Agar Agar Fine Powder - 100% Natural Food Grade What is Agar Powder? Agar is produced naturally from boiling particular types of carbohydrate in red algae where it forms the structural support for the cell walls. Our Agar powder is 100% Pure Food Grade which makes a great basis for making Agar Jelly for desserts or any type of nutrient Agar for growing bacteria and other microbiology studies. How to Use Agar Normal Agar Jelly. To make jelly, add approximately 15g of Agar Powder to 125ml of water; then boil the solution for 1-5 mins and leave to cool. The jelly should set within a couple of hours. Nutrient Agar Jelly (Luria Bertani Agar). To make Luria Bertani jelly, you will need 10g of Tryptone, 5g of Yeast Extract, 10g of NaCl (Salt) and 1 litre of distilled or deionized water.