Hi dolly, don't know about the shop bought goose fat ( does it contain additives?) anyway, had goose for the 1st time a couple of christmases ago, collected the fat - goose produces a LOT of fat! used it for roast spuds and they were heavenly! kept the fat in a container in the fridge, and re-used it for couple of months, straining out any bits each time, until it had all gradually been absorbed by the spuds, we mourned the day when we used the last bit for a sunday roast! i'm sure health & safety would have a field day with that but hey, we all lived! (and i did the same last year)