Peel, then squish your garlic clove. Rub the squished garlic around the inside of the inner pot to lightly flavour it, then discard.
Pour the ale into the pot, select Sauté and set the time to 15 minutes. Heat the ale until warm.
Place the cornflower into a bowl, along with the lemon juice and just enough additional water to loosen the cornflower to the consistency of double cream.
Pour the cornflower mixture into the warm ale, while whisking constantly. Cook until the ale mixture thickens.
Change the Saute temperature to low, then add the cheese into the thickened ale mixture a handful at a time. Mix well between each addition until the cheese is fully melted and repeat until all the cheese is added.
Season the fondue with a pinch of pepper and nutmeg, then press Cancel.
Select Keep Warm to keep your fondue gooey and melty whilst serving.
Serve the fondue straight out of the Instant Pot alongside accompaniments of choice.