Like other brewed herbs, "yerba mate" leaves are dried, chopped, and ground into a powder called "yerba". The "bombilla" is both a straw and a sieve. The end which is placed in the drink is wider, with small holes or slots that let the brewed liquid in, but block the chunky matter that makes up much of the mixture. A modern "bombilla" uses a straight tube with holes, or spring sleeve to act as a sieve. "Bombilla" means "light bulb" in Spanish, but locally it is "little pump" or "straw".
In some areas of the Middle Eastern countries of Syria and Lebanon it is also common to drink mate. The custom of drinking "mate" came from Arab emigrants from South America. Syria is the world's biggest importer of yerba mate in the world, importing 15,000 tons of yerba mate a year.
"Mate" is made differently in different places, with many arguments about which way is the best. In nearly all methods, the gourd is nearly filled with "yerba", and hot water (typically at 70–80 °C <nowiki>[</nowiki>160–180 °F<nowiki>]</nowiki> and never boiling) is added.
The most common way to make mate involves a careful arrangement of the "yerba" in the gourd before adding hot water. The gourd is filled one-half to three-quarters of the way with "yerba". Extra herbs may be added for either health or flavor benefits. This is most often done in Paraguay, where people get herbs from a local yuyera (herbalist). The "mate" is used as a base for their herbal infusions. When the gourd is filled, the preparer typically grasps it with their full hand. They cover the opening and roughly seal it with their palm. Then the "mate" is turned upside-down, and shaken vigorously, but briefly and with gradually decreasing force, in this inverted position causing the finest, most powdery particles of the "yerba" to settle toward the preparer's palm and the top of the mate.
Once the "yerba" is settled, the mate is carefully brought to a near-sideways angle, with the opening tilted just slightly upward of the base. The mate is then shaken very gently with a side-to-side motion. This further settles the "yerba" inside the gourd so that the finest particles move toward the opening and the "yerba" is layered along one side. The largest stems and other bits create a partition between the empty space on one side of the gourd and the lopsided pile of "yerba" on the other.
After arranging the "yerba" along one side of the gourd, the "mate" is carefully tilted back onto its base, minimizing further disturbances of the "yerba" as it is re-oriented to allow consumption. Some avalanche-like settling is normal, but is not desirable. The angled mound of "yerba" should remain, with its powdery peak still flat and mostly level with the top of the gourd. A layer of stems along its slope will slide downward and accumulate in the space opposite the "yerba" (though at least a portion should remain in place).
All of this careful settling of the "yerba" ensures that each sip contains as little particulate matter as possible, creating a smooth-running mate. The finest particles will then be as distant as possible from the filtering end of the "bombilla". With each draw, the smaller particles would inevitably move toward the "bombilla", but the larger particles and stems filter much of this out. A sloped arrangement provides consistent concentration and flavor with each filling of the "mate".
Now the "mate" is ready to receive the "bombilla". Many people choose to pour warm water into the "mate" before adding the "bombilla", while others insist that the "bombilla" is best inserted into dry "yerba". Wetting the "yerba" by gently pouring cool water into the empty space within the gourd until the water nearly reaches the top, and then allowing it to be absorbed into the yerba before adding the "bombilla", allows the preparer to carefully shape and "pack" the "yerba"<nowiki>'</nowiki>s slope with the "bombilla"<nowiki>'</nowiki>s filtering end, which makes the overall form of the "yerba" within the gourd more resilient and solid. Dry "yerba", on the other hand, allows a cleaner and easier insertion of the "bombilla", though care must be taken so as not to overly disturb the arrangement of the "yerba". Such a decision is entirely a personal or cultural preference. The "bombilla" is inserted with your thumb on the upper end of the bombilla, at an angle roughly perpendicular to the slope of the "yerba", so that its filtering end travels into the deepest part of the yerba and comes to rest near or against the opposite wall of the gourd.
Now the "yerba" may be brewed. If the "bombilla" was inserted into dry "yerba", the mate must first be filled once with warm water as above, then be allowed to absorb it completely (which generally takes no more than two or three minutes). Treating the "yerba" with cool water before the addition of hot water is essential, as it protects the herb from being scalded and from the chemical breakdown of some of its desirable nutrients. Hot water may then be added by carefully pouring it, as with the cool water before, into the cavity opposite the "yerba", until it reaches almost to the top of the gourd when the "yerba" is fully saturated. Care should be taken to maintain the dryness of the swollen top of the "yerba" beside the edge of the gourd's opening.
Once the hot water has been added, the mate is ready for drinking. It may be refilled many times before becoming washed out ("lavado") and losing its flavor. When this happens, the mound of "yerba" can be pushed from one side of the gourd to the other, allowing water to be added along its opposite side; this revives the "mate" for additional re-fillings.
"Mate" is traditionally drunk in a particular social setting, such as family gatherings or with friends. One person (known in Spanish as the "cebador") assumes the task of server. Typically, the cebador fills the gourd and drinks the "mate" completely to ensure that it is free of particulate matter and of good quality. The server subsequently refills the gourd and passes it to the next drinker who likewise drinks it all, without thanking the server. The ritual proceeds around the circle in this fashion until the "mate" becomes "lavado" ("washed out" or "flat"), typically after the gourd has been filled about ten times or more depending on the "yerba" used (well-aged "yerba mate" is typically more potent, and therefore provides a greater number of refills). When one has had his fill of "mate", he or she politely thanks the "cebador" passing the "mate" back at the same time.
The drink has a pungent taste like a cross between green tea and coffee, with hints of tobacco and oak. Some drinkers like to add sugar or honey, creating "mate dulce" (sweet "mate"), instead of sugarless "mate amargo" (bitter "mate"). It is considered bad for the gourd (especially for the natural (squash or wood) ones) to be used for "mate dulce" so it is normal for households with drinkers of both kinds to have two separate gourds.
Traditionally, natural gourds are used, though wood vessels, bamboo tubes and gourd-shaped "mates", made of ceramic or metal (stainless steel or even silver) are also common. Gourds are commonly decorated with silver, sporting decorative or heraldic designs with floral motifs.
Both the wood vessels and the gourds must undergo "curing" to get a better taste before being used for the first time and to ensure the long life of the gourd. Typically, to cure a gourd, the inside is first scraped with the tip of a bombilla to remove loose gourd particles. "Mate" herb and hot water is added next, and the mixture poured into the gourd. The mixture is left to sit overnight and the water is topped off periodically through the next 24 hours as the gourd absorbs the water. Finally the gourd is scraped out, emptied, and put in sunlight until completely dry.
It is common for a black mold to grow inside the gourd when it is stored. Some people will clean this out, others consider it an enhancement to the mate flavor.