Gelatin & Agar Setting Calculator
Calculate gelatin or agar quantities for desserts and savoury preparations, with conversions between leaf gelatin, powdered gelatin, and agar.
Gelatin and Agar Guide
Gelatin Strength Levels
Gelatin is graded by 'bloom strength' — bronze (125-155 bloom), silver (160-170), gold (190-220), platinum (235-265). Higher bloom = stronger set per gram. Most UK supermarket leaf gelatin: platinum (~2g per leaf). Most powdered gelatin: ~250 bloom. Conversions: 1 leaf platinum gelatin (2g) ≈ 1 teaspoon powdered (~3g — accounting for lower bloom of typical supermarket powder). Standard ratio: 1.5-2% gelatin by liquid weight for standard table jelly. 0.5-1% for soft mousses. 3-5% for firm gummy s
Working with Gelatin
Leaf gelatin: bloom in cold water 5 minutes until soft and floppy. Squeeze out excess. Dissolve into warm (not boiling) liquid — over 80°C destroys some gelling power. Powdered gelatin: 'bloom' first — sprinkle over 4-5× volume of cold water. Wait 5 minutes. Then warm gently to dissolve, then add to main liquid. Important: gelatin does NOT set if added to boiling liquid OR not properly hydrated first. Maximum set develops over 4-12 hours in fridge. Use ASAP after setting — gelatin can 'syneresis
Agar Agar
Agar is a vegan/vegetarian alternative to gelatin, extracted from seaweed. Different properties: sets MUCH firmer per gram (use ~1/3 the amount of gelatin). Sets at higher temperature (~40°C vs ~15°C for gelatin). Stable at room temperature once set. Less melt-in-mouth — has more brittle texture. Standard agar ratio: 0.5-1% by liquid weight for standard set. Method: agar must be boiled to activate — bring to rolling boil for 2-3 minutes. Then pour into mould. Agar flakes: need ~3× more than powd
What Prevents Setting
Fresh pineapple, papaya, kiwi, fig, ginger, paw paw: contain bromelain or papain enzymes that destroy gelatin protein. Always use cooked or canned versions. Excess acid: lemon juice, vinegar weaken gelatin set. Use more gelatin OR balance with sugar (sugar strengthens gelatin set, paradoxically). High alcohol content: weakens set. Use ~50% more gelatin for spiked jellies (jelly shots). Too much fat: prevents proper dispersion — emulsify carefully. Solution to gelatin failure: re-melt gently to ~
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