Like many fats, dripping will turn rancid if it is kept for too long. If you collect the dripping fat from a roast, pour it into a suitable glass or china container; do not use plastic. Allow it to cool, then cover and put it into a refrigerator. Fresh dripping may be kept in the refrigerator for up to two weeks and may be frozen for up to six months.
Do not add the dripping taken from one roast to that from another. It will spoil the taste. Pour the second lot into a clean container, label it and store as before: this prevents any cross contamination and lets you keep track of how old the dripping is so there is less danger of keeping it for too long.