A Keyhole Fire can only be described as exactly as its name suggests, it looks like a keyhole, a large round part, where the main fire is located, which is attached to a rectangle, where the coals or smaller fire is. As coals develop in the main fire, they are scraped into the rectangular area, then used for cooking.
There is no specific fire laying method here, it is more focused on the management of the fire once it is set up to ensure a constant creation of coals are created for cooking on. This flow in turn gives more scope for temperature control in an outdoor cooking environment.
How to Build a Keyhole Fire
1/ Assess the location.This fire has relatively few needs, primarily a flat location, away from trees and overhead flammable items. As always consider the surroundings for fire hazards, wind direction and similar.
2/ Mark out the base. The keyhole shape of the fire is marked out using stones, brings or similar. The large circle of the main fire can be build first and should be at least 2 feet / 60cm in diameter, for more people this can be increased as required. On the upwind side create the rectangle, this should be about the size of the rack, pans and similar to allow space for all the equipment needed to cook the planned meal. This too is lined with stones or bricks.
3/ Lay the fire. In the main fire circle lay your favorite fire design such as a Log Cabin Fire or Tepee Fire
4/ Light the fire. Light the fire about an hour before you plan to cook to ensure it has time to burn down and create the coals needed for cooking.
5/ Maintaining the fire. The main fire needs to be continually maintained as long as coals are needed. The set-up allows for long cook time sand multiple pot meals that can be cooked with a reasonable amount of temperature control, as long as the main fire is well managed and there is always a fresh supply of coals being created when they are needed.
6/ Extinguishing the fire. Although this fire has some wind protection from the stone / brick surrounds it is still primarily exposed to the wind. If not extinguished correctly it has the potential to reignite. It should be dispersed within the stone boundary then be extinguished carefully with water. Do not leave until it is fully extinguished and cool to the touch otherwise it can re-ignite.