I've always made GF free veggie mincemeat. I don't use any suet 'cos it's not nec. It's only so the stuff will come out of the jar. I just put a tabsp. or more if nec. of almond oil in it.
Also I put it on a very low heat to slowly cook it (it's a Delia recipe) and that stops it going off.Oh and I put a LOT more booze in it than she says
That also is for the keeping qualities of alcohol. It lasts forever really 