I have recently came across the Brewkeeper prestige class and I fell in love with it. The interactions it has with spells and potions is amazing for late game, especially when you have potions left over from lower levels; but one thing bothers me.
I know metamagic increases the level of the spell being cast but with brewkeeper you can add a metamagic effect onto a spell as you cast it. Cleric cast using prepared spells, so I want to know what happens when you add a metamagic effect onto it with the brewkeeper's helpful homebrew ability:
Helpful Homebrew (Su): At 2nd level and every 2 class levels thereafter, a brewkeeper can select one metamagic feat from the list in the following paragraph. She can spend points from her brew reservoir as a swift action to add a metamagic effect to a spell as she casts it, an extract as she drinks it, or a draught as she creates it. She does not need to meet the feat’s prerequisites in order to select the effect. Using this ability costs a number of brew points equal to the metamagic feat’s level increase (minimum 1).
Does it use up a spell slot of a higher level? If so, wouldn't that break the aspect of clerics needing to prepare the spell beforehand? For instance, if you prepare a use of a level 2 spell and augment it to level 3 with Helpful Homebrew metamagic, would that result in using a 3rd level spell slot while keeping all your level 2 spell slots free to take other spells?