close up of puff in the puff pastry

Puff pastry – Science of flaky layers

Making puff pastry sounds very daunting to a lot of home bakers. You can see contestants struggling with it on tv baking shows, like the Great British bake off. And why make it, when you can buy it?

It took me a long time as well to finally give it a go. Main reason being that I wanted to better understand how puff pastry works and what’s better than making your own to find out!

What is puff pastry?

As the name says: puff pastry is pastry that puffs. More precisely, it puffs in the oven, when it’s being baked. It is very similar to a croissant dough, however, you don’t use yeast in your dough. If you look closely at a well cooked piece of puff pastry you can identify a lot of different layers of very thin flaky pastry, with layers of air in between. Even in uncooked pastry you can see those layers alongside the side of the pastry.

Each of those layers consists of a thin layer of dough (mostly flour + water) sandwiched between two layers of fat (often butter or margarine). The fat prevents the dough layers from interacting with one another, so they can’t form one large structure, as would happen when you make a bread for instance.

When you put puff pastry in the oven, the fat in between those dough layers melts and it will sit in the actual dough itself. Also, moisture, from the butter as well as from the dough, starts evaporating as the pastry becomes warmer. The air can easily sit in between those dough layers since they weren’t holding onto one another anyway. As a results, the space between the layer expands and you get those air pockets.

Fat in puff pastry

Puff pastry contains a lot of fat, it needs the fat to form all those layers. A commonly used fat is butter, but margarine is a good alternative. The fat content in puff pastry is at least half the weight of the flour, but it can be as high as 1:1.

rolled out dough for french croissants
A croissant dough, so slightly different from puff pastry, but the concept is very similar.

How do you make puff pastry

We’ve got a recipe for puff pastry at the bottom of this post, walking you through all the instructions to do it at home. The process for making it at home is very similar to how manufacturers do it (as we will see later), although they will automate part of the process.

Those layers are the most important part of puff pastry. You make them by folding a dough with fat inside several times. In order to create them you start by making a simple dough of water and flour (and a few other ingredients, this depends on the recipe). This dough should be nice and flexible since you’ll be stretching it quite a bit as you go.

Next you need to incorporate the fat. There are several techniques to do this. For instance, you can lay a slab of fat on top of a rolled out piece of dough (the technique we use in the recipe at the bottom of this post). Another technique is to use pieces of butter that you spread around the dough, or you can even use a food processor to mix the (frozen) fat into the dough. The most important bit of this step is to ensure that the fat is evenly distributed throughout the dough, while not melting. Now that the fat is in you will have dough/fat/dough layers in your dough, although you might not always see those clearly.

The math of folding

If you would just do a simple fold over the middle, you will be doubling the number of layers. More often though, you will fold in a book fold (=no. of layers x 4) or a triple fold (bit like you would fold a letter for an envelope). If you would do three book folds you will end up with: 1 x 4 x 4 x 4 = 56 layers already!

Puff pastry folds infographic
Some examples of how you could be folding your puff pastry. Top left you see the bookfold, you create 4 layers out of one with this fold. Bottom right is how you would fold a letter. One the bottom left we illustrated butter inside the dough to help you visualize the number of layers!

The importance of temperature

In order to make all those layers it is very important that the fat in between the dough layers remains solid. Once the fat starts melting it will sit within the dough and your layered effect can disappear. Therefore, you will find that a lot of recipes call for cooling your dough in between.

The importance of the right fat

Originally, the fat used for making puff pastry was butter. Mostly this was out of necessity, we didn’t have other solid fats that would behave in a similar way. Pork fat (lard) for instance is a lot softer than butter at room temperature and has a distinct (often not desired) flavour.

Nowadays, a lot of alternative fats are available though in the form of various margarines. Margarines are made of vegetable oils that have been hardened to behave more like butter. Because of this specific process manufacturers are able to control the properties of the margarine quite well, resulting in fats that are optimal for puff pastry making. For instance, they melt might less easily at room temperature.

Storing puff pastry

You can store freshly made puff pastry in the freezer for weeks’ on end. It is most important to ensure all those layers stay separate. Once you thaw the dough, it is ready for use.

Once puff pastry has been baked though it becomes harder to store. Puff pastry is best when it is crispy. however, as soon as it comes out of the oven it will start losing some of that crispiness. The moisture from the air will sit in the pastry layers, softening it over time.

Making puff pastry in a bakery

Puff pastry is made in a very similar way in a bakery as it would be at home. However, the bakers will have some convenient tools at their disposition. They can use a special rolling table for instance on which to roll out the dough with fat inside to prepare it for the next fold.

