Not that a formula for making soda can be ‘open sourced’, but just in case you have a spare weekend or three…

How to make your own cola that tastes similar to commercial products.

Notes

• Make sure you get gum arabic from a food store, not an art store. Art store gum arabic is cheaper for a reason, it shouldn’t be eaten.
• Neroli oil is very very expensive.
• 75% phosphoric acid is some really corrosive stuff. Don’t think so? Watch hot dogs dissolve in it.
• And for the love of mike, don’t even bother with caffeine.

Or, you can just pay your $1.29 at the checkout counter of the grocery store.