Pastry Cream Thickener Calculator
Scale crème pâtissière to any amount of milk — how much cornstarch or flour, egg yolks and sugar you need for a pipeable pastry cream.
How it works
Thickener = (milk ÷ 240) × per-cup × body factor · Cornstarch 20 g/cup, flour 30 g/cup · Body: light 0.8, standard 1.0, firm 1.3 · Yolks ≈ 3/cup, sugar ≈ 55 g/cup
Pastry cream (crème pâtissière) is a custard thickened with both egg yolks and a starch, which lets it be brought to a full boil without curdling — the starch protects the yolk proteins. Cornstarch gives a glossier, more delicate set and less starchy taste than flour, though flour is more forgiving. Firmer versions with more starch hold their shape for piping and tart fillings, while lighter ones are meant to be lightened with whipped cream into a crème diplomate.
Worked example
For 500 ml of milk (≈2.08 cups) at standard body with cornstarch: 2.08 × 20 ≈ 42 g cornstarch, about 2.08 × 3 ≈ 6 yolks, and 2.08 × 55 ≈ 115 g sugar. Whisk, cook to a boil for a minute or two until thickened, then chill with plastic pressed on the surface.
Frequently asked questions
Cornstarch or flour for pastry cream?
Cornstarch gives a silkier, glossier cream with a cleaner flavor and needs about a third less than flour. Flour is sturdier and more forgiving but can taste faintly starchy if under-cooked.
Why is my pastry cream runny?
It was not cooked hot enough or long enough — the starch must reach a boil to fully gelatinize. Return it to the heat and boil, whisking, for a minute or two until it thickens and one big bubble bloops.
How do I make it lighter for a filling?
Chill the pastry cream fully, then fold in whipped cream (this makes crème diplomate). Start with the "light" body so the finished, lightened cream is not too dense.
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This calculator is for educational purposes. Double-check important results before acting on them.