Why pastry cases shrink – and why blind baking is the answer

You have rolled, lined, chilled, and then opened the oven to find the sides slumped and the base puffed up. Shrinkage happens because gluten, the protein network in flour, contracts when heated. Fat melts, water turns to steam, and the pastry pulls inwards. Blind baking – baking the empty case with weights – sets the structure before your filling goes in. It also creates a watertight barrier, so soggy bottoms become a thing of the past. The trick is not just blind baking, but doing it with cold pastry, proper lining, and enough weight.

Chill twice for a shrink-proof shell

The single most effective defence against shrinkage is cold. Cold pastry is relaxed pastry. After you make your shortcrust, flatten it into a disc, wrap it, and chill for at least 30 minutes. Then roll it out, line your tin, and chill again – 15 minutes in the freezer is even better. Why? Chilling solidifies the fat, so it does not melt before the gluten sets. It also relaxes any gluten you developed while rolling. A metal tin chills faster than ceramic or glass, and it conducts heat more evenly, giving you a crisper base. If you are short on time, pop the lined case in the freezer while the oven preheats.

Lining and weighting: the right technique

When lining, never stretch the pastry. Lift it into the tin, letting it settle into the corners. Press gently against the sides – if you pull or tug, it will spring back in the oven. Prick the base all over with a fork. This lets steam escape. Then line with crumpled baking parchment or foil. Crumpling makes it flexible, so it fits into every fluted edge. Fill right to the top with baking beans, ceramic beads, or uncooked rice. A thin layer will not hold the sides up. For deep fluted tins, fill to the very rim.

• Use a metal tin if you have one – it gives the best heat transfer.
• Never stretch pastry when lining; let it fall into the corners.
• Prick the base with a fork to release steam.
• Fill weights to the top, not just a scattering.

The two-stage bake

Bake at 180°C fan (200°C conventional) for 15–20 minutes with weights, until the edges are set and pale gold. Remove the lining and weights carefully. Return the case to the oven for 5–10 minutes, until the base looks dry and sandy. If your filling is wet, brush the inside with beaten egg or egg white and bake for 2 minutes more. This seals the pastry. For a fully baked case, continue until golden brown. Always preheat a baking sheet and place the tin directly on it – the hot metal gives the base a head start and prevents a soggy bottom.

Fixing soggy bases and stubborn shrinkage

Soggy base? Your first bake was not long enough, or your filling is too wet. Blind bake longer, and do not skip the hot baking sheet. Shrinking sides? You may have overworked the pastry, or not chilled it enough. Another trick: after lining and chilling, trim the excess pastry with a sharp knife, leaving a small overhang. The overhang shrinks back to the rim. Also, do not stretch the pastry when you press it into the flutes. If the sides still slip, chill the lined case for 20 minutes, then bake it from cold – never let it come to room temperature before it goes in the oven.

British flours and fats for a reliable shortcrust

British plain flour is ideal for shortcrust. It has a lower protein content than strong bread flour, so it does not develop tough gluten. For a crisp, short crumb, use cold British butter and a little lard or vegetable shortening. Lard makes the pastry flakier and helps it hold its shape. If you are using wholemeal British flour, add a tablespoon or two of water – the bran absorbs liquid. Rest the pastry well. And remember: the colder your ingredients, the less shrinkage you will see. Cold hands, cold pastry, hot oven – that is the golden rule for perfect pastry cases every time.