Officially, just pure water. Unofficially, you can hack it [1]. Back in 2015, there were plans to unveil something that could officially do more [2], but that

Officially, just pure water. Unofficially, you can hack it [1]. Back in 2015, there were plans to unveil something that could officially do more [2], but that seems to not be for the consumer market. 1. https://www.nytimes.com/2013/02/27/dining/hacking-home-soda-making-machines.html https://www.nytimes.com/2013/02/27/dining/hacking-home-soda-... 2. https://firstwefeast.com/eat/2015/04/sodastream-mix-will-carbonate-any-and-all-liquids-including-alcohol https://firstwefeast.com/eat/2015/04/sodastream-mix-will-car...