Aged rum to white rum

[Dokimos]

An experiment for making white rum

I've made white rums before using the following methods on separate occasions:

1. 100% molases, distill to 95% ABV, no muck or dunder, just rum feints in spirit run, tight cuts

2. 100% molasses, double pot still, clean dunder in wash, muck in the spirit run, somewhat wide cuts

3. 100% molasses, reflux to 85% ABV, no muck or dunder, tight cuts

4. Half and half sugar contribution from white sugar and molasses, clean dunder in wash, double pot still, muck in spirit run, moderately tight cuts

5. Half and half molasses and sugar, double pot still, muck in fermentation and spirit run, wide cuts

I like big, bold flavors (Islay scotch and Jamaican rum are a couple favorites of mine) so attempts 2 and 4 were well within my wheelhouse after several months of aging. However I never quite liked the flavor of my unaged rums. I think there is something in there that needed to chemically change in order to be good according to my tastes. That explains why most white rums are barrel aged then filtered of color. However the refluxed rums I made (attempts 1 and 3) didn't have the ester flavors (treble) or rich molasses notes (bass) that I enjoy in some commercial white rums.

Also, I don't have the filtering technology that commercial spirits have, so I decided to try something else. I wanted to try an alternate way of making a flavorful, estery white rum. So here's what I did.

I fermented an all molasses wash with US-05 and refluxed to 85% ABV with a tight heart cut to get a good molasses base with minimal off flavors. This was attempt 3 from above. Then I aged it for 9 months on used whiskey oak at 65% ABV. The resulting spirit had a nice cola and molasses flavor but lacked the esters I enjoy (go figure) and it wasnt funky at all. So I added 3 quarts of this spirit, about 2 mL of concentrated sulfuric acid, and 1 quart of 8 month old muck (frozen in my shed for the last 4 months lol) to my air still.

My thinking was that the rum was already cut with no heads and no tails in it. So any esters produced in the distillation will be hopefully the desirable kind. That way I didn't have to cut heads during this run, and could keep the esters coming from the muck. I just had to cut tails to keep the nasty organic acids like vinegar out. I also had some copper scrap in the boiler to reduce sulfides.

I kept some funky tails that reminded me of grass, and a weird (clean) diaper smell. I also added the "foreshots" and "heads" even though they smelled like solvent and fake fruit. I was reluctant to add these, but I'm usually rewarded when I'm more aggressive with cuts than I think I should be.

The final spirit came out at 70% ABV and I recovered probably 75% of the volume of spirit I started with. It isn't nearly as funky as J. Wray and Nephew overproof, but it is smooooth. I could drink it at 70% if I was inclined to. It has a substantial caramel/molasses sweetness and still has the cola note it had before redistillation but with a crushed pineapple finish. Pretty nice, really. It's not as estery as I'd hoped but the molasses flavor was improved with the addition of pineapple and maybe some strawberry which I didn't detect before redistillation.

The pH of the stillage after the final run was about 3.5 so I could have added a bit more sulfuric acid, but I also was nervous about it. Concentrated sulfuric acid can be diluted by a factor of 1000 and have a pH around 1 so I proceeded carefully.

Anyway, let me know what your thoughts are. I don't drink much white rum so I probably won't do this again, but I'm glad I did it. It also taught me a little about rum distillation. For instance:

-A majority of the esters in a high ester rum must come from fermentation since redistilling clean aged rum with 25% live dunder didn't result in too many esters.

-Redistillation doesn't reset the clock for rum and make it taste unaged. It mostly just removes the color and maybe adds esters when done with live dunder in my experience.

-I think refluxed and oak aged rum with tight cuts and a clean fermentation is boring, hence my willingness to mess with it.

If anyone else has redistilled aged rum with muck, let me know what your results were.

Cheers,
Dokimos