We’re halfway through the new style series of GBBO, and though it certainly feels the same in a lot of ways, I do miss Mary Berry and her soggy bottom obsession. The holy grail of a crisp pastry shell with no under-cooked ‘soggy bottom’ is what every baker strives for… but no matter how experienced we are at baking, it is still something that can happen, and that can be what puts people off baking pastry.
So why does it happen? Pastry is a simple combination of flour, fat (usually butter) and liquid (usually water), and like all baking there is an exact science behind why and how the ingredients react together to go from gloop to yummy pastry. I was taught that there are basically two things happening in pastry as it cooks – the gluten in the flour is creating the structure and the fat in the butter is creating the texture. But if the fat melts before the gluten has reacted to create the structure it will result in a soggy bottom.
So now you know why it happens… I’m guessing you want to know how to avoid it? Well, here are my top tips for achieving a nice firm bottom every time, no matter the pie or pastry!
No this doesn’t mean close your eyes and hope for the best when you put the pastry in the oven… it means to pre-bake the pastry shell before you add the filling. This method works well for pies and tarts that have quite a liquid filling; just line the pie dish with your pastry as usual then cover with baking paper and add pastry weights or baking beads (usually ceramic balls) that help weigh the pastry down to stop it rising up. The pastry is now sealed, and won’t absorb the liquid.
Brush with egg
We are used to brushing pastry with egg to get that lovely crisp brown shell, but brushing the base with egg acts as a seal between the pastry and the filling. This is a technique that can be paired with baking blind – blind bake the pastry case first, then brush with egg before adding the filling, or you can just brush an uncooked pastry case with egg without blind baking first.
Hot baking tray
This works particularly well for pastry that can’t be baked blind, like pasties or sausage rolls. It can also help with any pie dishes too… simply put a baking sheet in the oven to preheat and then put the pastries or pie dish on top and it helps jump start the pastry baking.
Temperature is key
For success every time, I was taught to make sure your pastry is as cold as can be but your oven is hot – hotter than for cakes or biscuits. When making the pastry, only use very cold butter or fats, then chill your pastry again once it’s made and chill the case again before baking. This helps slow down the fat melting so the gluten can work to form the pastry structure. Check your recipe and oven instructions, but as a general rule, your oven needs to be at GM5/190C.
Use heavy tins
What you use to bake pastry matters. The thicker and heavier the tin or pie dish, the better it retains and conducts heat, so ceramic, glass and thick metal are better than thin tins.
I hope all this has been useful, and given you confidence to try baking pastry armed with some sneaky tricks! For the best chance of avoiding a soggy bottom you could do as I do… a combination of all the above; chill your pastry, blind bake it, brush it with egg and bake it in a heavy pie dish on a hot baking tray in a hot oven… go on, try it and make Mary Berry proud!