But.. that's what barrels are for ;) There are mods that can increase stack sizes if 10 barrels per stack is too few.
This mod may be relevant, you don't need empty barrels with fluids at all. Seems to be exactly what you were asking:
https://mods.factorio.com/mod/NoEmptyBarrels
Also Omnifluid replaces all fluids with solid items, though doesn't seem to be 0.18 yet. Maybe it's easy to convert?:
https://mods.factorio.com/mod/omnimatter_fluid
