Rum Aging Science - American Oak: New vs. Used Part IV

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                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.

              March’s Weather

We are happy to report that, after experiencing a “crazy cold” February here in Texas, March’s temperatures have returned to “crazy normal,” with highs in the 80s and lows in the 50s.

The daily deltas (difference between high and low temperatures) are substantial, allowing for the rum inside the barrels to expand and contract more, resulting in higher rates of extraction from the oak.

Humidity levels inside the cellar are showing fluctuations similar to the ones we saw before winter.  The humidity is affected in great part by seasonal rains and the intensity of the winds.

Above: Color transformation of the rum in a new charred barrel. One month in a new barrel extracted more wood flavor and tannins than 12 months in a used barrel. The rum color continues to darken, showcasing now reddish- copper hues.

Below: The new American oak barrel where the rum has been patiently aging since January 1st of this year.

These are the pH readings, as recorded on the 1st day of each month, compared to the rum from the previous series (2020), which was aged in an ex-Bourbon barrel:

And these are the changes in ABV % readings, also compared to the ex-Bourbon barrel:

Color: The color continues to darken, with increased intensity in copper, red and mahogany tones.

Taste and Aroma: The aroma is starting to reveal traces of lactones beyond the dominant tannin notes.  The taste continues to be rather flat and un-interesting, with all the oak components of the flavor being mostly flat (lacking depth) and having high astringency (not oxidized yet).

Join us again next month, as we continue to explore the fascinating world of rum aging!