Soda Ash, also known as sodium carbonate (Na2CO3), is the sodium salt of carbonic acid (soluble in water). Primarily used to remove tartrates in wine barrels. Use two ounces of soda ash for each three gallons of water. Fill the barrel half full with water as hot as you can get it. Then add the soda ash that has previously been dissolved in a little hot water. Shake or roll the barrel until the solution is well mixed. Now finish filling with water as hot as you can get it. Bung the barrel tight and roll it around to agitate it. Roll the barrel several times during a 12-hour period. Then empty it and rinse several times until all the solution has been washed out.