Me and maths aren’t usually friends. But I’ve been intrigued to find that there’s a lot of maths that can explain the fluffy lightness of rough puff and puff pastry.
The folding method and total number of folds for puff pastry is crucial to creating the many layers. Mille feuille means thousands leaves in French, and it’s literally possible to create more than a thousand (2187 to be exact) in just 7 ‘turns’. Although making 6 turns, or 729 layers, is usually the norm for recipes.
The process of building puff pastry is to roll out into a rectangle and fold the bottom third of the middle third, then the top third over the other two, and then turning 90˚ (or -90˚ – it doesn’t matter as long as you’re consistent throughout) as in the image below. This process is one ‘turn’.
The first turn makes three layers from the initial rolled out sheet of pastry.
Turn two or more is where the maths comes in as every turn creates three layers out of the pastry block you already have.
For the first turn, it’s 3×1 making 3 layers.
For turn 2 – you’ve already got three layers so when you do the folds the layers are mutilplied 3×3 or 3x² which results in 9 layers.
I’ve drawn a sketch to show what’s happening a little more clearly…
|A finished 6 turn block of puff pastry (this lot was made for the palmiers recipe)|