diced fresh paneer

The Science of Making Paneer + How To Guide

If you wanted to make cheese at home, but never got to it. Why not start making paneer? Paneer is one of the easiest cheese to make. All you need to make this Indian cheese are milk and acid. The resulting cheese is firm, can be fried easily, and is ready in just a few hours. How it works exactly? That’s what we’ll be digging into.

Paneer starts as buffalo or cow’s milk

Paneer is most commonly made from two different types of milk. The most common, and in many regions seen as the superior variety is made from buffalo’s milk. Alternatively, paneer can also be made from cow’s milk, or a mixture of the two.

And is made by curdling milk

To make paneer from milk you need to curdle the milk. During curdling the casein proteins in the milk start to form large clusters. They clump together, incorporating some other components such as fats. These large curds float in the remaining water, which is from then on called whey.

To make paneer, you simply remove the curds from the whey, press them together slightly and the cheese is finished, as you can see in the video below.

With an acid

Milk is made up of mostly water, with a few percent fat, proteins and sugar (lactose). The key component that allows milk to be made into cheese are the proteins, more specifically, the casein proteins.

Casein proteins are a very special type of protein. It’s what sets animal milk apart from plant based milks such as oat or almond milk. These proteins can withstand heat very well. However, they cannot withstand (strongly) acidic conditions. So, by adding an acid, you can destabilize milk and cause it to curdle.

By adding acid to milk you can transform milk into paneer. Aside from paneer, many other cheeses use this mechanism in some way or shape to transform milk into cheese.

The science of curdling casein

So let’s zoom in a little more closely and see what happens. Casein proteins organize themselves in milk in quite a special manner, in so called micelles. These structures are several micrometer in size. They’re small, you can’t see them with the naked eye.

However, if milk becomes too sour, these micellar structures are no longer stable. The acid causes the casein proteins to start forming even larger structures. These structures are visible to the eye and are called curds. By gathering the curds together and pressing out excess water you make cheese!

Did you ever notice that spoiled milk also contains little pieces? This is because spoiled milk has turned sour and the acidity causes the casein to curdle as well! An other way to curdle these proteins is through the addition of rennet, an enzyme.

freshly pressed paneer

How to make paneer

The process to make paneer consists of just four steps:

  1. heating the milk
  2. curdling the milk with acid
  3. separating the curds from the whey
  4. pressing the curds

All steps can be done within an hour, depending on the size of your batch and the desired firmness. So let’s have a closer look at each. For this article, we assume that the milk has already been pre-treated. So it’s been pasteurized or sterilized and possibly also homogenized (a process in which all fat droplets are made into the same size).

Step 1: Heating the milk

In large scale production processes, the milk is heated to a specific temperature, well below the boiling point of water, around 80°C (176°F). Milk may be held at the set temperature for some time as well, depending on the conditions. However, in smaller sized productions it’s easiest to just bring the milk to the boil (100°C, 212°F). That way you can be certain the milk is homogeneously warm.

This heating step is crucial for a few reasons. First of, it can help kill of microorganisms. However, if you plan to eat the paneer shortly after making it this is less important, especially if you also plan to fry/cook the paneer.

Secondly, the heating steps helps to start destabilizing some structures within the milk. This makes it easier to curdle the milk and results in a better yield. Keep in mind that the curds are separated from the whey at the end. The more fats, proteins, etc. are incorporated into that curd, the more cheese you can make from the same volume of milk!

Thirdly, the acid can do its job a lot faster in hot milk than in cold milk. As a matter of fact, you can add a reasonable amont of acid to cold milk without anything happening at all. Add that same amount to hot milk and it will likely curdle immediately. The heat makes molecules in the milk moves more quickly and thus curds to form faster.

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Step 2: Adding acid

Milk starts to curdle at a pH level of approximately 4.6 As such, you need to add enough acid to reach this acidity. A wide range of acids can be used to get the job done. Lemon juice, citric acid, vinegars, tartaric acid, but also sour milk or yogurt they can all work.

The type of acid used can impact the final texture of the paneer. A strong acid (e.g. vinegar) will make a firmer paneer, whereas a weaker acid (e.g. yogurt) will make a softer paneer.

