Soda Ash, also known as sodium carbonate, is primarily used to remove tartrates in wine barrels. Use 5 teaspoons per 3 gallons of barrel capacity or 1 pound in per 50 gallons. Dissolve soda ash in a few cups of hot water. Fill the barrel half full with hot water, and the soda ash solution. Shake or roll the barrel to mix the solution, and then top up with hot water. Roll the barrel several times during a 48-hour period. Then empty it and rinse several times until all the solution has been washed out.
Please note: Barrel care is a complicated process and there is no shortage of differing opinions and procedures, as well as variances in amounts and types of chemicals used and the length of contact time.