How Do I Substitute Agar Powder for Gelatin?

Quick answer (TL;DR): Use 1 teaspoon (≈ 2 g) of agar powder per cup (240 ml) of liquid to replace the gelling power of one standard 0.25-oz (7 g) gelatin envelope. Agar sets at room temperature and gives a firmer, vegetarian gel.


Left: 1 tsp Cape Crystal Agar Powder per cup—vegan, room-temp set.
Right: Classic pork gelatin—softer body, needs refrigeration.

Why Agar Needs a Different Ratio

Gelatin is an animal collagen that melts at body temperature (≈ 35 °C), giving that classic “melt-in-the-mouth” wobble. Agar is a seaweed polysaccharide that sets while cooling to about 40 °C and doesn’t re-melt until it hits the 90 °C range—so you need less of it to get a firm bite.

Quick Ratio Table

Texture target Gelatin amount* Agar powder equivalent
Soft set (panna-cotta) ½ tsp ¼ tsp (≈ 0.5 g)
Firm dessert jelly 1 tsp 1 tsp (≈ 2 g)
Sliceable terrine / aspic 2 tsp 1½ tsp (≈ 3 g)

*Based on one cup (240 ml) of liquid.

How to Use Agar Correctly

  • Hydrate hot: Whisk agar into your liquid and boil for 60 s to fully dissolve.
  • Pour & set: Transfer to molds; agar will gel between 35 – 40 °C (no fridge required).
  • Re-meltable: If you need to adjust texture, simply reheat to ≥ 90 °C, add more liquid or agar, and reset.
  • Dairy & acid tips: Add 20 % more agar in high-acid (pH < 4) recipes; dissolve in water first before adding lemon juice or vinegar.

Cape Crystal Agar Powder – high-clarity, fast-set 200 gelling-strength.

FAQs Within the FAQ

Can I swap agar flakes for powder?

Yes – use roughly 3 × the weight of flakes because they are less dense (or crush them to powder first).

Why didn’t my agar dessert set?

It likely never reached a full rolling boil; undissolved granules won’t gel. Re-boil for one minute and reset.


References & Further Reading

  • Mucha, O. & Giliomee, D. “Gelling kinetics of agar vs gelatin.” Carbohydr. Polym. 305 (2023): 120558.
  • US FDA CFR §172.260 – Agar.
  • Cape Crystal Recipe Lab – Vegan Strawberry Mousse tutorial.

Written by Edmund McCormick, Food Technologist (20+ yrs).
Last reviewed: 18 June 2025

 

 

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