Alcohol Question

[Reverend Joe]

And by the way, I'm fairly sure liqueur keeps indefinitely. Unlike wines, liqueur is very alcoholic, so none of its ingredients should spoil.

Edit -- just found this:

Liqueurs and Cordials:
The shelf lives of liqueurs are more temperamental than the base spirits because they contain sugar and other ingredients which can spoil, some more than others. Most opened (and well sealed) liqueurs should last for months and even years depending on their alcohol content and preservatives. Again, opened bottles are likely to lose some of their characteristics due to exposure to air. Once you begin to see any sugar crystallizing on the bottom, discoloration, curdling or other changes you will want to throw that bottle away or at least give it a taste test before mixing with it.

So, it might be all right, but I would stick to the smallest bottle you can get in case it doesn't age well.