Milk Preservation Techniques And Equipment
Milk is a major ingredient in most recipes. It adds flavor and loads of nutrients. But how do you preserve your milk to guarantee its presence in your recipes? Well, milk preservation dates back decades ago when windmills were in use before the arrival of refrigeration. The secret behind milk preservation is low temperatures as this inhibits the activity of bacteria that turn the milk bad.
Today, we can proudly say that you can preserve every droplet of milk harvested from you high yield goats or cows. There is actually no reason why you should be having some milk going to waste. Explore to find out the skills and techniques, as well as the milk storage and preservation equipment that can help you make the best of your milk production. Do not feel left out if you only need to preserve milk in your home but you aren’t a producer, this will be very helpful for you too.
Has it ever occurred to you that you can salt your milk? Probably not but to many people’s surprise this is one of the renowned milk preservation techniques. You may not necessarily need to salt your milk but what about milk products? Salting is a technique that is popularly used to preserve cheese and butter. Salting not only preserves milk products but also adds flavor and weight while reducing water content. Water reduction is very vital as it slows the ripening process by inhibiting fermentation. This guarantees you of higher quality cheese that will have a longer shelf life. You can learn more about cheese and the cheese making process in this post on the best cheese cloth reviewed.
Just like other foods, milk can also be dehydrated. This basically means turning the milk into powder form. From its nature, milk is in liquid form and converting it into powder is not an easy task. Milk in percentage contains 3.5%-4.5% fats, 8%-9% non fat solids. This means that typically only 12.5% is solid and 87.5% fluid.
The principle behind milk dehydration is the use of dry, hot and moving air to remove the water or solvent content in the milk. With hot air, you are guaranteed that the moisture will be absorbed with the heat making the drying process even faster. If the air is stagnant, it tends to retain the water vapor collected and this makes the dehydration process less efficient thus the need to keep it moving. There are different drying methods that may be used which include; spray drying, bed dryers, supercritical drying, freeze drying, dielectric drying, Roller/drum during and Shelf drying. Let’s discuss some of the commonly used methods.
Milk is a closely monitored product and the standards are quite high. This being the case, selecting the right dehydration method becomes quite important as it determines the quality of products to be produced. spray drying has proven to be one of the most reliable techniques explaining why it is widely used in industrial processes.
Basically, spray drying starts where the milk is atomized into a spray of droplets. The droplets then go into the drying chamber where it comes into contact with hot air. Here, the temperatures are controlled to allow the formation of dry particles. As the powder dries, it is discharged from the chamber. Cyclones or bag filters (sometimes a combination of the two) are used to recover the powder from exhaust gases. Some people have also invented a way of using wet scrubbers.
Just like the name suggests, freeze drying/ lyophilisation involves freezing of the solvent before the drying process can begin. the frozen solvent is then dried and sublimed to convert it into gas form. This is done below the solvent’s melting point which retains the biological properties of proteins, bio activity compounds and vitamins.
Freeze drying can be done at atmospheric pressure in the presence of dry air. Alternatively, a vacuum pump may be used to remove the vapor produced during sublimation and converting it into ice. Once that is done, the vacuum can be broken by the use of inert gases such as nitrogen before sealing and packaging of the milk product.
Roller drying is a common liquid drying method where the fluid is dried at low temperatures over high capacity, over rotating steam heated drums. At the end of the process, sheets of drum dried products which are then milled into powder or flake are produced. Normally, the roller drier will be 1 to 6 meters long depending on the capacity. Its performance is pegged on its surface temperature, film thickness, dry matter content and the roller speed.
One of the reasons behind the roller’s popularity is he ability to retain most of the original nutritional value, color and flavors. The high temperatures however may denature milk proteins and result in brown discoloration.
Milk condensing basically involves boiling the milk to evaporate the water content and adding sugar. The end product is sweetened condensed milk that is mostly used in baking. Unsweetened condensed milk, also known as double concentrated milk, is also in high demand and we shall discuss how you can preserve your milk using the condensing method whether sweetened or not.
Unsweetened Evaporated Milk
The Large scale manufacture of evaporated milk starts with the pumping of heat treated milk into an evaporator to be concentrated. This is then followed by the homogenization and cooling of the concentrate. At this stage, checks on the coagulation stability are done and stabilizing salts (trisodium or disodium) are added.
When condensing milk at home, the process may be a little different and here are the steps you can follow.
- Have a heavy bottomed pan and pour two of the four cups of milk.
- Use a wooden spoon and stick it into the milk holding it straight to mark the milk level.
- Pour the other two cups into the pan.
- Heat the milk to bring it to a simmer. Keep stirring to ensure that it does not singe.
- Remove the skin forming as milk reduces.
- Regularly measure the milk level using the wooden spoon. When the level hits the mark you made earlier, your milk will have reduced by approximately 60% and that’s good enough.
- Leave the milk to cool before canning.
Note: If you need to reconstitute the evaporated milk, you can add an equal amount of water to it.
Sweetened Evaporated Milk
Sweetened condensed milk is very popular in the kitchen as it is used in numerous recipes. The major advantage of having such milk is that you do not necessarily need to store sugar that attracts ants and rodents in the house yet you won’t have challenges sweetening your foods. It’s also ready to eat and contains vital fats and calcium.
The process of making sweetened condensed milk varies slightly to that of making unsweetened evaporated milk. You will need to have 1 1/2 cups of whole milk, 1/2 cup of sugar, 3 tablespoon butter and 1 teaspoon vanilla. Here is how to go about it.
- Have a heavy bottomed pan and place one cup of milk.
- Use your wooden spoon or spatula to mark the milk level in the pan.
- Add your sugar into the milk.
- Heat and bring the mixture to a slow simmer. Stirring regularly will prevent burning.
- Observe the liquid level and remove from heat when it reaches the level marked earlier.
- Add the butter and vanilla and whisk.
- Let the mixture cool and preserve in the desired way.
Note: You can use honey instead of sugar as it is a healthier option.
Just like other farm products milk can also be canned. The secret behind milk canning is air tight seals and hygiene. If you have decided that you will be using milk canning to preserve your milk, hygiene should be paramount and should start right from the milking process. Use extremely clean milking equipment and ensure that the cow’s udder and teats and clean and disinfected. Pasteurize the milk and store it in clean covered bowls to ensure that nothing contaminates it.
Wash jars and containers that you intend to use in hot soapy water to remove all the dirt and rinse thoroughly. Keeping these containers submerged in hot water until use helps keep off germs that may contaminate your milk.
When filling the jars with milk, leave half an inch for headroom. Carefully clean the jar rims and place the sterilized hot rings and rims on them. Place them in the pressure canner and ensure that the recommended amount of water is filled. Place your canner on the stove, preferably the hottest part o the stove. Set the pressure at 10 or less and cook pints for twenty minutes or quarts for twenty five minutes. Ensure that a constant pressure of 10 is maintained else you will need to start all over again.
The reason behind using pressure canner is the susceptibility to botulism normally found in the soil. Pressure canning ensures safe temperatures thus killing any bacteria. That way, your milk will easily hit two or more years without going bad.
Milk is a common ingredient in most recipes but is not common place. You will thus need to make the best of the available milk and preserving it while in plenty. The methods discussed in this post will help you preserve your milk, in milk form, without necessarily having to refrigerate it. They will come in handy in survival situations and the dairy cow’s drying period. We will be discussing other forms of milk preservation and milk products in a different post. Go ahead preserve your milk for the tough times ahead.