Name: Agar -agar
Ingredients: 10 grams of peptone; 5 grams of coarse sea salt; agar (1 to 2 percent of the total liquid); sodium carbonate solution

Agar -agar

Ingredients

10 grams of peptone
5 grams of coarse sea salt
agar (1 to 2 percent of the total liquid)
sodium carbonate solution

Directions

Prepare meat juice as directed under 'Bouillon'.
Add 10 grams of peptone and 5 grams of coarse sea salt to the meat juice.
Cut agar into small pieces and wash thoroughly.
Place the mixture in an autoclave and heat to 240°F (115°C) for 10 minutes.
Lower the pressure and filter the fluid through Novy's agar apparatus, making it slightly alkaline with sodium carbonate solution.
Fill flasks, tubes, and Petri dishes with the hot agar.
Sterilize in the autoclave at 240°F (115°C) for 35 minutes.
Allow agar to cool to 102°F (39°C) before it solidifies.

Recipe from a historical cookbook (Internet Archive).

Transcribed from a scanned cookbook and modernised for today's kitchens. Where the book gave no heat or time, or said "a moderate oven", the temperatures and times here may be modern equivalents rather than the book's own figures.