I just noticed why my iced americano that I made at work taste like something isn't really right

This one I made at home before I go to work and my coffee ground is mixed arabica and robusta,
While the one at work is 100% robusta and as I Sip my coffee and said "this one tastes better than the coffee at work." And my bro was like "Ofcourse, robusta isn't supposed to be for cold beverages." And yea I just remember that lol