The first thing to say is that all the barrels that leave our cooperage (new or used) are pressure tested before they leave the premises. This means that we put water in them and let them sit for a while (and turn them) and check to see if there are any leaks. So when they leave our facility we know that they are fine, but occasionally they will arrive at a client’s premises and they will have a small leak. So what should you do then?
A leak can occur for a few reasons – if the barrel has been poorly made (so for example the rings have not been applied with sufficient pressure) then the barrel needs to be returned to the cooper. This should never be the case with a decent cooperage however, particularly if all the barrels have been pressure tested and the barrels have been made using a hydraulic hoop press (see the image below) to make sure that the hoops have been applied with sufficient pressure.
One more likely possibility is that a stave has cracked in transport – this should not happen of course and we do everything we can to prevent this from happening, by giving the barrels protection for transport and making sure they cannot move in the container or pallet. However in exceptional circumstances they can be damaged (typically by clumbsy handling). If a stave is cracked, then the stave will need replacing to guarantee no leaks, so there is really no way round this.
When there is a leak, by far the most likely cause is the wood drying out. We always ship our used barrels with some of the original liquid (e.g. Port wine or Madeira wine) inside to make sure that they do not dry out and maintain their original characteristics, but even like this there is a chance that there will be some drying, particularly on long journeys to the other side of the planet. As the wood drys, it shrinks and tiny gaps can open up between the staves. The solution is simple however! Once the barrel is filled, the wood will rehydrate and expand to close the gap and the barrel will seal itself.
The most common place for these leaks to occur is between the head and the staves, so generally you should turn the barrel upside down so that the leak is at the bottom, add water and leave it overnight. By the next day, the leak should have stopped. You should generally avoid leaving water sitting around in barrels for too long however, as you do not want the water to get stagnant.
When we supply used barrels, as well as pressure testing them, as well as substituting damaged staves (using staves that have been cannibalised from barrels in the same lot) we also replace hoops where appropriate and carry out any other repairs that may be necessary. Generally we will also tidy up the surface with a quick sanding if the wood has seen better days. This means that we can offer used barrels with the same guarantee of quality as new barrels. Here you can see us removing the hoops from a used Port barrel to be replaced:
You will see other options online about using wax or straw to seal leaks or even tightening the hoops, but this should not be necessary if the barrels have been correctly coopered and/or restored. If you buy used barrels that have not passed through the hands of a decent cooperage, then of course you are much more likely to encounter serious problems with the barrels that acquire, so unless you have a cooper on site, then this is generally a risky option. We take enormous pride in the quality of barrels that leave our facility whether used barrels or new barrels, so we like to know from our customers if there have been any issues and we will always be available to advise on how best to resolve the situation!
