Initially I tried to transfer some vinegar from one barrel directly into a other empty barrel, which did not do anything.
Then I tried to transfer some vinegar with a bucket. But the empty barrel still refused to take it.
Then I emptied the barrel with vinegar, and tried to refill with the same vinegar (now in buckets) ... and this barrel now also refused to take the vinegar ... now that's definitely something that should not happen.
... I live in Brodgar. So building new barrels ... is kinda expensive (lack of near tree's and all.
)+ Just in case I checked with default(online) client. Nope,those empty barrels still refusing to swallow [strike]new stuff[/strike] vinegar.
+ Erm. Dropping some water from a cauldron in those empty barrels still works. Which suggest it might be intentional. As in Demijohn designated as only container that might be used to drop vinegar in. (don't like)
(Note: you can of course still drop vinegar in a barrel that still contains some vinegar.)
