Why does my coconut milk look curdled?

In this blog post, we will answer the following question: Why does my coconut milk look curdled? We will also discuss the differences between cream and coconut milk and the basics of cooking with coconut milk.

Why does my coconut milk look curdled?

Over the past years, the market for these plant based milk alternatives has continually increased and, in the USA alone, reached an annual volume of approximately US$1.8 billion. From a global perspective, the projected compound annual growth rate is higher than 10%, and thus the world market is estimated to surpass US$26 billion by 2023 (1).

The coconut milk looks curdled when the fat separates from the water, but it is still safe to consume. It is normal for coconut milk to separate when it is resting, and not only the one we buy canned in the supermarket, but also the coconut milk that we can make at home. Besides, coconut milk coagulates readily upon heating to 80°C or 176°F (2).

What separates coconut milk is the fat from the water, you know that it is the natural tendency, just as it happens with cow’s milk and others, the fat (cream) rises to the surface.

Coconut milk is naturally stabilized by proteins and phospholipids. The aqueous phase of coconut milk emulsion contains some proteins, which act as an emulsifier to stabilize oil droplets. As with all emulsions, coconut milk is not physically stable and is prone to phase separation. Natural coconut milk will separate into a cream and serum layer within 5 to 10 h of manufacture (4).

Hydrophilic and hydrophobic groups of these molecules can minimize the interfacial tension among two phases and promote the dispersion of oil droplets in the aqueous phase, thereby enhancing emulsion stability. Processing operations, which tend to produce smaller globules, are expected to yield more stable emulsion. When coconut milk was added with whey protein isolate as stabilizer, it could be heated at 70°C (158°C) without collapsing (3).

What to do then with the curdled coconut milk? Well, it depends on what you are going to use it for, for example, if you are going to make a curry or a recipe that simply indicates that you need a certain amount of coconut milk, what you have to do is pass it on to another container and beat well until you get an emulsion. 

When you get used to using coconut milk in the kitchen, you also tend to get used to shaking the can vigorously before opening it and thus it is already emulsified.

Now, there may be occasions when a recipe indicates that coconut cream is needed (unsweetened), this is another product that is also marketed in a can, whose characteristic is that it has less water content than milk coconut, that is, it has more fat. 

Well, an alternative to this product is to use only the solid part of the can of coconut milk, leaving the ‘water’ for another preparation. To make it easier to recover the fat from coconut milk, it is recommended to leave the can in the refrigerator for a while before, as the cold solidifies the fat and it is easier to recover it simply with a spoon.

Why does coconut milk curdle? 

Coconut milk curdles as a result of the denaturing of protein when it is heated. This protein changes its nature and interacts differently with the contents of milk, producing visible “curds”.

Coconut milk is essentially an oil-in-water emulsion, stabilized by the naturally occurring proteins (globulins and albumins) and phospholipids (for example, lecithin and cephalin) (4). Emulsions are thermodynamically unstable and various processes lead to changes in the drop size-distribution and/or emulsion structure. The stability of the emulsion can be lost due to many factors, such as protein concentration and adsorption, drop size, electrolyte concentration, pH, thermal treatment and time of shelf-storage (5).

The change in nature results in a change in the binding ability of the protein.

How do you fix separated coconut cream?

In the case of coconut milk, if you can clearly see the coconut cream on top, the best solution is to shake the bottle/container before opening it. This happens because of the difference in density between the cream and the milk. Such milk is totally okay and the problem can be solved with either gentle stirring or shaking the can.

Is it bad if canned coconut milk is separated?

No, canned coconut milk that is separated does not mean it has gone bad. Coconut milk contains fat that often solidifies at low temperatures. Water-based constituents often settle down at the bottom of the can fat floats. It is totally normal, shake the can before opening or stir after opening to remix the separated layers.

Can coconut milk curdle?

Yes, coconut milk can curdle. It usually forms large chunks or curds when left unstirred for a long period of time. This curdling does not mean the milk has gone bad. It simply happens due to the constituents of coconut, especially water and fats.

It is common practical knowledge that heating and homogenization affect the stability of coconut milk emulsions. Thermal processing is an effective means of extending the shelf life of coconut milk. Coconut milk is often mixed with emulsifiers and/or stabilizers before a homogenization process (4).

