Crystal Clear, or is it?
Luis Ayala Editor and Publisher
This month’s issue of “Got Rum?” is devoted to white rum, also known as clear, crystal, silver, platinum,”see-through” and other similar monikers. The irony of these names, however, is that they suggest a colorless liquid, which is only true for very high-proof and pure ethanol. Water, by itself, absorbs long wavelength colors but reflects the short wavelength ones, including blue. This is the reason why oceans appear to be blue and water, in large tanks, will also have a blueish tint to it.
When we use a spectrophotometer to compare high-proof rum (with an ABV above 94%) to typical bottle-proof rum (with an ABV of 40%), we can easily see how the water reduces the transparency of the alcohol, making it less clear. But the relationship between water and rum goes even deeper: high mineral underground or surface water is often used in the fermentation and distillation of rum, to dilute molasses and to cool down condensers. De-mineralized or deionized water is then used to proof down the alcohol to the desired strength.
Using the incorrect type of water, with the incorrect type of alcohol can lead to cloudiness, precipitations and/or incorrect pH and conductivity in the final product.
Treated water, devoid of chlorine, is also subject to contamination from algae and other micro- organisms. To avoid these problems, some distillers add alcohol to the water storage tanks reserved for proofing, to keep the water from going bad, thus highlighting another dimension of the ethanol-water complex relationship.
Even if you prefer drinking aged rums over their un-aged counterparts, knowing these facts should help you appreciate all the effort and thinking that goes into creating the cornerstone of the rum industry.
Cheers,
Luis Ayala, Editor and Publisher