The video below is a great example of making puff pastry in a bakery. I would recommend playing it at twice the speed. Notice how flexible the dough is and how it looks smoother after rolling and folding several times. Also see how the baker takes care to fold it back into a nice rectangle every time. This way you don’t end up with parts that have less layers.

Example of rolling puff pastry in a bakery environment. Still a lot of rolling, but luckily we don’t need to use a rolling pin anymore.

Making puff pastry in a factory

Now that you know the basic way how puff pastry is made, you will be able to recognize the process at larger scale as well, because it follows very much the same steps. You start by making a dough, you add a slab of butter, fold the dough closed and then fold it several times. You will notice that the techniques they use are slightly different since machines have to process the dough in a continuous manner. So, instead of using a single book fold for instance, the machine uses a continuous back and forth folding of dough ensuring that it can continue running.

This video shows of a production line for puff pastry. The start of the video shows the basic steps of the process that you will recognize by now. After those first few minutes it continues to show a lot of ways in how the pastry can then be formed which you’re free to skip watching.

Puff pastry

Puff pastry

Making your own puff pastry isn't something you do in a few minutes. But, it is not as daunting as you might think either. You just need 3x 10 minutes and a lot of waiting in between.

The recipe makes enough puff pastry for tarts for 6 people. Since making the puff pastry is most of the work, you might want to make the full portion even if you only need half and just freeze the rest.

This recipe is written with a kitchen at regular room temperature (about 20C). If it's a lot warmer in your kitchen you have to take care to keep everything cold and you may want to cool down your ingredients more and longer in between steps.

Prep Time: 4 hours
Cook Time: 20 minutes
Total Time: 4 hours 20 minutes

Ingredients

  • 500g flour
  • 1 egg
  • 290g water*
  • 1/8 tsp salt (or to taste)
  • 345g butter

Instructions

  1. In a bowl, weigh out the flour, egg, water and salt. Knead together into a smooth dough. There is no need to form a lot of gluten, so you don't have to knead it as extensively as bread. Knead it until it has come together into a soft flexible ball. Add more water or flour if you need it. The final dough shouldn't be sticky.
  2. Cover the dough and leave it to rest for 15 minutes. If it is warm in your working area, store it in the fridge. (You can also leave it up to 2 hours, if you're planning on leaving it for longer, put it in the fridge).
  3. Take your butter and place it in between two large sheets of plastic foil. Using a dough roller, smash the butter into a flat disk (approx. 1/2 cm thick). Try to keep it in a rectangular shape, that will make the next step easier. Store the butter in the fridge until you use it.
  4. Roll out the dough into a rectangle about twice the length of the butter slab.
  5. Place the butter slab on one side of the dough and fold the other half of the dough over the slab. Close of the edges of the dough to ensure that no butter is sticking out.
  6. Roll out the slab into a long rectangle again. Make a bookfold, along the long side of the dough you fold the top quarter inside, same for the bottom quarter. Your rectangle should now be half the size it was at the start with the two pieces of dough coming together in the middle. Now fold it double one more time.
  7. Wrap the dough in a plastic bag or plastic foil and leave to rest in the fridge for at least 30 minutes. No problem to leave it in for a couple of hours until you go to the next step.
  8. Take the dough out of the fridge and immediately start rolling it into a rectangle again. You want to have the dough turn 90 degrees compared to how you folded it up.
  9. Repeat the bookfold from the previous fold.
  10. Turn the dough 90 degrees again, one quarter, roll out into a long rectangle again and fold again.
  11. Cover it back in the plastic and leave to rest in the fridge for another 30-60 minutes.
  12. Repeat the rolling and folding, do it two times again.
  13. Place it back in the fridge, covered in plastic. It is now ready to use. If you want you can freeze it until you're planning to use it. Otherwise, leave it to rest at least another 30 minutes in the fridge before rolling it out.
  14. How to bake it depends on the recipe, we baked it at 200C (400F) for 25 minutes until it was nice and crispy and a light brown. You should see the sides puffing up.

Notes

* The amount of water will depend somewhat on your flour. If you're not sure about your flour hold back 30g of water and see whether it comes together. Only add the water if you notice you've got too little.

You can use puff pastry for a lot of things, but if you're looking for a nice simple savoury tart, you might want to consider the following. Take a small pumpkin (choose a variety you look, we used the generic orange type) and cut it into small pieces. Bake in the oven at 180C (350F) for about 30 minutes until soft and tender. Mix the pieces with 30g of goat's cheese, big handful of walnuts and 50g cranberries (sliced in half). Roll out half of the puff pastry and cut into 8 smaller pieces. Add a generous portion of the topping but take cake to keep the sides free to get that real crunch. Back in the oven at 180C (350F) for 25-30 minutes until the pastry has turned a nice light brown.

Sources

Baking matters, puff pastry, link

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