Cocaine sulfate
Cocaine sulfate is produced by macerating coca leaves along with water that has been acidulated with sulfuric acid, or a aromatic-based solvent, like kerosene or benzene. This is often accomplished by putting the ingredients into a vat and stamping on it, in a manner similar to the traditional method for crushing grapes. After the cocaine is extracted, the water is evaporated to yield a pasty mass of impure cocaine sulfate.

The sulfate itself is an intermediate step to producing cocaine hydrochloride. In South America, it is commonly smoked along with tobacco, and is known as pasta, basuco, basa, pitillo, paco or simply paste. It is also gaining popularity as a cheap drug (.30-.70 U.S. cents per "hit" or dose) in Argentina.


Freebase
As the name implies, “freebase” is the base form of cocaine, as opposed to the salt form of cocaine hydrochloride. Whereas cocaine hydrochloride is extremely soluble in water, cocaine base is insoluble in water and is therefore not suitable for drinking, snorting or injecting. Cocaine hydrochloride is not well-suited for smoking because the temperature at which it vaporizes is very high, and close to the temperature at which it burns; however, cocaine base vaporizes at a low temperature, which makes it suitable for inhalation.

Smoking freebase is preferred by many users because the cocaine is absorbed immediately into blood via the lungs, where it reaches the brain in about five seconds. The rush is much more intense than sniffing the same amount of cocaine nasally, but the effects do not last as long. The peak of the freebase rush is over almost as soon as the user exhales the vapor, but the high typically lasts 5–10 minutes afterward. What makes freebasing particularly dangerous is that users typically don't wait that long for their next hit and will continue to smoke freebase until none is left. These effects are similar to those that can be achieved by injecting or “slamming” cocaine hydrochloride, but without the risks associated with intravenous drug use (though there are other serious risks associated with smoking freebase).

Freebase cocaine is produced by first dissolving cocaine hydrochloride in water. Once dissolved in water, cocaine hydrochloride (Coc HCl) dissociates into protonated cocaine ion (Coc-H+) and chloride ion (Cl–). Any solids that remain in the solution are not cocaine (they are part of the cut) and are removed by filtering. A base, typically ammonia (NH3), is added to the solution. The following net chemical reaction takes place:

Coc-H+Cl– + NH3 → Coc + NH4Cl
As freebase cocaine (Coc) is insoluble in water, it precipitates and the solution becomes cloudy. To recover the freebase, a nonpolar solvent like diethyl ether is added to the solution: Because freebase is highly soluble in ether, a vigorous shaking of the mixture results in the freebase being dissolved in the ether. As ether is insoluble in water, it can be siphoned off. The ether is then evaporated, leaving behind the cocaine base.

Handling diethyl ether is dangerous because ether is extremely flammable, its vapors are heavier than air and can “creep” from an open bottle, and in the presence of oxygen it can form peroxides, which can spontaneously combust. Demonstrative of the dangers of the practice, the famous comedian Richard Pryor used to perform a well known skit in which he poked fun at himself over a 1980 incident in which he caused an explosion and set himself on fire while attempting to smoke “freebase”, presumably while still wet with ether.


Crack cocaine
A pile of crack cocaine ‘rocks’.Due to the dangers of using ether to produce pure freebase cocaine, cocaine producers began to omit the step of removing the freebase cocaine precipitate from the ammonia mixture. Typically, filtration processes are also omitted. The end result of this process is that the cut, in addition to the ammonium salt (NH4Cl), remains in the freebase cocaine after the mixture is evaporated. The “rock” that is thus formed also contains a small amount of water. Sodium bicarbonate is also preferred in preparing the freebase, for when commonly "cooked" the ratio is 50/50 to 40/60 percent cocaine/bicarbonate. This acts as a filler which extends the overall profitability of illicit sales. Crack cocaine may be reprocessed in small quantities with water (users refer to the resultant product as "cookback"). This removes the residual bicarbonate, and any adulterants or cuts that have been used in the previous handling of the cocaine and leaves a relatively pure, anhydrous cocaine base.

When the rock is heated, this water boils, making a crackling sound (hence the onomatopoeic “crack”). Baking soda is now most often used as a base rather than ammonia for reasons of lowered stench and toxicity; however, any weak base can be used to make crack cocaine. Strong bases, such as sodium hydroxide, tend to hydrolyze some of the cocaine into non-psychoactive ecgonine.

The net reaction when using baking soda (also called sodium bicarbonate, with a chemical formula of NaHCO3) is:

Coc-H+Cl– + NaHCO3 → Coc + H2O + CO2 + NaCl
Crack is unique because it offers a strong cocaine experience in small, low-priced packages. In the United States, crack cocaine is often sold in small, inexpensive dosage units frequently known as a "blast" (equivalent to one hit or a dollars worth), “nickels”, “nickel rocks”, or "bumps" (referring to the price of $5.00), and also “dimes”, “dime rocks”, or "boulders" and sometimes as “twenties”, “solids", "slabs" and “forties.” The quantity provided by such a purchase varies depending upon many factors, such as local availability, which is affected by geographic location. A twenty may yield a quarter gram or half gram on average, yielding 30 minutes to an hour of effect if hits are taken every few minutes. After the $20 or $40 mark, crack and powder cocaine are sold in grams or fractions of ounces. At the intermediate level, crack cocaine is sold either by weight in ounces, referred to by terms such as "eight-ball" (one-eighth of an ounce) or "quarter" and "half" respectively. In the alternate, $20 pieces of crack cocaine are aggregated in units of "fifty pack" and "hundred pack", referring to the number of pieces. At this level, the wholesale price is approximately half the street sale price.

Crack cocaine was extremely popular in the mid- and late 1980s in a period known as the Crack Epidemic, especially in inner cities, though its popularity declined through the 1990s in the United States. There were major anti-drug campaigns launched in the U.S. to try and cull its popularity, the most popular being a series of ads featuring the slogan "The Thrill Can Kill". However, there has been an increase in popularity within Canada in the recent years, where it has been estimated that the drug has become a multi-billion dollar 'industry'.

Although consisting of the same active drug as powder cocaine, crack cocaine in the United States is seen as a drug primarily by and for the inner-city poor; the stereotypical "crack head" is poor, urban, and usually homeless. While insufflated powder cocaine has an associated glamour attributed to its popularity among mostly middle and upper class whites (as well as musicians and entertainers), crack is perceived as a skid row drug of squalor and desperation. The U.S. federal trafficking penalties deal far more harshly towards crack when compared to powdered cocaine. Possession of five grams of crack (or over 500 grams of powder) carries a minimum sentence of five years imprisonment in the US.