Treacle (//) is any uncrystallised syrup made during the refining of sugar. The most common forms of treacle are golden syrup, a pale variety, and a darker variety known as black treacle, similar to molasses. Black treacle has a distinctively strong, slightly bitter flavour, and a richer colour than golden syrup. Golden syrup treacle is a common sweetener and condiment in British cuisine, found in such dishes as treacle tart and treacle sponge pudding.
Historically, the Middle English term treacle was used by herbalists and apothecaries to describe a medicine (also called theriac or theriaca), composed of many ingredients, that was used as an antidote for poisons, snakebites, and various other ailments. Triacle comes from the Old French triacle, in turn from (unattested and reconstructed) Vulgar Latin *triacula, which comes from Latin theriaca, the latinisation of the Greek θηριακή (thēriakē), the feminine of θηριακός (thēriakos), 'concerning venomous beasts', which comes from θηρίον (thērion), 'wild animal, beast'.
Treacle is made from the syrup that remains after sugar is refined. Raw sugars are first treated in a process called affination. When dissolved, the resulting liquor contains the minimum of dissolved non-sugars to be removed by treatment with activated carbon or bone char. The dark-coloured washings[clarification needed] are treated separately, without carbon or bone char. They are boiled to grain (i.e. until sugar crystals precipitate out) in a vacuum pan, forming a low-grade massecuite (boiled mass) which is centrifuged, yielding a brown sugar and a liquid by-product—treacle. Black treacle naturally contains relatively high levels of sulphite (>100ppm, expressed in sulphur dioxide equivalent). These levels are deemed safe for the majority of the population, but some allergic and respiratory reactions have been reported particularly amongst asthmatics, so that the United States Food and Drug Administration requires that levels over 10ppm, i.e. >10mg/kg, be declared on the ingredients label.
A traditional Cornish fisherman's celebratory drink is "Mahogany", made from two parts local gin—now usually Plymouth Gin—mixed with one part black treacle.
In chapter 7 of Lewis Carroll's Alice's Adventures in Wonderland, the Dormouse tells the story of Elsie, Lacie, and Tillie, who live at the bottom of a well. This confuses Alice, who interrupts to ask what they ate for sustenance. "The Dormouse again took a minute or two to think about it, and then said, 'It was a treacle-well.'" This is an allusion to the so-called "treacle well", the curative St Margaret's Well at Binsey, Oxfordshire.