It's easiest to quote from my book ...
<i>"Quite simply 'sugarbakers' were those who worked in Britain’s sugarhouses or sugar refineries. As the 17th century European sugar industry was dominated by Amsterdam and Hamburg, the name was derived from the Dutch 'suikerbakker' and the German 'Zuckerbäcker', and it was variously written as sugar baker, sugar-baker, or sugarbaker. The English language had no equivalent word or phrase for ‘worker in a sugarhouse’, so the word was not translated from the German but was a German word, brought here by Germans, spoken by Germans, and entered into our language, albeit for a short time, because those who heard it understood it and accepted it without question. Particularly in the early years, sugarbaker referred to worker and owner alike. 'Sugarbaker' is the normal form you’ll find in documents written in Britain by those associated with the churches, schools, charities and other organisations within the German communities."</i> (Sugarbakers - from Sweat to Sweetness, by Bryan Mawer, pub AGFHS 2011)
In 1691 the job was an unpleasant one. The sugar, at all stages, was boiled in large, open, copper pans over open fires. The process of refining involved boiling with water and eggs (later bulls' blood) as the albumen collected many of the impurities, filtering, repeated boilings to reduce the water content ready for crystalisation, and pouring the very hot liquid sugar into moulds where they would cool and form conical sugar loaves.
The men would work very long hours, almost naked, in temperatures over 100 degrees, with the dangers of fire, scolding, falling through pulley holes, falling into pans, etc, and with only weak beer to drink as the water was so poor.
For a description of the work in 1876, when there had been some improvements (!!), take a look at a page on my website ...
www.mawer.clara.net/greenwood.html .
So the knowledge and experience of sugar refining would have helped in the distillery. As far as I know there was no refining in Deptford until 1770, so the City of London would have been the most likely location.
Sorry to ramble, but hope of use.