Semi-refined is only preformed using Eucheuma Cottonii or Eucheuma Spinosum.  The raw weed is first sorted and crude contaminants are removed by hand.  The weed is then wash to remove salt and sand and then cooked in hot alkali to increase the gel strength.  The cooked weed is washed, dried and milled. Eucheuma Spinosum under goes a much milder cooking cycle as it dissolves quite readily.  This product is called Semi-refined Carrageenan.