Gelling doses

Gelatin, agar and carrageenan calculator

Paste the recipe. The ingredients on their own are enough. Savvy reads which gelling agent it uses and works out the published dose for it, and you can switch to another agent from there.

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What it is

How much of a gelling agent a liquid needs, and that this differs by agent.

Gelatin, agar and carrageenan each set a liquid at a different rate, published as a percentage of the liquid’s weight. A recipe that sets softly with 0.6% gelatin would set the same liquid with as little as 0.2% agar, because the two set by different means and neither dose transfers to the other without conversion.

Kappa and iota are both carrageenan, and dosed separately, because they set to different textures at different rates. Every figure Savvy gives here is a published one, with the publisher named beside it.

How it is worked out

The published rate, applied to the recipe’s own liquid weight.

Savvy adds up the weight of everything in the recipe except the gelling agent itself, and applies the published rate for the chosen agent — as a range, because the rate itself is published as one — to that total. Where two publishers give different ranges for the same agent, both are shown rather than averaged into one.

A worked example
  • 500 gdouble cream
  • 100 gwhole milk
  • 60 gcaster sugar
  • —gelatin, to dose

500 g + 100 g + 60 g = 660 g liquid, at 0.6% to 1.7% (Khymos, Texture v3.0 p. 27) = 4.0 g to 11.2 g gelatin

Where it goes wrong

Alcohol and certain fruits stop a gel from setting, and agents differ in which.

Gelatin is stopped by alcohol above about 40% of the finished mix, and by the proteases in fresh kiwi, papaya, pineapple, peach, mango, guava, fig and ginger — each of those fruits breaks down the protein gelatin depends on, and cooking the fruit first removes the effect. Agar tolerates all of it: salt, sugar, alcohol, acid and the same proteases pass through an agar gel without stopping it.

Carrageenan is not documented either way on this. The publisher that lists gelatin’s inhibitors and agar’s tolerances gives no protease or alcohol entry for kappa or iota carrageenan — iota’s only listed tolerance is salt, and kappa’s is blank. Savvy states that plainly rather than assuming carrageenan is unaffected.

What else to ask
What Savvy is

Every recipe you cook, in one place.

Savvy takes a recipe however it arrives — a link, a video, a photograph of a notebook page — and gives it back clean, weighed, and ready to scale. The numbers come out of the recipe, not out of a form.

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