By simply substituting the referent of the pronoun the clause becomes ὅταν τὸ γένημα τῆς ἀμπέλου πίνω καινὸν ἐν τῇ βασιλείᾳ τοῦ θεοῦ. The phrase οἶνος νέος is mentioned in Matthew 9:17 (bis), Matthew 26:29 (after explicating the pronominal referent), Mark 2:22, Mark 2:22 (bis), Mark 14:25 (after explicating the pronominal referent) and Luke 5:38).Κατὰ Μάρκον 14:25 wrote:Ἀμὴν λέγω ὑμῖν ὅτι οὐκέτι οὐ μὴ πίω ἐκ τοῦ γενήματος τῆς ἀμπέλου, ἕως τῆς ἡμέρας ἐκείνης ὅταν αὐτὸ πίνω καινὸν ἐν τῇ βασιλείᾳ τοῦ θεοῦ.
Explicating the referent of the pronoun doesn't greatly help me understanding the role of the καινόν though. Perhaps it is "I will drink this, the thing that has been produced from the vine (that we are drinking), and that will be new wine in the Kingdom of God".
Reading that, my knowledge of syntax / word-order is tested to failure (Is that more Victorian era grandiloquence on my part, Carl?), and I am left asking question like;
- Is it regular usage to put the adjective used with that type of verb into that position?
- If not, is it emphatic?
- If not, is it adverbial?
- Is there interference from another language at work?