Introduction
Aging is the most value-added transformation that a rum can undergo while at a distillery or aging cellar. But aging all spirits involves so many variables, that distillers/cellar masters often leave decisions to chance. In this new series, The Rum University and Rum Central will monitor and share monthly data from a single barrel, so that readers can better understand the transformations that rum undergoes while aging.
Different climate conditions around the world affect these transformations in different ways. While the effects are universal, the results presented in this new series will be those from Rum Central’s Florence warehouse, located in Central Texas, USA.
Series Overview
The January 2020 issue of “Got Rum?” covers in detail the goals of this series, as well as, descriptions of the different equipment being used to gather the data.
As a result of feedback from our readers, we’ve added extra temperature/humidity data loggers to different locations within the warehouse. These additional data points will -hopefully- illustrate how much these conditions differ even under the same roof. So, starting February 1st we will be recording hourly readings from three different locations within the aging cellar:
- Channel 1 - Central area (where our single barrel is located)
- Channel 2 - East side of building and
- Channel 3 - West side of the building
January’s Weather
The month of January was -not surprisingly- very cold. The average low temperature around the barrel was 11.2C/ 52.16F. The average high temperature was 18.1C/64.58F. Humidity inside the cellar ranged from 57% to 89%.
January's Weather
The Rum
As stated in last month’s article, we know very well what type of chemical changes happen to the rum inside the barrel. From an Experimental Design perspective, we did not question if these changes would take place, but rather how fast they would occur. Here are our observations.
Color: After only 30 (very cold) days inside the barrel, we did not really expect the rum to have changed in color too drastically. The sample retrieved shows only slightly yellow coloration, almost imperceptible to the naked eye. Comparing against the control, with a white background, makes the color a bit more noticeable (see photo below).
Samples of Rum Aging Science
Aroma: The aroma is still predominantly that of the control (unaged) sample, only hints of oak are present in the background.
pH: While working in Central/South America and the Caribbean, we collected a lot of data regarding rum’s pH changes inside the barrels, but usually at annual or semi-annual intervals. We knew from experience and from science that the pH would go down, but didn’t really expect the jump to be as rapid as it was, especially given the low temperature in the cellar. The rum that went into the barrel 30 days earlier had a pH of 7.04 and after only one month of aging in the cellar, the pH dropped to 5.67.
ABV: The barrel’s entry proof was 63.43% ABV and one month later that number was 63.42%.
What’s Next?
January is the coldest month of the year in Central Texas. February’s average temperature should be around 6 degrees F warmer, resulting in a faster extraction rate and in slightly higher evaporation loss. See you again in one month!