Can I use gelatine powder instead of leaves?

Yes. Each gelatine leaf is roughly equivalent to 2g of powdered gelatine. So 12 leaves equals about 24g of powder. Soak powder in cold water (5 times its weight) until bloomed, then add to the hot syrup in the same way.

What temperature should the sugar syrup reach?

For marshmallows, heat the sugar syrup to 127°C (firm ball stage). This gives the right concentration for a marshmallow that sets firm enough to cut but stays soft and fluffy inside. Use a sugar thermometer for accuracy.

Why do marshmallows need egg whites?

Egg whites are optional but highly recommended. Whipped egg whites create a lighter, fluffier texture and give the marshmallow a brighter white colour. Some recipes omit them, but the result is denser and chewier.

How do I stop marshmallows sticking?

Dust the tin generously with a 50:50 mixture of cornflour and icing sugar before pouring in the marshmallow mixture. Once set, dust the top and cut sides with the same mixture. Use a sharp knife or pizza cutter oiled with a neutral oil.

How long do homemade marshmallows keep?

Stored in an airtight container dusted with cornflour and icing sugar, homemade marshmallows keep for up to 2 weeks at room temperature. They should not be refrigerated as they absorb moisture and become sticky.

Can I flavour marshmallows?

Yes, add flavouring and food colouring at the very end of whipping. Popular options include vanilla extract, rose water, peppermint, freeze-dried fruit powder, or cocoa powder. Add about 1-2 teaspoons of liquid flavouring per 20x30cm batch.

BakeCalcs

Marshmallow Calculator

Calculate gelatine, sugar, and water quantities for homemade marshmallows by tray size.

Tray Size

Select the tray size for your calculation

How We Calculate This

This calculator scales a marshmallow recipe based on tray size. The base recipe uses gelatine for setting, a boiled sugar syrup for structure, and optional egg whites for lightness.

Base Recipe (20x30cm tray)

Gelatine: 12 leaves (or 24g powder)
Sugar: 500g caster sugar
Water: 200ml (for blooming gelatine) + 125ml (for syrup)
Egg whites: 2
Dusting: 30g cornflour + 30g icing sugar

How It Scales

Quantities scale proportionally based on the tray area compared to the standard 20x30cm (600 cm²) tray. A larger tray needs more mixture proportionally.

Frequently Asked Questions

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Last updated: February 2026

All calculations are based on standard ratios and conversions. Results may vary with specific ingredients, equipment, and conditions.