Pie Filling Calculator

The fruit quantity depends on your tin size and how generously you fill it. This calculator fills about 75% of the tin volume, so a standard 23cm (9 inch) dish 4cm deep works out at roughly 1kg of prepared fruit for a well-filled double-crust pie. A shallower or less heaped pie uses less — around 600-700g if you only fill to about half depth. Deeper, mounded American-style pies use more (6 cups, ~1.1kg). Remember to account for prep waste — apple peel and core adds about 25% extra to your buying weight. Adjust the filling fraction in Advanced options to match how full you like your pies.

It depends on the fruit. Tart fruits like rhubarb and gooseberry need about 25-28g sugar per 100g fruit. Sweeter fruits like apple and pear need only 10-12g per 100g. Always taste your fruit first — ripeness varies and you may want to adjust. You can also replace some sugar with honey or golden syrup.

Cornflour is the most common thickener for fruit pies. The amount depends on juiciness and pectin, not just weight. Apple is the least juicy and highest in natural pectin, so it needs the least — about 1.2g per 100g of fruit. Juicy, low-pectin fruits like blueberries, gooseberries and rhubarb need the most, around 2.8-3g per 100g. King Arthur Baking's pie-thickener guide grades fruits this way. Arrowroot gives a clearer result and tapioca starch holds up better to freezing. Frozen fruit releases more liquid, so add a little extra.

For a 23cm pie about 4cm deep, you need roughly 400-450g of shortcrust pastry total for a double crust — covering the bottom circle, the sides and the top circle. The calculator estimates pastry weight from the tin's surface area at 3mm thickness, which is standard for a good pie. A shallower tin needs a little less; rolling thicker for a more substantial crust needs more. As a guide, that is about 250g plain flour to 125g fat plus water for a 23cm pie.

For apple pies, it is best to briefly cook the apple with sugar to drive off excess moisture — this prevents a gap forming between the filling and top crust. For berry pies, you can use raw fruit with cornflour mixed through. Rhubarb benefits from a light pre-cook with sugar to reduce liquid. The thickener amounts in this calculator assume raw fruit filling.