As new barrels arrive at wineries, we have a set of instructions in pdf on how to prepare them for use: How To Use A New Barrel.
And we also have the following tips and suggestions for receipt, storage and use:
• Upon receipt of new barrels, they should be carefully unwrapped and inspected. If they will not be used for a month or longer, they should be wrapped again in plastic to minimize shrinkage and drying out of the wood.
• Ideally, you should store new barrels in a cool, moderately dry area—off the ground and with protection over the top of the barrels.
•The barrels should be stored head upright, on a pallet, plywood or heavy cardboard, with a piece of cardboard over the top to protect the head.
• At no time should the barrel be allowed to remain on a wet floor or in standing water. It is advisable to store in an enclosed space and out of the elements, as sun and wind will cause the barrels to shrink and rain will cause them to mildew.
Prior to Use:
• We advise filling the barrel with with approximately 20 liters cold water and allowing it to stand vertically for 12 hours on one head and then 12 hours on the other head. After the barrel is “tight,” empty the water out, rinse the barrel, and then turn it over and let it drain completely for an hour or so.
• Alternately, we recommend filling the barrel with 20 liters hot water, standing the barrel vertically on one head for two hours and then turning it over for two hours in the other direction. Following the same rinsing and draining procedures as above.
If after that time there are no visible leaks, the wood has swollen up and is ready to be used for wine.
The longer a barrel remains unused, the more the wood will shrink, and consequently, the longer it will need to soak up with water.