The Scoville Organoleptic Test is not infallible, as it based on the taste perceptions of five human tasters, but it does provide a reliable guide to the relative strength of the capsaicin oil content of a species or hybrid of chili pepper.
Although the Bhut Jolokia is the "hottest" chile in the world, with a Scoville rating of 1 million, it is not common in Brazil, nor is its use traditional. Certain regional cuisines of Brazil do make extensive use of chilis, and chili "heat" is an important part of their flavor profiles. It's interesting to see where the chilis commonly used in Brazilian cuisine fit on the Scoville scale, in comparison to other Brazilian chilis, and to other chiles used elsewhere in the world.
Here is a basic rundown of the relative "heat" of a number of Brazilian and non-Brazilian chilis, starting with the Bhut Jolokia, the world's hottest, with following chilis becoming progressively milder. The chilis are broken into three group: hot, medium, and mild.
Bhut Jolokia (Scoville 1,000,000)
The hottest in the world, colored red and brown. Don't try to eat uncooked.
Red Savina (up to Scoville 580,000)
Hybridized in California, with undulating shape. Makes good sauces and preserves.
Habanero (Scoville 500,000)
When ripe very hot. Various colors. Used in making salsas, moles and chutneys.
Scotch Bonnet (Scoville 250,000)
Flattened and irregular. Fruity aroma. Used in Caribbean sauces, like jerk.
Malagueta (Scoville 100,000)
Hottest Brazilian chili on this list. Iconic chili of Bahia. Goes well with fish and meat dishes.
Murupi (Scoville 60,000)
Aromatic. Abundant in the north of Brazil, where it is preserved in whey.
Fidalga (Scoville 50,000)
Common in the states of Mato Grosso and São Paulo. Makes good sauces and preserves, and accompanies salads.
Pimenta-de-bode (Scoville 50,000)
In the state of Goiás it is used to flavor almost all of traditional daily dishes.
Cayenne (up to Scoville 50,000)
Eaten dried and ground in Africa and India. Indispensable in Cajun cooking.
Tabasco (up to Scoville 50,000)
Elongated, colored red or yellow. Highly flavored, used primarily in sauces, including Tabasco Sauce.
Cumari (up to Scoville 50,000)
Brazilian green chili, with small egg-shaped fruit. Can be eaten fresh or cooked in sauces.
Pimenta-de-cheiro (Scoville 20,000)
Color varies from light green to bright yellow. Common in the north and southeast of Brazil. Aromatic.
Dedo-de-Moça (Scoville 15,000)
Green and elongated. When dried and ground it is known in the south of Brazil as pimenta-calabresa.
Jalapeño (Scoville 5,000)
Along with the tabasco chili, it is the most consumed in the USA. Makes excellent sauces.
Biquinho (Scoville 1,000)
Very mild. Small and sweet, it is used in sauces, pickled or eaten raw.
The chilis in this list that are used most in Brazilian cuisine represent a good sampling of Brazil's chili harvest, but certainly not the totality. There are literally thousands of varieties of chili peppers that are used daily by chefs and cooks in the creation of Brazilian cuisine, both traditional and contemporary. From the relative ranking, you can see that Brazilian gastronomy is not afraid of hot chilis; on the other hand, with the exception of the Bahian regional cuisine, is it among the world's "spiciest" cuisines. The contribution of chilis to the flavors of Brazil is most often in the form of a hot chili sauce, and thus the amount of heat desired is very much a personal one. One person at the table might want to add 500,000 Scoville units to his or her meal, another 5,000 and another none at all. By keeping the "heat" in a tabletop sauce, all these options are open to the Brazilian diner.