carbon dioxide or CO2, a naturally occurring atmospheric gas, commonly encountered as the sparkle in soft drinks, beers, and sparkling wines. Its content in the atmosphere is only about 0.03%; yet upon that small amount depends the growth of all living systems, including man, vines, yeasts, bacteria, all plants, and the existence of all fauna depending on them for food. Not least, it is the ultimate raw material of wine and, via a series of biochemical reactions involving the grapevine, yeast cells, and the consumer, results in carbon dioxide’s being both assimilated and produced.