How much acid you need depends on the exact composition of your milk, the temperature and the type of acid you use. It is best to keep in mind that your ingredients might deviate slightly from those used by someone in a recipe, so you might need to adjust.

Curdling happens almost instantaneously. Once it gets going, you will need to stir for a few minutes to ensure all curds have formed well. However, don’t stir too vigorously. Larger curds give a softer, more moist paneer whereas very small curds can make a dry paneer. The smaller ones simply can’t hold onto water that well.

Even though you add acid to milk to make paneer, paneer itself isn’t sour. It simply doesn’t contain enough acid to actually taste sour.

milk + vinegar experiment-1
Demonstrating the effect of vinegar on a class of warm milk. Notice the stark difference between pure milk and that with 1,5 tsp of vinegar.
Why milk changes colour when making paneer

Curdled milk is no longer white, instead, it turns slightly yellow, maybe translucent. The reason milk itself is white is again because of those casein proteins. Their micelles, as well as the fat droplets in milk scatter and reflect light. This causes our eyes to perceive milk as white. Once these micelles are gone and all part of the curds, the remaining liquid is pretty much ’empty’. It looks more like water.

The curds that have been sieved apart from the whey, ready to be pressed.

When making yogurt you also turn milk sour. Why would make that yogurt and not cheese? Keep in mind that making yogurt is a slower process. The milk slowly turns sour. Because of this, the proteins reorganize themselves slightly less abrupt and you end up with softer gels. Also, the conditions and ingredients used are slightly different than those used to make cheese.

Step 3: Filtering

Once the curds are formed, they need to be separated from the remaining liquid, the whey. This can be done using membranes, or a simple cheesecloth. Anything that lets water through, but not the curds themselves. It is a simple physical separation based on particle size.

Pressing down the paneer curds

Step 4: Pressing

To form these still quite lose curds into a block of paneer, they need to be pressed together. Unlike many other cheeses, they don’t need to be pressed as hard, nor as long. A press of 15-20 minutes will often do the job already. And for an at-home batch, a simple thick book is often heavy enough to press the curds together.

Don’t press too much or too long. Pressing will cause water to be expelled from the paneer. To a certain extent this is a good thing, but if too much water leaves the cheese might turn dry.

Once pressed, the paneer is ready for use. Cut it into cubes, possibly marinate it and it’s ready to be fried or baked!

saag paneer
Saag paneer – a spinach sauce with browned pieces of paneer inside.

Properties of paneer

Paneer doesn’t melt or flow when it’s hot. Instead, the structure that has been formed by the acid is quite stable. As such, it’s very well suited for a wide range of applications that involve (deep) frying paneer.

Buffalo vs cow paneer

The composition of buffalo milk is slightly different from that of cow’s milk. For one thing, buffalo milk contains a few additional percentages of fat than cow’s milk does. Also, the casein micelles are slightly larger. All in all, the composition of buffalo milk tends to be slightly more favorable for paneer making than cow’s milk. However, that does not mean cow’s milk won’t work. It’s texture will simply be slightly different and it may well depend on your personal preferences which one you like best.

Whole vs skimmed milk for paneer

When you form the curds from milk the curds will contain all the fat and casein that is present in the milk. If you use skimmed milk there is no fat in the milk. As a result, you will end up with less paneer. Also, this paneer will be drier, the fat (as with most cheeses) makes the paneer softer and more tender.

Paneer is a very versatile cheese. Once you’ve made it you can eat it cold, on a sandwich, or hot in a wide variety of dishes. The firmer the paneer, the easier it is to fry it in some oil. Frying it will dry out the cheese a little further, but the additional crispiness and brown pieces will be worth it. In India you will find paneer in a lot of curries and sauces, keeping the paneer nice and moist.

Why paneer doesn’t melt

Just like several other fresh cheeses such as queso fresco and feta, paneer does not melt. Instead, it holds its shape very well when fried and heated in general. It’s almost the opposite of processed cheeses which have been made to melt easily. This is due to the way paneer is made.

The acid causes the casein proteins to form strong and stable curds. The low pH causes the charges of the proteins to be neutralized, limiting repulsive forces between casein proteins. Curds formed this way aren’t affected by heat, the casein proteins continue to bond together. If anything, the heat will evaporate moisture, causing the paneer to become even firmer.

