He returned to New York in an unsuccessful effort to recover debts owed by his agents and on visiting the south he became trapped by the conflict.
After many pleas, and the intercession of President Lincoln himself, Charles was released in November 1862, but he returned to France sick and bankrupt.
His business was subsequently saved because a debt was repaid in deeds to land in Coronado where, shortly afterwards, there was a silver boom which turned the obscure village of Denver into valuable estate.
Charles Heidsieck focused on selecting, blending and ageing wines to produce higher quality champagnes, buying grapes from individual growers.
In 1867 he purchased several old chalk quarries, called crayères which dated from the Gallo-Roman era, in order to create optimal conditions for wine maturation.