DAIRY TECHNOLOGY: MILK PROCESSING
Diagram
Sweetened condensed milk and evaporated milk side by side
Sweetened condensed milk
Milk concentrated with sugar added: thick, very sweet, and keeps in the tin without sterilization.
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Evaporated milk
Milk concentrated with no sugar: sterilized in the tin, pourable, and only mildly sweet.
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The core difference
Sugar. One is preserved by sugar, the other is preserved by heat in the sealed tin.
Figure 1: Sweetened condensed milk compared with evaporated milk. Drawn in our own style from A. K. M. Humayun Kober, Milk and Dairy Foods: Nutrition, Processing and Healthy Aging, CRC Press, 2024, Ch. 9, Concentrated Dairy Food: Condensed Milk, p. 218.
Introduction
Sweetened condensed milk and evaporated milk look alike in the tin: both are thick, canned, concentrated milks. One is a sweet ingredient, the other is a plain milk.
The core difference is sugar. Sweetened condensed milk has about 40 to 45 percent added sugar, which is so much that microbes cannot grow in it, so it keeps without sterilization. Evaporated milk has no added sugar, so it must be sterilized in its sealed tin to keep.
Quick comparison
Table 1: Sweetened Condensed Milk compared with Evaporated Milk
| Aspect | Sweetened Condensed Milk | Evaporated Milk |
|---|---|---|
| Added sugar | Yes, about 40 to 45 percent sugar added | No, no sugar added |
| How it keeps | Sugar binds the water, so microbes cannot grow | Sterilized in the sealed tin by heat |
| Water removed | About 60 percent of the water removed | About 60 percent of the water removed |
| Total solids | About 70 percent solids, mostly sugar | About 25 percent solids |
| Texture | Very thick, sticky, pours slowly | Thick but pourable, like light cream |
| Flavour | Very sweet, caramel note | Mildly sweet, cooked milk flavour |
| Colour | Pale yellow to light brown | Pale cream |
| Shelf life unopened | Months to a year at room temperature | Months to a year at room temperature |
| After opening | Keeps weeks in the fridge, sugar protects it | Use within a few days, keep cold |
| Main use | Sweets, fudge, caramel, desserts, coffee | Sauces, soups, baking, tea and coffee as a milk |
Scientific explanation
Definition
Sweetened condensed milk is milk concentrated by evaporation with a large amount of sugar added, giving a thick sweet product that keeps without sterilization.
Evaporated milk is milk concentrated by evaporation with no sugar added, then sterilized in its sealed tin.
Working principle
Sugar preserves by binding water. At 40 to 45 percent sugar, the free water is so low that microbes cannot grow, so the tin needs no sterilization.
Evaporated milk is preserved by heat. The sealed tin is heated until the milk is commercially sterile, and the tin keeps new microbes out. Both products are concentrated to about the same degree, but only one carries sugar.
Apparatus
An evaporator, a vacuum pan that boils the water off at low temperature, for both products.
For evaporated milk, a tin seamer and a retort that sterilizes the sealed tins. For sweetened condensed milk, a mixer for the sugar and a filler.
Measurement procedure
For sweetened condensed milk, evaporate the milk to about 40 percent of its volume, add the sugar, cool it, and fill it into tins or tubes.
For evaporated milk, evaporate the milk the same way, homogenize it, fill it into tins, seal them, and sterilize the sealed tins in a retort.
Factors affecting readings
The sugar level decides the keeping of sweetened condensed milk: too little sugar and microbes can grow.
For evaporated milk, the sterilization time and temperature decide the keeping: too short and spores survive, too long and the milk browns and tastes cooked.
Formulas and calculations
The books give no formula for this pair. The sugar level is a set recipe, not a calculation.
Worked example from measured values: sweetened condensed milk at about 70 percent total solids holds about 40 to 45 percent sugar, so the milk solids are only about 25 to 30 percent. Evaporated milk at about 25 percent total solids holds only milk solids, with no sugar at all.
Industrial applications
- Sweetened condensed milk: fudge, caramel, truffles and sweets where sweetness and body are wanted.
- Sweetened condensed milk: desserts, ice cream and sweetened coffee and tea.
- Evaporated milk: sauces, soups and baking where a rich milk is wanted without sweetness.
- Evaporated milk: tea and coffee as a creamy milk, and emergency milk supply.
- Both: confectionery and baking, with the choice made on whether sugar is wanted.
Advantages and limitations
- Sweetened condensed milk advantage: keeps without sterilization and gives sweetness and body in one ingredient.
- Sweetened condensed milk limitation: very high in sugar, so it cannot be used as a plain milk.
- Evaporated milk advantage: a plain concentrated milk with no added sugar, useful in cooking.
- Evaporated milk limitation: must be sterilized in the tin, and it spoils within days once opened.
FAQ
Can I use evaporated milk instead of sweetened condensed milk?
No, not directly. Evaporated milk has no sugar, so a recipe that needs sweetened condensed milk would come out unsweet and thin. You would need to add sugar and reduce it further.
Can I use sweetened condensed milk in tea?
Yes, it sweetens and creams the tea at once, which is common in many countries, but it is very sweet.
Why does sweetened condensed milk not need sterilization?
Its sugar binds the water so tightly that microbes cannot grow in it. The sugar is the preservative.
Is evaporated milk the same as condensed milk?
The names are often mixed up. Evaporated milk is unsweetened and sterilized; sweetened condensed milk is the sweet one. Check the tin before you cook.
How long does each keep after opening?
Sweetened condensed milk keeps for weeks in the fridge because its sugar protects it. Evaporated milk must be used within a few days, like fresh milk.
References and further reading
- A. K. M. Humayun Kober, Milk and Dairy Foods: Nutrition, Processing and Healthy Aging, CRC Press, 2024, Ch. 9, Concentrated Dairy Food: Condensed Milk, p. 218 (Google Books page read)
- FTN books on disk: Condensed and Dried Milk, Dairy Processing Handbook by Bylund (agrimoon dairy series).
