This recipe takes about 20 to 30 minutes to freeze in an electric ice-cream maker.
Combine water and ginger in a small saucepan; bring to a boil. Drain. Combine ginger mixture, milk, and sugar in a medium saucepan. Scrape seeds from vanilla bean; add seeds and bean to milk mixture. Heat the milk mixture over medium-high heat to 180° or until tiny bubbles form around edge (do not boil). Remove from heat.
Place eggs in a large bowl. Gradually add hot milk mixture, stirring constantly with a whisk until blended. Let stand 15 minutes. Strain milk mixture through a sieve into pan; discard solids. Heat milk mixture over medium heat to 160°, stirring constantly with a whisk. Cool completely. Pour mixture into the freezer can of an ice-cream freezer, and freeze according to manufacturer's instructions.