This article is from the WineMaking FAQ, by malak@CAM.ORG (Don Buchan) with numerous contributions by others.
Usually empty unused barrels can be stored indefinitely. Once filled
with wine, the barrels must either be always full or specially treated
when emptied. The recipe for storing solution (for a 180 litre; 40
imp.gal; 50-60 USG) is about 100g (1/4 lb) citric acid crystals, 100g
(1/4 lb) sodium or potassium metabisulphite and enough water to fill
the barrel. Then bung it tight.
Considering the possible loss of tannin by leaching to the above
conditioner, others do the following with their barrels when empty:
- wash out the barrel thoroughly
- let it dry for one week without bung stopper
- burn a sulphur stick in barrel with stopper applied
This should take care of the barrel for one year. There is a
possibility that the staves will warp using this method, so be careful.
You should also refill with storage solution several weeks before
A new barrel should be filled with water for a week or so before
filling with wine as a new barrel will often leak. For leaks there are
three things to do:
A) wait a few days. Swelling will stop a lot of leaks.
B) if it still leaks between staves, pound the hoops towards the middle
of the barrel to tighten the pressure.
C) if your leak is from a defect in the wood such as a small hole,
whittle a small plug out of a piece of oak and jam it into the hole.
Bleach and other cleaners not specifically labelled for wood barrel
cleaning shouldn't be used to clean your barrel as it could remain in
the wood and affect the wine you put in it. If the barrel is dirty,
then scrub it with water. One trick is to drop a length of chain inside
and shake the barrel around.
Don't reuse a barrel in which wine has turned to vinegar; it's
impossible to get rid of the vinegar bacteria from the wood. Use the
barrel as a planter in your yard.
It's generally not a good idea to mix wine types in a barrel, or white
and red wine. You'll taste the previous wine in the subsequent wine.
Barrels need regular topping off with wine to keep them full. Since a
barrel is porous, wine evaporates through the wood. Once a week for
topping off works fine; some wineries top off twice a week. Keeping the
humidity up in your winery cuts evaporative loss. Losing half a litre a
month is normal.
The stave with the hole in it ("bung stave") often cracks just at the
hole as this is the weakest part of the barrel. Either replace the
stave or seal the crack with melted wax.
Wipe the area around the bung hole often with a sulphite solution. This
is the area that gets seepage and spills, and the sulphite keeps this
area from being a source of spoilage.
Five gallon barrels are discouraged because of the high surface to
volume ratio. The wine can get too oaky relatively quickly. When using
a five gallon barrel, keep the wine in for a shorter period of time,
then blend it with wine from the same vintage that was not in the
barrel; the key is to not let it sit too long.