Black garlic is a type of aged garlic that is deeply colored brown. The color is a result of the Maillard reaction or caramelization, not fermentation. It was first used as a food ingredient in Asian cuisine. It is made by heating whole bulbs of garlic (Allium sativum) over the course of several weeks, a process that results in black cloves. The taste is sweet and syrupy with hints of balsamic vinegar or tamarind.Black garlic's popularity has spread around the world as it has become a sought-after ingredient used in both home-cooking and high-end cuisine.

History

In Korea, black garlic was developed as a health product and it is still perceived as such. It is sometimes added to energy drinks,  and in Thailand is claimed to increase the consumer's longevity.

Production

Black garlic is made when heads of garlic are aged under specialized conditions of heat and humidity. Bulbs are kept in a humidity-controlled environment from 80 to 90% at temperatures that range from 60 to 90 °C (140 to 190 °F) for 15 to 90 days (typically 85%, 70 °C, 40 days). There are no additives, preservatives, or burning of any kind. The enzymes that give fresh garlic its sharpness break down. Those conditions are thought to facilitate the Maillard reaction, the chemical process that produces new flavour compounds responsible for the deep taste of seared meat and fried onions. The cloves turn black and develop a sticky date-like texture.

Bacterial endophytes capable of fermentation and with a strong ability of heat resistance have been identified in common garlic and black garlic. These may have relevance to black garlic production.

Culinary uses

In black garlic, the garlic flavor is softened such that it almost or entirely disappears depending on the length of time it is heated. Additionally, its flavor is dependent on that of the fresh garlic that was used to make it. Garlic with a higher sugar content produces a milder, more caramel-like flavor, whereas garlic with a low sugar content produces a sharper, somewhat more acidic flavor, similar in character to tomato paste. Burnt flavors may also be present if the garlic was heated for too long at too high a temperature or not long enough: during heating, the garlic turns black in color well before the full extent of its sweetness is able to develop.

Black garlic can be eaten alone, on bread, or used in soups, sauces, crushed into a mayonnaise or simply tossed into a vegetable dish. A vinaigrette can be made with black garlic, sherry vinegar, soy, a neutral oil, and Dijon mustard. Its softness increases with water content.

Unlike the vegetable from which it is made, white garlic, black garlic has a very subtle and muted flavor that is easily overpowered.

Because of its delicate and muted flavors, a considerably larger amount of black garlic must be used in comparison to white garlic in order to achieve a similar level of intensity. Additionally, black garlic cannot be used in place of white garlic. If a garlic flavor is desired in addition to the flavor of black garlic, then fresh garlic must be added.

One method to release the subtle flavors of black garlic is to knead a peeled clove between the fingers until its structure is thoroughly broken down and then to dissolve the resulting paste in a small amount of hot water. This produces a dark brown, coffee-colored suspension of the fibrous black garlic particles in a solution that carries most of its flavor, acidity, and sugar content. This liquid may then be added to foods that are otherwise neutral in flavor (like, for example, mashed potatoes) to better showcase the flavor of the black garlic.

Likely owing to its harsh and concentrated odor, the potent reputation of fresh garlic, and the association of Maillard reactions with the browning of meat, it is a common misconception that black garlic has a "meaty" flavor. It does not. It is commonly eaten on its own by enthusiasts, who sometimes liken the flavor to a savory, slightly acidic caramel candy or to sweet tamarind fruit. The most prominent flavor it imparts is sweetness when used in high concentrations and when used in low concentrations, provided that there are no other flavors to compete with that of the black garlic, the flavor and aroma are somewhat similar to those of instant coffee, though without any bitterness.