This is a short fun one from the 1903 International Sugar Journal. Many of us think of old school rum washes as being quite dirty, but what toll did it take on equipment? And what does it tell us about Arroyo’s focus a few decades later?
By 1903 sulphuric acid was in wide spread use to acidity fermentations and that led to lots of salt deposits.
So all of the biggest concerns were from commodity rums produced on continuous column stills and not the fine rums produced on pot stills where they could simply discharge and then flush out.
This phenomenon where alcohol changes how the crystals form may be why I’ve had much better success creating sugar cubes in an alcohol/water solution than in water alone (a project from probably six years ago). Very interesting.
What he goes on to explain is that sugar and acidity in the wash increase the solubility of gypsum so that 1 part to 400 part drops considerably. Gypsum actually precipitates as the wash ferments because the sugar content decreases.
These ideas are before the era of the Alfa Laval continuous centrifuge.
It would be Arroyo’s focus to go on and solve a lot of these problems with new ideas in molasses pre-treatment which resulted in significant advances to commodity rum production. It is hard to say if Arroyo faced the exact same challenges. As sugar producers gained increased chemical control and gathered more data, they were able to produce higher quality molasses. A lot of what Arroyo removed from molasses was not exactly gypsum but gums and other materials that could impede fermentation besides clogging a continuous still.