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.