Hi Jeremy, we re-burn large barrels for our local customers; we take off an end hoop, loosen the other hoops and remove one head then retighten the hoops. We scrape out the old char and then build a fire with white oak scraps and shovel the fire into the open barrel, rolling the barrel around until we get the char of choice. Then we reassemble the barrel. This can usually only be done once with a barrel that has a full thickness stave. We sometimes do it with smaller barrels too, but the 3 liter barrel is made with thinner wood. It’s too hard to make 1, 2 and 3 liter barrels with thick staves so by the time you re-burned a 3 liter the wood would be even thinner and the thin wood reacts more to climate changes, it will twist, warp and the staves will crack. However once the barrel becomes neutral (no longer imparts color and flavor) it is still a valuable tool. Wine, whiskey and other spirits can be left in a neutral barrel that doesn’t have a finish coat for several months or years, oxidation and evaporation can take place through the pores of the wood and the spirits will become thicker or more viscous with a more intense flavor. It must be stored in an area like a cellar with the proper temperature and humidity. If you cannot use a neutral barrel yourself check with some wine makers, they are always on the lookout for barrels in good condition that have become neutral. At your service Clay Johnston