1. Place 3 tablespoons of water, or 3 tablespoons of the liquid that needs to be set, into a small heatproof bowl. Sprinkle the powdered gelatin over the liquid and stir until the gelatin is fully incorporated.
2. Place the bowl in a pan of barely simmering water. Leave until the gelatin has completely dissolved and turned transparent, approximately 5 minutes.
3. Test the gelatin by dipping a spoon into the liquid. If any undissolved granules stick to the spoon it needs a little longer. Don’t take the gelatin off the heat until all the granules have dissolved. Never let it come to the boil.
4. Strain the gelatin into the liquid that needs to be set.