Rum Aging Science American Oak Barrels
Rum Aging Science Oak barrels
Introduction
In our first 12-part series, published from January through December 2020, we explored the transformation of rum, while aging in an ex-whiskey barrel. We selected an ex-whiskey barrel for that initial series because the majority of the rum aged around the world employs this type of barrel. The reason for the popularity of this choice is the fact that whiskey producers are required to age their spirit in new oak barrels and, once emptied, they cannot re-fill the barrels, thus creating a surplus of barrels that many other spirits are happy to use in their aging programs.
During the course of the first series, we received a considerable number of inquiries, asking how the results presented would differ if we were using new barrels. This new 12-part series is devoted specifically to address this topic: we will be conducting the same type of research as we did previously, examining the month-to-month changes to the rum while it ages in a new barrel, but also presenting side-by-side comparisons to the corresponding results from the used barrels.There are many different levels of heat treatment that can be applied to a new barrel. This series focuses exclusively on American Oak with a Char #1 (staves and heads), from Independent Stave Company/Missouri Cooperage. Future series will explore different Char and toast level combinations, as well as, barrels constructed using French Oak.
June’s Weather
June’s temperatures announced the impending arrival of summer, with daily highs and lows more in-line with historical Texas’ weather. Rains at the end of the month brought in cooler air while also increasing the humidity in the air. Working in the aging cellar is like being in a sauna, surrounded by rum barrels!
June's temperature
It’ll be interesting to see the ABV and pH are impacted by the spike in relative humidity, combined with the high temperatures we are experiencing.
Humidity for June
Seasonal Weather
July and August have historically been the two hottest months of the year in our part of the world, meaning we expect to have the most “maturation” occurring inside our barrels (accompanied by the most evaporation losses too).
Maturation and Evaporation graph for June
These are the pH readings, as recorded on the 1st day of each month, compared to the rum from the previous series, which was aged in an ex-Bourbon barrel:
Ph readings in barrel
Rum aging for July
And these are the changes in ABV % readings (as of first day of each month), also compared to the ex-Bourbon barrel:
ABV readings for June
Color: The monthly change in color continues to be significant, even to the naked eye. The last sample retrieved from the barrel has deeper reddish-copper hues, that make it more appealing.
Taste: The rum’s flavor has a more pronounced oak dimension, as suggested by the color. The majority of the extracted tannins are still “harsh,” meaning un-oxidized, but are nonetheless helping to make the rum more interesting and complex. The reduced pH (increased acidity) is also starting to come across, with enhanced fruity notes starting to develop.
Join us again next month, as we continue to explore the fascinating world of rum aging!