Add cream, milk, and sugar to a saucepan over medium heat and stir until dissolved.
Split the vanilla bean lengthwise and scrape seeds into the liquid mixture. Add bean pod and heat until simmering (do not boil).
Whisk egg yolks until light and thickened.
Slowly pour one cup of the cream liquid into the yolks whilst whisking. Whisk the egg yolk mixture back to the saucepan.
Stir liquid over a medium heat for about 5 minutes until the custard coats the back of a spoon. Don't boil.
Transfer to an airtight container and refrigerate for at least 3 hours (preferably overnight).
Add beer to a saucepan and simmer until it reduces to roughly 3/4 cup then refrigerate until cooled.
Whisk beer into custard base and then add to ice cream maker. Churn as per manufacturer's instructions.
Once churned, add to an airtight container and freeze for at least 2 hours.
