Cooking the boules

Article 2 of the rules – “Characteristics of approved boules” – discusses the requirements for approved boules (boules agréées). But it doesn’t provide all of the requirements for competition boules.

boules_on_the_grill_from_boules_de_leonThe FIPJP’s full requirements for certified boules (boules homologuées) are laid out in a separate document called Conditions Requises Pour L’homologation De Boules De Petanque De Competition (“Requirements for the Certification of Competition Petanque Boules”).

This document (in French) can be downloaded from the FIPJP website. (Look for “Règlement pour l’agrément de boules” toward the bottom of the page.) Or you can download our English translation from the “Rules of Petanque” website.


That second document — “Requirements for the Certification of Competition Petanque Boules” — gives the FIPJP’s technical requirements for competition petanque boules (size, weight, etc.). And it lays out the procedures that manufacturers must use to get official FIPJP certification for a product line of competition boules.

According to the Preamble, one of the goals of the document is

To insure the safety of players and spectators by providing binding standards for materials and manufacturing processes, with the goal of avoiding any risk – in particular, any risk of being hit by a piece of metal.

The document seems to take safety quite seriously. Section II, article 7 even specifies that the light coat of paint that manufacturers use to protect carbon steel balls from rust must be tested.

These coatings will be impact-resistant, and the manufacturer must conduct tests to prove that the products used generate no splinters that could be dangerous for users.

In keeping with the goal of safety, Section II, article 3 specifies a minimum and maximum permissable hardness for boules – 35 HRC for a soft boule, and 55 HRC for a hard boule. HRC is the measure of a boule’s hardness on the Rockwell C hardness index.

When a manufacturer submits an application for certification for a new model of boule, he must submit several pieces of information about it, including the material of which it is made and “the hardness and its method of production, and its means of verification” (I, 5).


Steel’s hardness is determined by the way it is heat-treated. When steel is being worked, it is first heated to a very high temperature and then cooled very quickly. This rapid cooling is called “quenching” and it leaves the steel in a very hard, brittle condition.

The steel is then reheated to a lower temperature and allowed to cool slowly. This is called “tempering” (or “annealing”) and it reduces the steel’s hardness and brittleness, making it softer, tougher, and more ductile. To achieve a particular level of softness, the steel is heated to a particular temperature, maintained at that temperature for a particular amount of time, and then allowed to cool slowly in still air.

The bottom line for petanque players and umpires is this –
If you know what you’re doing, you can make a steel boule softer by “cooking” it.


You need to know that the FIPJP has set a limit to the softness of certified boules, and a little bit about the chemistry of hardness, in order fully to understand Article 2’s specification that…

It is specifically forbidden to heat treat boules in order to modify the hardness given by the manufacturer.

Now that we have that information, we can understand what’s going on.

  • For reasons of safety and consistency, the FIPJP requires manufacturers to produce boules with a hardness between 35 and 55 HRC.
  • According to folk wisdom and petanque tradition, shooters want soft boules, to minimize rebound and increase their chances of making carreaux.
  • A trained engineer might be able to re-temper a certified boule, after it left the factory, to make it softer.
  • So on the theory that “if soft is good, softer is better”, a shooter might come up with the idea of re-tempering the softest boule that he could buy, to make it even softer than the 35 HRC permitted by the “Regulations for Certification”.

Article 2 specifically forbids that practice.


So, how can an umpire at a tournament detect a set of cooked boules?

Well there is this device, le balancier. I read about it on the educnaute-infos blog.

LeBalancier_device_to_test_boule_hardness
You take two boules and put them in the cradles. One boule simply hangs in its cradle. The other is pulled back to a specific distance and the device is cocked. Then the boule is released via a trigger.

The swinging boule hits the hanging boule and knocks it away, like the balls in a Newton’s cradle. A pointer indicates how far it was knocked. The distance it was knocked indicates the hardness of the boules.

Educnaute-infos says that it’s not used very much.


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