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How to Harvest Algae for Agar

Agar is an extract of red algae that is used as a thickener for food, a clarifying agent for brewing beer, and a laxative. It also is used by vegetarians as a substitute for gelatin in confectionery. It is commonly used in the Far East, and most of it is harvested in Portugal, Russia, New Zealand and India. Agar is usually suitable for strong-flavored dishes as it has a discernible taste.

Things You'll Need

Nets
Diving suit
Container for pulled algae
Pond or estuary

Instructions

- 1
  Cast a net into the sea to collect the seaweed. The algae can be located up to 20 meters deep, usually in partially shady locations and where the temperature is at least 68 degrees C for three months of the year. Alternatively you can dive into the sea and pull the algae off rocks by hand, storing it in a container.
- 2
  Place the algae into a pond or estuary with sand and water for it to grow, or "culture." The algae will grow, but strong winds will push it aside, so make sure it is slightly sheltered.
- 3
  Change the water once every three days.
- 4
  Collect half the algae every 35 to 45 days.
- 5
  Leave the collected algae to dry in the sun for two or three days. After it is dried, it can be turned into agar by boiling it and using the liquid that results. The liquid starts to form a gel when it reaches 90 to 104 degrees F.

Rocks & Minerals