But paneer can turn dry

The loss of moisture during cooking can have a detrimental effect on the final cooked paneer. By evaporating moisture, the paneer becomes firmer and drier. If you’d cook the paneer for too long it will turn rubbery and dry. It’s why paneer is often added to or cooked in moist sauces, to prevent it from drying out excessively.

How long to store paneer for

Paneer made at home can be stored in the fridge for a few days at most. After that time, yeasts and molds, which are all around us, will start growing on paneer almost immediately.

Store-bought paneer that is vacuum packed for instance has been made in such a way as to delay growth of micro organisms. As a result, you can often store this longer than a homemade version.

freshly pressed paneer

Paneer

Yield: Enough paneer for 2-4 people
Prep Time: 15 minutes
Total Time: 15 minutes

A basic recipe for making paneer, a fresh, hard cheese made with just milk and acid.

Ingredients

  • 1 liter milk
  • 2 tbsp acid*

Instructions

  1. Bring the milk to a boil and take it from the heat once it boils.
  2. Immediately, add the acid and mix in. The milk should start curdling pretty much right away. You will see white curds forming and the liquid itself becomes transparent instead of white. If you see very few curds and if the liquid stays white, add additional acid, 1,5 tsp at a time.
  3. Once the liquid (also called whey) has become clear, pour the mixture over a colander covered with a cheese cloth.
  4. Gently push the curds together and close the cheesecloth. Place the curds on a tray and carefully press down with something heavy, e.g. a heavy pan.
  5. Wait approx. 30 minutes before removing the heavy weight. The longer and harder you press it down, the firmer it becomes.
  6. Once the paneer is ready, store it in the fridge until you're ready to use it.

Notes

*You can for instance use lemon juice, lime juice, vinegar, rice vinegar. The exact quantity of acid you need depends on your milk and your acid. Use visual cues to determine whether you added enough.

References

Harold McGee, On Food and Cooking, p. 64-65 (on melting of cheeses), review

Khan SU, Pal MA. Paneer production: A review. J Food Sci Technol. 2011 Dec;48(6):645-60. doi: 10.1007/s13197-011-0247-x. Epub 2011 Feb 5. PMID: 23572801; PMCID: PMC3551056., link

Kumar S, Rai DC, Niranjan K, Bhat ZF. Paneer-An Indian soft cheese variant: a review. J Food Sci Technol. 2014 May;51(5):821-31. doi: 10.1007/s13197-011-0567-x. Epub 2011 Oct 26. PMID: 24803688; PMCID: PMC4008736. link

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6 Comments

  1. Hi Julie,

    Your post made me think of how paneer made from heavy cream will taste/feel since heavy cream has a higher fat content – thoughts? Also, do you think if there’ll be a difference between paneer made from ultra-pasteurized milk vs pasteurized vs raw?

    PS: I came across your blog today and thoroughly enjoyed reading through many posts. I am on a mission for perfecting ice creams and Hello my name is ice cream is one of my favorite ice cream books! One of the issues I’ve been having with ice cream making is sometimes my ice creams have a buttery mouthfeel, which I know is because of overchurning, even though the total time those ice creams were churning in the ice cream maker were pretty much same as other times when the buttery feel didn’t happen. I have also noticed difference in the buttery mouth feel depending on which brand I was using. Somewhere in there you wrote not to boil heavy cream – I am going to keep that in mind.

    • Hi Preethi,

      So glad to hear that you’re enjoying the blog!

      I like your thoughts on using heavy cream. However, heavy cream contains a lot less casein and so will not curdle as well. Also, there should be enough casein to casein and capture all the fat. In the case of cream, even if there was the same amount of casein there is very likely to be too much fat present for all of it to be caught up in the casein clusters!

  2. Thank you so much! I was persuaded to try making cheese and thought I’d have a better chance at success if I studied the science first.

    Your explanations are excellent and I’m much more comfortable with moving forward now.

    J’y vais a la cuisine!

  3. I often make panner successfully when using supermarket milk but it always fails when I use milk bottle milk from the milkman. Why is this?

    • Hi Steve,

      How does the paneer fail if you make it from milk from the milkman?
      If that milk from your milkman comes pretty much straight from the farmer it will not have been homogenized. As a result, the fat splits from the milk more easily and might not incorporate into your paneer. Would that explain your observations?

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