The Real Reason Chocolate Chips Don't Melt In The Oven
While chocolate chips are the sole reason why chocolate chip cookies are even a thing — and a delicious thing at that — it is hard not to wonder why chocolate chips don't melt. Take a regular bar of chopped chocolate, mix it into a brownie batter and you'll have silky, dark brown chocolate oozing out of the brownies. But no matter how high the temperature of the oven, chocolate chip cookies almost always come out peppered with still solid chunks of chocolate chips. As with all things baking, there is logic to this mystery too.
Powders and nibs aside, chocolates are usually found in two forms, each with different uses: as bars and as chips. While eating chocolate and baking chocolate are different, Our Everyday Life says that when you're trying to melt some chocolate, it's best to leave the job to chocolate bars, preferably baking chocolate bars at that. Chocolate chips, which The Pioneer Woman says are generally made from semisweet chocolate with at least 30% cocoa, are meant to hold their shape when baking, so you won't see them melting in your chocolate chip cookies.
Chocolate chips are designed to hold their shape
Where couverture chocolate has a high amount of cocoa butter which makes it so sought after in professional kitchens for its smooth and glossy melt despite the hefty price tag (via The Pioneer Woman), chocolate chips have a very low percentage of cocoa butter. This is why, says Mental Floss, chocolate chips give more resistance to the heat of an oven.
Additionally, these chips also often come with stabilizers and emulsifiers which are both meant to help chocolate chips keep their shape. So, the chocolate chips that you're trying to melt in the oven are pretty much designed to do the very opposite! While you could melt chocolate chips in a microwave or by using a double boiler, it is likely to be more thick and tough than the smooth liquid that you want the chocolate to be.
In fact, Epicurious even makes a case for why you shouldn't be using chocolate chips in your cookies, precisely because they don't melt in the oven. Instead, they suggest chopping up a chocolate bar and stirring the pieces into your dough, because who wouldn't like a cookie with actual puddles of melted chocolate in it?