They do not have to be hot, but it is a kind of latte if they are. Personally I like it cold. I put the cold water in a jug add the vanilla shake mix and a big teaspoon of instant coffee. Whisk with an electric blender until smooth. Then I add 3/4 ice cubes and whisk again to crushh the ice - its yum!! Enjoy
I have mine hot too. I mix bout 100ml of cold water n 300ml boiling water, then add a generous spoonful of coffee then add the vanilla sachet and get SHAKING!!! LUSH!
I do both the hot vanilla with coffee and the cold.
Have you tried it with cinnamon and sweeteners?
It's lovely hot, I used to have it for breakfast as a change from doing it like a latte.