
Tangerine is a small, deep-orange mandarin with a thin, loose rind and sweet segmented flesh.
Any other mandarin swaps in with little adjustment, though they are not interchangeable by taste — clementine runs sweeter, so taste before you build. Anything sharper needs sugar to compensate. When none of them is at hand, orange juice with a squeeze of lemon rebuilds it closely enough.
Mandarin, clementine, satsuma
Mandarin is the family name, and the group is not one species: modern mandarins are Citrus reticulata crossed and re-crossed with pummelo, clementine is a mandarin × sweet orange hybrid; satsuma is Citrus unshiu again. Any of them works in a drink. Clementine is usually seedless, but only when grown away from other varieties — near a pollinator it comes out very seedy indeed.
Orange
More acid, less perfume, and a thicker pith. Going from tangerine to orange means adding sugar or accepting a sharper drink; going the other way means adding lemon to replace the acid you have just given up.
Up to about four weeks at 5–8 °C. That is the catch: a domestic fridge runs near 4 °C, below the point where mandarins take chilling injury, so the coldest shelf will shorten their life rather than extend it. Squeeze to order — tangerine juice turns bitter within hours as limonin develops, which is a different problem from freshness fading.