Wednesday, March 13, 2013

Vatican Reveals Recipes for Conclave Smoke

The papal conclave’s recipes for white and black smoke are a mystery no more. On Tuesday, the Vatican press office revealed the composition of the colored smoke used during the conclave to signal the results of the voting. Earlier, a Vatican spokesman had said only that the smoke was made “from several different elements.”

Both recipes are fairly standard pyrotechnical formulas. The white smoke, used to announce the election of a new pope, combines potassium chlorate, milk sugar (which serves as an easily ignitable fuel) and pine rosin, Vatican officials said in a statement. The black smoke, which was used Tuesday evening to signal that no one in the first round of balloting received the necessary two-thirds vote of the 115 cardinals, uses potassium perchlorate and anthracene (a component of coal tar), with sulfur as the fuel. Potassium chlorate and perchlorate are related compounds, but perchlorate is preferred in some formulations because it is more stable and safer.

The chemicals are electrically ignited in a special stove first used for the conclave of 2005, the statement said. The stove sits in the Sistine Chapel next to an older stove in which the ballots are burned; the colored smoke and the smoke from the ballots mix and travel up a long copper flue to the chapel roof, where the smoke is visible from St. Peter’s Square. A resistance wire is used to preheat the flue so it draws properly, and the flue has a fan as a backup to ensure that no smoke enters the chapel.

By HENRY FOUNTAIN

New York Times

March 12, 2013