Is it permissible to sell milk by weight (kilogram), based on the assumption that one liter of it weighs one kilogram, while ignoring the variation in its density?

Selling milk by weight for money is permissible, provided the weight is known. A measuring cup is not sufficient if the weights differ. A slight difference that does not lead to dispute is overlooked. It is permissible to sell what has been established by text as measurable by volume or weight, by weight or volume, for dirhams.