermenting, smoking, or sealing.
Smoking is an additional process that is used after curing the food. This process involves exposing the food smouldering or burnt material; usually wood. Smoking improves the flavour and appearance of the food while acting as a drying agent. This process is mainly used on meat and fish.
Smoking is predominantly a technique to add flavour as well as enhance appearance, and not necessarily a food preservation method. But, it is found that smoked meats are less likely to turn rancid or exhibit mould growth.
Sealing is a process of preserving food by covering it in a way that there is no air exchanged. This process doesn’t entirely stop decay but delays it nonetheless. Sealing is used as a complementary process along with other forms of food preservation, such as drying =, freezing or salting.
The most commonly used sealing method is vacuum sealing, which is an easy procedure to follow and requires a relatively small appliance. The best way to preserve the vacuum-sealed food is to deep freeze it.
Food is also sealed using another method called fat sealing. Fat sealing basically involves cooling down animal fat and layering it atop of the food, which must be devoid of moisture. The fat used must be pure and must not contain any bacterial or fungal impurities, and the food must be sterilised, and any existing microbes must be killed by boiling, cooking, etc.
Cellaring is a food preservation method which involves controlling the environment in which the food is kept. Ideally, cellaring requires low temperatures, controlled humidity, as well as very less light. This form of food preservation is used on many foods such as vegetables, grains, and nuts, fermented foods and dry-cured meats.
There are different ways in which food can be cellared, using simple, inexpensive equipment.
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