Archive for October 5, 2010

Molecular Gastronomy – Agar agar

October 5, 2010 1 comment

Molecular gastronomy is back and ready to dish out more advanced and novice molecular based gourmet recipes. I want to start with a primer of sorts: something to introduce the topic of discourse before we start to deconstruct. For this post we will be focusing on the hydrocolloid: Agar.

Agar: a brief description

A linear polysaccharide made of glaactose units. Agar is a red seaweed and its function is for Gelling (but I will show you a recipe for “cold-oil spherification.”

Agar is very similar to carrageenan but lacks the sulfate groups found in carrageenans. Agar is very adaptable to high heat and is often served hot and allowed to gel while cooling. To use agar in “cold-oil spherification” drop liquid agar at a temperature of roughly 45-50C into a bath of cold oil.

How to use: Disperse in a cold liquid and heat while stirring until completely dissolved. The target temperature for this to occur is about 90C or above.

You will expect to use about .5% to 1% in your recipes

To make a fluid gel: Make an agar gel in the range of .6%-1.2% and shred in blender until a smooth consistency is reached. You could thin out the gel by adding more liquid or you could thicken the mixture by adding some xantham gum. Could be served hot (but never to boiling).

Gel type: thermo-reversible: Thermo reversible gels melt when heated to a high enough temperature. Texture: firm, strong, and brittle. Gel Temperature: Approx 35C. Setting: Very Fast. PH tolerance: very good except for the fact that keeping acidic solutions heated for a long time will cause the agar to break down. Freezer stable: No. Flavor Release:Good.

Note: you could solve the issue of keeping acidic solutions hot, and thereby causing your agar to weep, by adding some more ascorbic acid to your solution to balance things out.


Blackcurrant and ginger fluid gel sauce


100g Simple Syrup

500g Blackcurrant puree (I use The Perfect Puree from Napa Valley)

30g ginger juice

pinch of salt

6.3g of Texturas brand Agar(.8%)


Blender, Scale


1: Add simple syrup to the blackberry puree until you reach a desired sweetness

2: Add ginger juice

3: Add salt

4: Weight blackcurrant mixture and place in a pan with .8% by weight agar. So if total is 780g, use .8% of 680g which will give you approx 6.34g

5: Bring mix to a boil, then reduce heat and let simmer for 2min. Lower heat and stir to dissolve the agar.

6: When agar is fully dissolved, pour into plate to chill.

7: Take the chilled gel and place it in the blender. Blend until smooth.

That’s it for now. Feel free to ask me questions. Stay tuned for more molecular gastronomy!!!