late to the party...
A lot of this depends on the game world and how you care to handle potions. THere is nothing wrong with how you want to run it, just be ready for your players to quickly find ways around it or find ways to use it to their advantage.
in my homebrew potions have fairly set formulas, so 90% of all potions look, smell, and taste like a potion of their type. If you have learned that light blue liquids with a slight sweet smell are minor healing potions or that light brown creams with a nutty smell are salves of defense, then you will likely be able to identify them at any time there after. There are a few rare, or seldom used, recipes that create potions of a certain type in another form. These account for the other 10% of all potions, and allow me to be to throw a curve ball at my players now and then.
in a normal D&D game, I assume that characters either mark their potions once they have been identified or have some elaborate sorting routine (i.e. cure minor potions in left hip pouch, bull's strength on the right, and everything else clearly marked and in the backpack), or they make use of a magical storage device (like the haversack) that allows them to reach in and pull out exactly what they want without error.
I just had a real good laugh! 
