Evaporated milk begins its life as fresh, regular cow milk. The problem with fresh, regular cow milk is that, once removed from the cow, it doesn't stay fresh very long. There are several solutions to this problem. Developing nations with cows wisely leave the milk in the cow† until an immediate need presents itself. First world nations tend to discourage raising livestock within city limits and instead rely on refrigeration, although this is a temporary solution.
Milk is a highly nutritious food, and organisms both macro- and microbiological appreciate this fact. When the milk is in the cow, the cow's immune system keeps it fresh by killing the microorganisms. When the milk is in the refrigerator, the cold environment slows the metabolism of the microorganisms, keeping it fresh longer. A third option would be to remove the microorganisms from the milk, so they're not there to spoil it in the first place. While we're at it, let's remove most of the water from it to make it more compact. Because we can.
Milk is processed into evaporated milk by careful heating in a low pressure environment. This evaporates 60% of the water out of the milk, reducing it to half its original volume. Precision standardization of the end product is critical: If whole milk was used, the evaporated milk contains no less than 25% milk solids and 7.5% milk fat. Skim milk is reduced to no less than 17% milk solids, and not more than 0.3% milk fat. Failure to meet these requirements must result in some retribution too horrible to print, since none of my sources dared touch on the subject.
Some nutritional information:
- Moisture 75.0%
- Lactose 9.5%
- Fat 7.5%
- Proteins 6.5%
- Ash 1.5%
Stabilizing salts such as sodium citrate, disodium phosphate, or calcium chloride may be added, and sodium ascorbate can be used as a preservative. Often vitamins A, C, or D are added. The concentrated milk, in some ways similar to cream, is then packaged in cans and heat-treated in an autoclave at 110°C (230°F) to sterilize it. As a result of all this heating, evaporated milk takes on a light brown color and slightly cooked flavor (due to the Maillard reaction). After sterilization, evaporated milk has a long shelf life — up to two years at 0-15°C (32-60°F). However, once the can is opened, any leftover must be refrigerated. Swollen cans are an indication that the contents have fermented or spoiled. Its long shelf life makes evaporated milk an important source of nutrition in the third world. Although not palatable straight from the can, it can be diluted with an equal amount of water to approximate milk.
In the interest of journalistic integrity, I purchased a can of evaporated milk to test that claim. I think "unpalatable" was indeed the correct term for it straight out of the can. Mixed with water, it certainly didn't look like milk due to the browning from the heat treating, but it tasted better. In my opinion, a bit like soy milk. I should mention that I do not like soy milk. It was drinkable after being chilled in the refrigerator, although I have to say I strongly prefer 2% milk. But then, I'm a middle class white male living in the richest country in the world and have a grocery store just across the street and a refrigerator to keep it in, so my options are somewhat more flexible.
So, back in the first world (where the average person has the computer and communications technology to actually read this article), evaporated milk is mostly used in cooking, often as a substitute for cream. In fact it was once a popular cream substitute for coffee, although now artificial creamer has stolen its limelight in that respect. Cream spoils relatively quickly, even with refrigeration, so evaporated milk has a significant advantage in that respect. Additionally, evaporated milk can withstand high temperatures without curdling. Evaporated milk can be substituted directly for cream, or one half part evaporated milk and one half part water as a substitute for milk.
Condensed milk is somewhat similar to evaporated milk, although it goes through less processing. The large amount of sugar added to condensed milk inhibits microorganism growth enough that sterilization is not required. It is thicker and much sweeter than evaporated milk.
BlueDragon says: Oh, i love it straight from the can, or poured over peaches! Not sure if there's a recipe here for Gypsy tart - you may want to add it - it's kind of an evaporated milk pie! Incredibly sickly, but they still sell it in cake shops in England.
I've found this recipe, written practically word for word, in several places around the internet, so this appears to be public domain.
Gypsy Tart:
Ingredients: (Serves 6)
- (1) 400g (14oz) Tin of Evaporated Milk
- 340g (12oz) Dark Muscovado Sugar
- (1) 10inch Pre-baked shortcrust pastry case
Directions:
- Pre-heat oven to 200°C: 400°F: Gas 6.
- Whisk evaporated milk and sugar together for approximately 10 minutes
- Until light and fluffy and coffee coloured.
- Pour the mix into the pastry case.
- Bake for 10 minutes.
- The surface will appear slightly sticky but will set completely when left to cool.
- Serve cold.
jmpz says: In my house it was used primarily as emergency milk when stores were closed or during hurricanes and in my mother's recipe for flan which calls for one can of condensed milk and one of evaporated milk.
Dawggy says: We used evaporated milk to make "Snow ice cream" when we were kids. It was a great sugar rush: evaporated milk, vanilla flavoring, sugar, and fresh snow.
† momomom says: Amusing but inaccurate.
There's a careful balance to be struck when you try to add some humor to a writeup like this, and I have to admit I flubbed this one pretty badly. I only meant to say that without modern pasteurization, homogenization, and refrigeration, factory farms that milk hundreds of cows and store thousands of gallons of milk for later consumption, as we do in the first world, are not possible.
Sources:
http://www.verybestbaking.com/products/carnation/evap/default.aspx
http://www.cooking.com/advice/adgloss.asp?GlossType=ingr&Item=Evaporated+milk
http://www.adl.ca/evaporatedmilk.html
http://www.milkingredients.ca/DCP/article_e.asp?catid=145&page=212
http://www.sspindia.com/dairy-industry/evaporated-milk-plant.html
http://homecooking.about.com/od/milkproducts/a/cannedmilk_5.htm