I have recently bought four 6-gal PET carboys. They are very nice quality and the price was right and on sale at homebrewing.org However, I think they are better for primary fermenting and not for bulk aging. With 6-gal in the carboy, I found it took a full 1.5L bottle of wine to top it off plus about another 1-2 cups of water. The level now is just slightly below the neck of the carboy.
Is this just a PET carboy problem? What volume do you experts normally add to a glass carboy for topping up?
Is this just a PET carboy problem? What volume do you experts normally add to a glass carboy for topping up?