Agar-agar acts as a gelatin, but is also used as an emulsifier, thickener and stabilizer in many commercial products such as ice cream and soups. It can also be used to clarify wine and beer.
It is preferred by vegetarians to gelatin which is made from animals.
It is made from red and purple seaweed. The seaweed is harvested, dried and blanched, then boiled in water. The seaweed is then strained out of the water and discarded, and the water evaporated down to leave the powder. Other methods freeze dry and dehydrate the seaweed, then grind it. You can buy the resultant powder in flake, bar or powder form.
Agar-agar works by absorbing and retaining moisture molecules. It has one significant advantage over gelatin, which is that it will stay set at room temperatures, unlike gelatin which eventually melts.
Cooking Tips
Substitute agar-agar on a one-for-one basis with gelatin. If you are using a bar of agar-agar, rinse first in cold water, and break into small pieces. Simmer agar-agar in whatever form you are using it in water or other liquid for a while to get it to dissolve.
Do not use in combination with vinegar, rhubarb, spinach or chocolate, as it will not set. One bar of agar-agar will set two cups (500 ml) of liquid.
Substitutes
Gelatin
 |
|
Amount
|
| Calories | |
1.5
|
| Fat | |
0 g
|
| Saturated | |
0 g
|
| Trans | |
0 g
|
| Cholesterol | |
0 mg
|
| Carbohydrate | |
.35 g
|
| Fibre | |
.05 g
|
| Sugars | |
0 g
|
| Protein | |
.05 g
|
| Potassium | |
11.3 mg
|
Nutrition facts source: USDA http://ndb.nal.usda.gov/ndb/foods/show/3304?manu=&fgcd=
Equivalents
One bar of agar-agar = 4 tablespoons flakes = 2 teaspoons powder
1 tablespoon = 5 g
Literature & Lore
The name agar-agar is Malaysian. It has been produced there for many centuries.
“Meanwhile in Asia, there’s a thousand year tradition of using seaweeds, seaweeds like agar for making a gel. Calling it agar sounds unusual. We say, oh, god, I don’t want that non-natural thing. But let me tell you, it’s just as natural as gelatin or essentially anything else you do.” — Nathan Myhrvold. Modernist Thickeners. In: HarvardX SPU27.2x. Science & Cooking: From Haute Cuisine to Soft Matter Science (physics). Module 2 – Viscosity and Polymers. Accessed November 2022 at https://learning.edx.org/course/course-v1:HarvardX+SPU27.2x+1T2022/