Oak Barrel Care
Welcome to the next level of winemaking - oak barrels. Oak changes your wine in two ways - the oak adds flavours and aromas to the wines. Largely this comes from tannins, polyphenols and vanillins present in all oaks, but different oak species, where it was grown, as well as how the barrel was treated (toasting) will add trace elements individual to that barrel. Secondly, oak is porous and there is slow oxidation that occurs maturing the wine.
Smaller barrels provide a much higher oak surface area to wine ratio and a great deal more oak character than a large barrel. Because of this flavour change will occur more rapidly and requires closer monitoring to ensure the wine does not become over oaked.
Tightening your new barrel
It is very important to make sure your barrel is tight (i.e. has no leaks). Fill the barrel with cool water and allow it to soak until the wood swells tight. Change the water every three days to prevent contamination of the barrel. When water no longer seeps out between the staves, or at either end, the barrel is completely tight. This can take two weeks or more.
Conditioning your barrel
To avoid over oaking you may wish to condition your barrel after you are sure it’s tight. Soak the barrel in very hot water for about a week, changing the water every two days. Each time you change the water, you should check to see how much of the raw oak flavour has been extracted: taste the water and look at its colour (more yellow = more oak). When there is little oak flavour and the colour is very pale, the barrel is ready for soaking with an acidic sanitizing solution.
Sanitizing your barrel
Use this procedure to sanitize your barrel before filling it with wine.
1. Fill barrel half-way with cold water.
1. Add 2.5 grams of sodium metabisulphite for every litre of the barrel’s total volume (0.4 oz./Imp. gal.).
2. Add 1.25 grams of citric acid for every litre of the barrel’s total volume (0.2 oz./Imp. gal).
3. Bung the barrel. Roll it to mix in the metabisulphite and citric acid.
4. Remove bung and finish filling barrel with cold water. Replace bung and let full barrel stand 48 hours.
5. Drain barrel. Rinse several times with cold water.
Shaved or rebuilt barrels
Shaved or rebuilt barrels have the first 6 mm of wood shaved off their interior surface. This means the barrel must be treated as if it were new. Follow the tightening, conditioning, and sanitizing instructions, above.
The safest way to store a barrel is to keep it full of wine at all times. Although this seems like a simple requirement, it may not always be easy to accomplish. Since this may not be possible at all times here are two ways to store your barrel.
An untreated empty barrel will quickly begin to produce moulds and bacteria, replacing the air in the barrel with an atmosphere high in SO2 will eliminate this problem.
1. Make sure the barrel is tight.
2. Rinse the barrel well and drain bung down for 24 hours.
3. Use one of the following methods to ensure bacteria free storage:
Method 1 - Sulphur Sticks
These should be burned in a device that will collect any drips of molten sulphur. Place the stick in the burner which is suspended from the bung. Light the stick, place in the barrel and allow to burn completely. Re-sulfur every 6-8 weeks.
225L barrel use approximately 1/4 - 1/3 stick
Method 2 - Sulfite Solution
Make up a 2% metabisulfate solution and place a small amount (10% of the barrels capacity) in the barrel. Replace solution every 6-8 weeks.
Occasionally barrels go sour, even if you are careful about sanitation. Never refill a barrel that has contained spoiled wine—the new wine will also go bad.