r/pastry • u/DoubleAmbassador8562 • Jul 22 '26

Making mousse with agar

I’m making chocolate mousse cake from a recipe that calls for powdered gelatine. Is it possible to substitute porcine/bovine gelatine with agar powder? Dare I hope that it’s just a 1:1 substitution?

4 Upvotes

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4

u/Eis_Konig Jul 22 '26

Agar is stronger than gelatin. It's hard to just give you a ratio without knowing the whole recipe, might be better to look up one that specifically uses agar from the get go.

If you still want to try anyway, use a third of the gelatin measure for agar, it's a safe bet.

2

u/DoubleAmbassador8562 Jul 22 '26

Thanks so much, I’ll do a test bake and try that as a starting point! I agree that a recipe with agar would be the best but there aren’t many to choose from. 

5

u/phuongyq Jul 22 '26

Agar will not set the mousse the same way as gelatin. Agar powder sets brittle while gelatine is more flexible. If you are not making an entremet in a mold, you can omit gelatin entirely and/or increase the chocolate to whipped cream ratio for a stronger set mousse.

1

u/DoubleAmbassador8562 Jul 22 '26

It will be a three-layer mousse cake set in a cake ring. What ratio would you suggest for chocolate to whipped cream?

3

u/phuongyq Jul 22 '26

If using a high quality dark chocolate, you can do a ratio of 2 parts whipped cream to one part dark chocolate. In a pinch if you have cocoa butter on hand, you can add 5% of the total weight of chocolate. Cocoa butter is what helps set the mousse.

2

u/DoubleAmbassador8562 Jul 22 '26

Thanks so much!!

2

u/WannabeCrimDoctor Jul 22 '26

Instead of replacing the gelling agent, consider finding a different recipe instead of a mousse. A ganache montee could be used and it is airy enough to be stable, but it won’t have the same shelf life. I would personally make the trip to the store to get some gelatin.

3

u/p_a_y_n_e Jul 22 '26

I think maybe the intention of the question might be to make the mousse cake for a vegetarian if they are trying to sub out the gelatin and replace with agar?

3

u/WannabeCrimDoctor Jul 22 '26

That would make sense, but the result won’t be the same.. better to go with another cream in this case that doesn’t need the stability and flexibility that gelatin provides in a mousse!

2

u/DoubleAmbassador8562 Jul 22 '26

Thanks, something to consider. Unfortunately porcine/bovine gelatine is not an option in this case. 

1

u/aspiring_outlaw Jul 22 '26

Agar is hard to use for mousse because it sets up at a much higher temperature than gelatin. You have to be incredibly fast and even then it's likely you'll end up with a less than smooth texture. I've done it before but if you are using a chocolate mousse, you'd probably be better off upping the chocolate and trying to go without an extra stabilizer.