Having difficulty with How To Prevent Milk From Curdling? Who does not love white sauce pasta or tomato soup? But these recipes require milk in it. Many sauces and soups need to be reduced and thickened.
The desired consistency can be achieved by gently cooking and simmering. If you are using milk in the recipe then boiling or simmering can cause curdling. Although, curdled milk is safe to eat but it is not appetizing enough.
So, if you want to eat white sauce pasta or alfredo then you need to find an answer to this question “How to prevent milk from curdling?” Keep on reading this article for multiple steps solution which will prevent your milk from curdling. Then keep on reading this article.
Why milk is curdled?
Milk is made of butterfat, proteins and water. The protein molecules move independently in freely in the liquid. These protein molecules are the reason for colloidal solution of milk. They reflect light and give off the white color of milk that we see. Most of the time protein moves randomly and in opposite direction from each other. But when the pH of the solution is changed, these protein molecules are attracted to each other and are coagulated or when milk is boiled, all the three ingredients separate.
Protein coagulate and separate from water which in turn causes the curdling of the milk. The same technique is used for making cheese. The protein coagulates and milk forms a curdle that floats on the surface like translucent whey. The solid milk is coagulated through cooking and after that rennet enzyme is added. Once it is done, excess liquid is drained out. If you ever cook cheese and see oil forming on the surface then know it is emulsion that is breaking away. This curdling happens at warm temperature then cold temperature. For soup or sauces, you should not use curdled milk. As it should be consistent and smooth.
Tips and tricks to avoid milk from curdling:
Moreover, you can use following tricks and tips to avoid your milk from curdling:
Do not boil it:
Boiling is the main reason behind curdling of milk. Not just boiling but also heating it on high flame. Even if your milk does not come to boil but the high heating can cause curdled milk. In order to prevent milk from curdling, you should heat it at medium or low flame.
Stabilize the milk using starch:
For over the decades, starch has been used for preventing milk from curdling. You can use cornstarch or flour in your soup or sauces before adding milk. Add flour in sauces to prevent curdling and cornstarch in soups to avoid curdling. It will thicken the consistency, stabilize the milk emulsion and will change the makeup of liquid.
Avoid using strong acidic ingredients:
If your sauce or soup recipe contains acidic ingredients such as wine, tomatoes, lemon juice etc. then curdling is the fate of milk. You can change the fate of milk by adding starch along with the acidic ingredients. Starch will countereffect the acid. For example, if you are making Carrot ginger soup, you need to add little starch with all the spices to prevent your milk from curdling.
Use salt at the end:
Salt is another ingredient that causes the curdling of the milk. But salt is used in each and every soup and sauces. So, how can you stop using salt in order to prevent your milk from curdling? You cannot do that and you should not do that. Instead of adding salt while cooking or reducing the sauce while sat is in it, add the salt once the cooking is done. Moreover, it is a good habit of adding seasoning in the end and you should get into this.
Temper or heat the milk:
It is the basic culinary or cooking rule that you should never add cold milk into the boiling liquid. Instead of adding the cold milk directly, whisk the small portion of milk with cold liquid. This process is known as Tempering. Or you can save yourself some time and heat the milk in pan and add it into the liquid that is cooking.
Use cream instead of milk:
If you do not want to go through this hassle then simply use cream instead of milk in your sauces and soups because the dairy products that have high quantity of fats are less prone to curdling such as whipping cream or heavy cream. Even restaurants use creams in their soups and sauces instead of milk because it will boil in the liquid without curdling. Moreover, cream has more flavor and consistency then milk. If you do not want to use high fat ingredient such as milk then you can also use 2% milk. It has less chances of curdling than whole milk.
Reasons behind curdling of milk:
We have all seen lumpy and unappetizing old milk pour from jug or when vinegar or lemon is added to the milk. The smooth and creamy milk will turn into unappetizing, lumpy and floaty with the addition of acidic ingredient or rapid heating. Although curdled milk looks bad and sometime signifies spoilage but it is not bad thing and can be used to make more delicious dishes such as cheese. Milk curdles due to many reasons such as:
Spoiled milk:
Milk contains bacteria whether it is pasteurized or not. The bacteria feeds on sugar in the milk which is Lactose and during digestion of sugar they produce byproducts called Lactic acid. As the temperature of milk drops further, the quantity of lactic acid increases which makes the pH decreases and causes lumps in the milk. The sour smell in the milk is due to lactic acid and these lumps characterizes the spoilage of milk. In order to avoid spoilage of milk due to bacteria, make sure you always put milk back into the fridge to maintain the normal temperature.
Lemon juice and vinegar:
We all are very well aware what a drop of vinegar or lemon can do to milk. These two ingredients cause the milk to curdle but sometimes this does not happen. The reason behind it is that curdling is a chemical reaction which depends upon temperature. If you add vinegar or lemon into warm milk then it will curdle almost immediately but if it is added to cold milk then curdling will take some time. These ingredients are added into the milk to produce buttermilk for many recipes.
This same chemical reaction is used for making cheeses like ricotta and paneer. The milk is heated at certain temperature and vinegar or lemon is added in it. Once the milk is curdled, the coagulated proteins is separated from the liquid whey and round cheese shapes are made of these proteins. Curdling is a useful process in the situation where cheeses are made out of milk and it has nothing to do with spoilage.
Coffee or tea:
If you are a coffee lover like me then you must have noticed on some occasions that when cold milk is added into hot tea or coffee it is coagulated and curdled. It can be alarming situation especially someone who owns coffee house. Imaging presenting cold milk with coffee or tea to your customers and it end up curdling. It can be seen as spoiled milk. But in this case, it can be half true because as we know coffee and tea is acidic in nature. The acidic nature of coffee and tea cannot curdle the milk that is fresh. But if it is on the brink of spoilage then a little bit of extra acid of these beverages can cause the scale to tip further. The curdling will not be that bad to cause sour smell or taste but it will be evident enough to form coagulation.
Conclusion:
These tips and trick will help you to prevent curdling while cooking soup or sauces. But if your milk is curdled on its own then do not be sad. And you don’t have to throw it. Curdled milk is not always bad because you can make so many things out of it such as homemade goat cheese, paneer, etc. If you are facing similar problem then just drain the liquid whey out and you will have yourself homemade paneer that can be used for various dishes. But do not drink curdled milk because it can cause food poisoning, nausea and cramps in your stomach. It has similar affect as eating or drinking something past the expiration date. Anyhow, I hope you have learned something from this article of mine. See you next time.
Reference:
- “Prevent Cooked Milk from Curdling.” The Spruce Eats, www.thespruceeats.com/prevent-milk-from-curdling-when-cooking
- “How to Avoid Curdling of Milk – Quora.” Quora, www.quora.com/How-do-I-avoid-curdling-of-milk.
