5 gallons lukewarm spring water, (approximately 95°F)
1 package (1/4 ounce/7 g) dry active yeast
1 cup pre-boiled water, (cooled to 85° to 95°F)
raisins (one per bottle)
Sanitize bottles and equipment in mild bleach solution, 2 ounces per 5 gallons cold water. Rinse several times with tap water inside and out.
Shake root beer concentrate well. Mix with sugar in a 5-gallon container. (DO NOT USE ALUMINUM). Stir in spring water.
Dissolve yeast in 1 cup pre-boiled water. Allow yeast to dissolve undisturbed 10 to 15 minutes. Add to sugar mixture and stir well.
Drop a raisin into each bottle.
Bottle immediately, leaving 2-inch space at top of bottle. Cap tightly.
Store each bottle on its side in a warm place (70° to 80°F) for 1 to 2 days, then store upright in refrigerator at 40° to 45°F for additional 3 to 4 days. Carbonation is complete when raisin expands fully. Keep refrigerated and consume within 7 to 8 days.