A.T. Robertson Commentary Matthew 9:17

"Neither do [men] put new wine into old wine-skins: else the skins burst, and the wine is spilled, and the skins perish: but they put new wine into fresh wine-skins, and both are preserved." — Matthew 9:17 (ASV)

Old wineskins (ασκους παλαιους). Not glass " bottles " but wineskins used as bottles as is true in Palestine yet, goatskins with the rough part inside. "Our word bottle originally carried the true meaning, being a bottle of leather. In Spanish bota means a leather bottle, a boot, and a butt. In Spain wine is still brought to market in pig-skins " (Vincent). The new wine will ferment and crack the dried-up old skins.

The wine is spilled (εκχειτα), poured out.