Know the difference between cream and coconut milk

Coconut cream is the pure extract obtained only from pressed coconut: you grate fresh coconut, you put the material obtained in a press, you press very hard – and the juice that comes out is the coconut cream.

To get the milk, just add water to the remaining solid coconut extract, and squeeze again.

Cream or milk: both are good, however, the uses are not the same. The cream is much richer, fuller, and longer in the mouth. Milk is more liquid, fresher – know how to use one or the other wisely.

The names “cream” or “milk” are not registered, manufacturers can mark anything on their labels: therefore always check the water content of the product you buy: if you have 99% coconut, this is cream. If you have 40 to 50 percent water, it’s milk.

However, the Food and Agriculture Organization of the United Nations has published a standard applied to packaged aqueous coconut milk and coconut cream products. According to this standard, aqueous coconut products are classified into 4 categories: light coconut milk, coconut milk, coconut cream and coconut cream concentrate depending on total solids and total fat content. The standard defines coconut milk as having 12.7 – 25.3% total solids and 10% fat and coconut cream as having 25.4 – 37.3% total solids and 20% fat (6).

And above all, choose a product without additives, sugar, or flavoring. Coconut and water, that’s all you need to find!

Cooking with coconut milk

Coconut milk is very sweet, you have to wake it up with precise, complex flavors. Despite its apparent simplicity, it is therefore quite difficult to improvise it. The solution: read the recipes carefully, and stick to the dosages – and if a certain spice is missing to complete the dish, well we’re going to buy them, you need what it takes to come out the best.

If while cooking the coconut sauce seems too heavy or too fatty, there are ways to improve it. To revitalize your preparation, add acidity and freshness (lime, various herbs).

You can also increase the depth of taste by adding salty elements – Nuoc Mam in particular if you have it, which will shake up the sweet side of coconut milk and give it depth.

Finally, if you like strong flavors, do not hesitate to spice up your preparations: the combination of peppers and coconut has been proven, they must be paired.

 If there was just one rule to remember, it would be this: does coconut milk at the minimum. There is always a strong temptation to add a drink, but the balance is quickly upset, so if you are looking for finesse, you should avoid overloading with coconut milk.

An example: the famous Thai soup Tom Kha Kai is often much too loaded with us, while the original version contains very little coconut milk, just a touch. The main broth, fine and fragrant, is the central character of this wonderful soup. 

The coconut milk only emphasizes the fresh and delicate flavors – and in the end, we get a wonderful and fragrant alliance, one that makes it definitely impossible to do without coconut milk on our plates.

Conclusions

Coconut milk is a very good addition to fried sauces and is an interesting alternative to thickeners in sauces such as flour and cornstarch. Coconut milk is a fairly thick liquid that has a fine and creamy texture and a sweet taste to the actor. It is prepared by straining the water from the coconut pulp and does not contain the milk of animal origin.

If you have any questions or comments on the content, please let us know.

References

1. Tangyu, Muzi, et al. Fermentation of plant-based milk alternatives for improved flavour and nutritional value. Appl microbiol biotechnol, 2019, 103, 9263-9275.
2. Waisundara, Viduranga Y., Conrad O. Perera, and Philip J. Barlow. Effect of different pre-treatments of fresh coconut kernels on some of the quality attributes of the coconut milk extracted. Food Chem, 2007, 101, 771-777.
3. Patil, Umesh, and Soottawat Benjakul. Coconut milk and coconut oil: their manufacture associated with protein functionality. J food sci, 2018, 83, 2019-2027.
4. Tangsuphoom, Nattapol, and John N. Coupland. Effect of heating and homogenization on the stability of coconut milk emulsions. J food sci, 2005, 70, e466-e470.
5. Tcholakova, Slavka, et al. Coalescence stability of emulsions containing globular milk proteins. Adv Colloid Inter Sci, 2006, 123, 259-293.
6. CODEX STAN 240, 2003. Codex Standard for Aqueous Coconut Products-Coconut Milk and Coconut Cream. FAO/WHO Food Standards Programme.