This SodaStream trick takes advantage of the fact Coca Cola, Pepsi, and others all make and distribute their own syrups, usually to pubs, bars, and restaurants. These are mixed on-site with carbonated water and served to customers through the soda guns you may have seen behind the bar.
This may sound familiar, mixing syrup with carbonated water, because it’s exactly the same process as mixing Sodastream’s carbonated water with SodaSteam’s sparkling water flavours (which are syrups).
Can you save money doing this? Yes, though maybe not as much as you might imagine, but sustainability-wise you are obviously saving a lot of packaging. I worked out that it costs 45p to make a cans worth of coke (330ml), or 66p to make a bottles worth (500ml). Based purely on the cost of the syrup.
Im a big fan of Coke Zero though you can do this with Coca Cola, Diet Coke, or any other syrup you can get hold of. Luckily I had a friend who helped me get hold of a syrup box, but you can purchase the same online through a simple google search, on Amazon, eBay, or your local drink wholesalers. The syrup is known as ‘postmix syrup’ and comes in a package called a ‘Bag in Box’ (BIB).
Once you’ve got a BIB you’ll notice there isn’t a built in tap or easy way to get the syrup out so you’ll need to get hold of a Coca Cola BIB connector. Make sure you get the right connector for the brand of syrup you have, I understand Pepsi and others use different connectors. These are easy to find on Amazon and eBay, I paid less than 10 pounds on eBay, watch out for the online sites trying to sell these for extortionate prices.
There are different options next depending on how you want to dispense the syrup. I personally attached a tap to the end of the connector so I can periodically fill up a smaller and easier to manage dispenser.
Again I found all the parts required on eBay, a 3/8" hose to fit the coca cola barb connector and a tap with a barb fitting for the other end of the hose. I also fitted some hose clips to keep everything in place, though I’m not sure this was completely necessary!
Finally you want to mix your syrup with carbonated water from your SodaStream. I imagine this varies depending on the brand of syrup, Coca Cola advises to mix 5 parts carbonated water to 1 part of syrup. Therefore to make 500ml, mix 83ml (500 divided by 6) of syrup with the remainder carbonated water. To make 330ml, mix 55ml (330ml divided by 6) of syrup with the rest carbonated water.
It can be tricky to get the right amount of syrup but over time you’ll get used to how much is needed for the glass or bottle you’re using. You could even use a coffee syrup bottle and pump which dispense 10ml each time. Let me know your tips and tricks here! I use a dispenser I found on Amazon:
I found that it’s best to carbonate your water more than you would normally, to make up for the syrup which isn’t carbonated at all.
Simply mix your water and syrup together and there you have it.. your own home-made coca cola!
Good luck and let me know how you got on.
Also linked in a Reddit forum post