Milk chocolate is a sweet chocolate that also contains powdered milk or condensed milk. In the United Kingdom and Ireland, milk chocolate must contain at least 20 % total dry cocoa solids; in the rest of the European Union, the minimum is 25%.  Production costs can be reduced by reducing the solids content of cocoa or by replacing cocoa butter with another fat. Cocoa farmers refuse to allow the resulting foods to be called «chocolate» because of the risk of a drop in demand for their plants.  According to Canada`s Food and Drug Regulations, a «chocolate product» is a food product derived from at least one «cocoa product» and containing at least one of the following: «chocolate, bittersweet chocolate, semi-sweet chocolate, dark chocolate, sweet chocolate, milk chocolate or white chocolate». A «cocoa product» is defined as a food product derived from cocoa beans and containing «cocoa nibs, cocoa mass, unsweetened chocolate, dark chocolate, chocolate liquor, cocoa, low-fat cocoa, cocoa powder or low-fat cocoa powder.» The penultimate process is called conching. A conch is a container filled with metal beads that act as mills. The mass of refined and mixed chocolate is kept in a liquid state by the heat of friction. Chocolate before conching has an uneven and grainy texture. The conching process creates smaller cocoa and sugar particles than the tongue can detect (usually about 20 μm) and reduces roughness, hence the soft feel in the mouth. The length of the conching process determines the final sweetness and quality of the chocolate.
High-quality chocolate is conched for about 72 hours, smaller classes about four to six hours. Once the process is complete, the chocolate mass is stored in tanks heated to about 45 to 50 °C (113 to 122 °F) until final processing.  In the EU, a product can be sold as chocolate if it contains up to 5% vegetable oil and must be labelled as «family milk chocolate» rather than «milk chocolate» if it contains 20% milk.  Some soft drinks contain chocolate, such as chocolate milk, hot chocolate, chocolate milkshakes and tejate. Some alcoholic liquors are flavored with chocolate, such as chocolate liqueur and cocoa cream. Chocolate is a popular flavor of ice cream and pudding, and chocolate sauce is often added as a topping on sundaes. Caffè Moka is an espresso drink that contains chocolate. George Foreman Grills removed the fat and flavor from Snackwell`s cookies and pantries filled with Slim Fast Shake with a meat and chocolate cake flavor. Dark chocolate is made by adding fat and sugar to the cocoa blend. The U.S. Food and Drug Administration calls this «sweet chocolate» and requires a 15% concentration of chocolate liquor. European regulations require at least 35% cocoa solids.
 A higher amount of cocoa solids indicates more bitterness. Semi-sweet chocolate is a dark chocolate with a low sugar content. Bittersweet chocolate is a chocolate liquor to which a little sugar (usually a third), plus cocoa butter and vanilla are added.  It contains less sugar and more alcohol than semi-sweet chocolate, but the two are interchangeable in baking. It is also known to last two years when stored properly. As of 2017, there is no high-quality evidence indicating that dark chocolate significantly affects blood pressure or offers other health benefits.  Poorly tempered or untempered chocolate may have whitish spots on the dark chocolate part called the chocolate flower; This is an indication that sugar or fat has separated due to poor storage. It is non-toxic and safe to consume.  Chocolate tempering machines (or temperature control machines) with computer control can be used to produce consistently tempered chocolate.
In particular, continuous temperature control machines are used in high-volume applications. Aasted, Sollich and Bühler, three manufacturers of commercial chocolate equipment, described various processes and equipment for continuous annealing of chocolate, with a focus now on energy efficiency. In general, melted chocolate is cooled to 40–50 °C in heat exchangers at crystallization temperatures of about 26–30 °C, passed through a quenching column of spinners to induce shear, and then slightly heated to melt unwanted crystalline formations again.   The Aztecs could not grow cocoa themselves because their homeland in the Mexican highlands did not suit them, so chocolate was a luxury imported into the empire.  Those who lived in the territories ruled by the Aztecs had to offer cocoa beans against payment of the tax, which they considered a «tribute.»  Cocoa beans were often used as currency.  For example, the Aztecs used a system in which a turkey cost 100 cocoa beans and a fresh avocado three beans.  The last process is called quenching. The uncontrolled crystallization of cocoa butter usually results in crystals of different sizes, some or all of which are large enough to be seen with the naked eye. This makes the surface of the chocolate appear speckled and matte, and the chocolate crumbles instead of breaking when broken.
  The uniform shine and crispy bite of properly processed chocolate is the result of constantly small cocoa butter crystals created by the tempering process. White chocolate was first introduced to the United States in 1946 by Frederick E. Hebert of Hebert Candies in Shrewsbury, Massachusetts, near Boston, after tasting «white coat» candies on a trip to Europe.   In the 2000s, some chocolate producers began engaging in fair trade initiatives to address concerns about the marginalization of cocoa workers in developing countries. Traditionally, Africa and other developing countries received low prices for their exported products such as cocoa, which led to poverty. Fairtrade aims to establish a direct trade system for developing countries to counter this unfair system.  One solution to fair labour practices is for farmers to be part of an agricultural co-operative. Cooperatives pay farmers a fair price for their cocoa so that farmers have enough money for food, clothing and school fees.  One of the most important principles of fair trade is that farmers receive a fair price, but this does not mean that the largest amount of money paid for Fairtrade cocoa goes directly to farmers.