Agar is a vegetarian gelling agent derived from dried seaweed. Although some agar is wild harvested, it is more commonly farmed commercially. Like gelatine, agar is thermo-reversible but at much higher temperatures, and it has around 5 times the setting properties – so much less is needed. Unlike gelatine, agar sets at room temperature but will hold its shape when hot.
It forms a ‘framework’ that holds liquid molecules in place. A 1.5% solution of agar forms a gel on cooling to room temperature that does not melt below 85º C. This is a novel property of agar that finds many uses in food applications. The gel strength of the agar is influenced by concentration, time, pH, and sugar content. The pH noticeably affects the strength of the agar gel; as the pH decreases, the gel strength weakens. Sugar content has also a considerable effect over agar gel. Increasing levels of sugar makes gels with a harder, more yielding texture.
To use mix the agar with the liquid to be gelled and bring to the boil, whisking all the time till completely dissolved. Remove from the heat and allow to cool. It will remain a liquid until it cools to 35º C at which point it will begin to gel. The gel will remain solid until it is heated again to 85º C.
Agar Agar Spaghetti, also called molecular spaghetti or flavored spaghetti, is another creation of molecular gastronomy Chef Ferran Adria and El Bulli team. It consists of a spaghetto or noddle usually about 3 mm to 5 mm thick and 2 m long made of a flavored liquid jellified with agar agar (agar agar gelification). The agar agar spaghetti can be served cold or hot.
The spaghetti are created by injecting the hot flavored liquid with agar agar into a PVC or silicon tube using a syringe or the adaptor for the ISI Whip which connects it to a PVC tube and removes the spaghetto using nitrous oxide.
1. Place some ice and cold water in a bowl.
2. In a pan place the liquid that you want to jellify.
3. Add the Agar Agar with a concentration of 1.6%.
4. Bring it to the boil, stirring constantly with a beater.
5. Take off the heat and skim to eliminate any impurities.
6. Fill the syringe with the preparation and connect the rolled tube to it.
7. Disconnect the tube from the syringe and place the tube in the iced water. Let it rest for 1 or 2 minutes.
8. Fill the syringe with air and connect it again with the tube. Press on the syringe pump and expel the spaghetti out of the tube. When possible expel directly onto the serving dish. Repeat as many times as tubes you have or required spaghetti.