Sparkling water won't break your ice maker, but it'll make lousy ice

Sparkling water won’t damage a portable ice maker’s mechanism, but it makes worse ice and can cause a mess.

The machine doesn’t care what liquid you pour in—it just pumps water over a cold plate. CO2 doesn’t chemically attack anything inside. The risk isn’t mechanical; it’s practical. Carbonation causes foaming, which can confuse the water level sensor or let air into the pump line. That can lead to the machine running dry or overflowing. Also, the ice itself will be cloudy, fragile, and full of trapped air pockets, so it’ll melt fast and look weird in a drink.

If you want sparkling ice for a cocktail, you’re better off freezing it in a regular tray. For the countertop machine, stick with still water. Most portable ice makers are cheap enough that you’re not risking much, but there’s no upside.