In a medium bowl, toss to combine the Emmenthal, Gruyere, cornstarch, salt, garlic powder and white pepper; set aside.
Bring the wine to a simmer in a medium saucepan over medium-high heat. Add a large handful of the cheese mixture and whisk until smooth. Repeat until all the cheese has been added and is completely melted and smooth. Whisk in the applejack to taste.
Transfer the melted cheese to a fondue pot or casserole dish and serve warm (over a flame) with bread cubes, sausages, vegetables and fruit.