Here at LusoBarrel around 50% of our business is supplying used barrels (mainly used Port, Madeira and Sherry barrels), but a few others too). If you go online, you may find all kinds of advice about what you need to do before filling used barrels (leak testing them, cleaning them out, steaming them, treating them with sulfur, letting them sit with clean water for a day and so on), but are these steps really necessary?
The answer is sometimes they are necessary, but it really depends on where you are sourcing the barrels from. If you are buying the barrels direct from the vineyard or distillery that originally used them, then you really have to be a bit careful – the barrels may have broken staves or other damage, they may have been sitting around unused and/or empty for a while and they may have been stored in inappropriate conditions. If you are buying from an agent, then you may have to consider all these issues as well as the genuine provenance of them.
However, if you are buying your barrels from an established cooperage that is used to handling used barrels, then the truth is you have to do pretty much nothing prior to filling. In our case, all of our used fortified wine barrels are delivered with a few litres of the original liquid in them, so all you have to do prior to filling is to pour this liquid out (it is safe to drink, so no need to waste it!) and then fill. You do not even have to rinse the barrel.
The reason that you do not need to take any other steps when you buy used barrels from a reputable cooperage is that they will have done all the other steps for you: every used barrel that passes through our cooperage is visually inspected for damage (when any broken staves or hoops will be replaced), then pressure tested for leaks. They will never be allowed to sit empty or to dry out and by keeping a few litres of fortified wine inside them, bacteria or mould will not be able to grow as the alcohol level is too high (so we never use sulfur for example). Then by rolling them periodically, we make sure that none of the wood dries out (which can cause the wood to shrink to cause leaks). Sometimes clients will also ask us to tidy up barrels, by giving them a sand to clean up the surface, adding a logo on the lid, changing the hoops or whatever. Finally, it goes without saying that we will always keep barrels in a cool, dry environment to further protect them.
A lot of the work that we do in the cooperage is receiving bulk quantities of barrels and processing them one-by-one so that we can be completely confident that they are all ready for filling. So the answer to the question of how to prepare your barrels for filling really depends on where you bought them from, as a decent cooperage will have taken all the risk, labour and guesswork out of the process!
