Seaweeds must be harvested from the sea very early in the morning or while the tide is still low.
Procedure:
1. Wash the seaweeds very well, drain and dry (Spread over a wire or bamboo screen for the purpose) for a week.
2. To remove the fishy odor and taste, soak and dry the seaweeds in fresh water for 5-10 minutes, and dry again in the sun until it becomes dirty yellow in color.
3. Bleach in 1 liter of water with 1 tbsp. vinegar until it turns olive green in color.
4. Put again in the sun until it turns light brown. To extract agar:
5. Put 1 kilo dried seaweeds in 1 liter water with 1 tbsp. Vinegar (or more effective, in 3½ liter water, 80 ml. 0.1 N sulfuric acid (H2SO4)
6. Boil and constantly stir for 1 hour.
7. Strain in muslin cloth while hot.
8. Allow to cool in room temperature for 5 hours.
9. When it has hardened, slice into desired sizes.
10. Put in ice sprinkled with salt for 2-3 days, or in a freezer overnight.
11. Next day, thaw the frozen seaweeds and allow to dry.
12. Put again in the sun until the desired fineness is attained.
13. When it cools, it is then ready to cook or bring to market.
Source: PCARRD Monitor August 1987