Birectifier Analysis of Clairin Le Rocher

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This post was mainly about testing a new “student” model of the birectifier that I built myself. Everything tested okay and this unit already shipped. The rum is also excellent, but unique. My theory is that Clairin Le Rocher may feature diacetyl which generates a buttery aroma. This can be a flaw in wine, but also a feature and here it contributes to the the blending personality of Le Rocher which I’ve been exploring. Whatever distinct note Le Rocher has, adds intrigue to a blend, particularly those with oak. It also lends itself to cocktails. Butteriness in a daiquiri? The note seems to change in the context where it is diluted but it still brings intrigue.

Diacetyl at low concentrations (and in combinations with other wine aroma compounds) will impart yeasty, nutty, toasty aromas Peynaud, 1947, Etievant, 1991. At high concentrations, it has a characteristic buttery aroma that is associated with a lactic character.

The idea to take away for blending is that if you dilute the diacetyl and draw in other aroma compounds, you may conjur the extraordinary!

I then jumped into baking. I have been increasingly exploring baking with the finest rums. Baking can be a better value proposition than actually drinking a fine rum, especially when we’re considering volume used. Would you give up a few sips to flavor an entire cake? Is fine rum the new vanilla bean? Saltanas were soaked in rum for a carrot cake.

My three other dinner companions and I also found the rum aroma easily salient in the cake and positively delightful. I’d go so far as to raise rum’s highest complement; radiant! Keep in mind, this is not a soaked cake. All that rum aroma easily survives baking.

Back to the rum. If a unique note, which may be diacetyl, is salient in the rum, will it be easy to spot with the birectifier? The short answer is no, but my guess is that it may reside in fraction 5.

This was not a particularly estery rum and we may easily say it was less estery than Clairin Sajous I profiled back in 2020. This low degree of esters (we’re talking ethyl acetate) relative to intensity of flavor may effect Rocher’s blending personality and give a higher affinity for oak. The idea there being that oak may not be easily compatible with esters and too high an ester count enflames the oak making it taste cheap. However, a lot more needs to be explored on this concept.

The fusel oil content in fraction 4 was low, raising the possibility this a fission yeast ferment described by professor Fahrasmane in 1988. Spontaneous fission yeast ferments are quite special and would put this rum in rare company. Besides just the intensity of the fusel oil, the higher alcohols characteristic of a fission yeast may be more butyls and less sharp amyls. Organoleptically, that may have been recognized in the “broad” character I described.

Titrating fusel oil is complicated and probably costs just as much in time & equipment expense as a birectifier. Chromatography would cost even more. With the birectifier we don’t get a number we can quote in a research paper, but just by organoleptic appraisal, a distiller can get a clear sense of what is there and how the fusel oil is framed by role model experience. The information is easily actionable and even kept for reference for future comparisons.

What is really interesting is a comparison to my fraction 5 from Clarin Sajous in 2020:

Fraction 5: Oil droplets all over the surface. The aroma here is far more complex than I imagined almost feels like it has intersecting facets. There is almost a green and delicate gin like pininess. Then there is a rounder ester aroma. I have only ever surveyed one rum before that had the vesouté aroma and I’m not sure if it is responsible for the fresh top notes you get here. I remember that other rum did not have so much depth to its fraction 5 as this one. There is a subtle acridness on the palate, likely from concentrated esters. In general this fraction 5 is far less concentrated than that of the heavier Jamaica rums and there is no distinct rum oil.

“Intersecting facets” vs. “flickers of another character”? There is a lot of complexity to these rums as revealed here. Few in the world are achieving this. Haitian rum does more than anyone else with less.

The later fractions and their detectable gustatory acidity showed us the heaviness of the ferment and evidence of pot distillation.


Fraction 1: Not overly concentrated. No abnormal character. Not particularly estery.

Fraction 2: Fairly neutral. Inline with expectations because fraction 1 was very light.

Fraction 3: Very neutral as expected.

Fraction 4: Detectable fusel oil, but possibly below average for a budding yeast; fission yeast ferment? Very broad for fusel oil, no sharp wraith like character.

Fraction 5: Visibly louched. Droplets all over the surface. Unique estery character. Flickers of another character; the missing diacetyl? Distinctly fruitier than other fraction 5 expressions that seems more “floral”. Very unique on the palate. Oilier than acrid. Nothing here is easy to understand but its clear its distinct and unique. Looking forward to letting this continue to evaporate and evolve. Over 24 hours later, this evolved and got more brooding like rum oil might appear. I think I detect a menthey kind of rum oil that may be TDN or TNN. Right off the cuff, cinnamon notes morphed into menthe.

Fraction 6: No carryover from fraction 5. Detectable gustatory acidity, possibly less than fraction 7.

Fraction 7: Possible less sweaty than fraction 8? Detectable gustatory acidity.

Fraction 8: Slightly stinky character. Not sure what it is. Detectable gustatory acidity. Evidence of pot distillation?

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