science & techanalysisThe Conversation: Arts + Culture (US)
What is black garlic? How heat and humidity turn a pungent ingredient mild and slightly sweet
Black garlic is ordinary garlic that has been kept warm and humid for several weeks to months, usually in chambers that hold exact temperature and moisture. No microorganisms are added. Instead, heat drives Maillard reactions between sugars and amino acids, which darken the cloves and create sweet, savoury flavour compounds. The heat also breaks down allicin, the compound responsible for raw garlic's sharp smell and taste, and softens the texture until it is spreadable. The technique was developed in Japan in the late 20th century.
The Maillard reaction happens when reducing sugars and amino acids are heated together, producing brown pigments and new aroma compounds. Slow heating in humid conditions also softens cell walls, and the breakdown of allicin reduces garlic's sharp bite.
Black garlic shows how a simple change in heat and humidity can transform a familiar ingredient. Its health claims are still being studied, and most evidence so far comes from lab and animal studies rather than human trials.
Long, low-temperature cooking that drives Maillard browning also gives other foods, such as caramelised onions and dulce de leche, their depth of flavour.
The Conversation
Illustrative photo · Foodista, CC BY 2.0, via Wikimedia Commons
