So the juleglogg experiment worked out well. Just straight frozen berries filling 80% of a couple of half-litre mason jars filled up with 22 buck Polish vodka and left for three weeks in the cold room. Polish vodka is made of rye, not spuds or whatever else other folk make the vodka out of these says.
Not being a big consumer of spirits, this turned out more to my liking than I would have thought. The dry berry flavour is far better than a store-bought flavoured vodka, twiggy and unprocessed. The colour is deep as jam.