Hilchos Issurei Mizbeiach 6:9

The following types of wine are unfit for libations on the altar: sweetened wine, smoked wine, and wine cooked on a fire or in the sun until its taste is altered. Regarding wine that was warmed in the sun but whose taste wasn’t altered, plus raisin wine, wine from the vat newer than forty days old, wine from grapes that were grown on a trellis, wine from a vineyard in an arid plain or in a trash heap, wine from vines that had other produce planted between them, and wine from an unworked vineyard – these shouldn’t be brought as libations, but if they were brought, they are accepted.

Hilchos Issurei Mizbeiach 6:10

If wine was left uncovered [so that a snake might have gotten into it], it is not fit for the altar. If a vine was draped over a fig tree, the resulting wine is unfit for libations because its aroma is changed. Leviticus 23:37 says, “sacrifice and libations” – just like an offering must be unchanged, the libations must likewise be unchanged.