Rum Theories

[CaymanRumBaron]

I would like to start a new thread about my thoughts on rum, reaserch on rum, what I has seen commerical rum distilleries do and from what is sprinkled about on this forum.

To start, I would like to say I have tried several different recipes of rum (panela, brown sugar, molasses), recycled yeast, recycled dunder, used dunder with mold etc. I have also run a wash that have not cleared completely and found a thin layer of white, oily substance on top of the cooled dunder, which I reused. I have also tried several ingredients in aging my product. I know everyone says age for atleast a few weeks to a year but I have had excellent reviews (from someone than drinks Ron Zacapa 23, Cockspur, etc.) with a product that has only been sitting a few weeks on toasted oak chips, raisins, a dash of vanilla and some apple slices. That said, in order to work towards repeatability, towards creating a rum on par with the greats (Mount Gay in my mind is the pinnacle) and in the spirit of sharing our experiences and thoughts for the betterment of mankind (those that want to create a solid rum anyway), I present my theories on rum.

Creating The Rum Wash
First off, we all start with a wash. Here are my theories on what make a rum mash unique, which in my opinion, is the most difficult part of the process as most anyone can make cuts and blend to instruction. I am leaving out the type molasses purposely as they vary greatly in content/taste region to region. I make the assumption that all rum washs will contain some type of molasses. I also make the assumption the rum will developed through multiple generations.

Yeast
Most of us use distllers, bread, wine or beer yeast. I am not sure what species of yeast but I assume that most of them are some type of Saccharomyces strain, which is the most common species. Other brewing yeast include the Brettanomyces type, which is used for lambic style beers. For specifically rum, Rafael Arroyo recommends a strain of Schizosaccharomyces yeast. As far as I know, this yeast is not available retail and most commercial distilleries have developed a proprietry stain of this yeast either from a commerical source or from the wild yeast (Leblon Cachaca comes to mind). As far as recycling the yeast, the commerical distillers always have a culture growing in a medium nearly identical to the wash so it would not be neccessary to collect the yeast from the wash, which is what we would do in order to recycle.

Dunder
Dunder is critical to flavor profile in rum. From what i have seen, dunder must be allowed to develop some type of wild yeast and/or bacterial culture of Clostridium Saccharobutyricum in order to develop the heavier rum flavors as per Arroyo. While actively fermenting, the bacteria in the mash work in unison with the yeast strains to develop the rum flavors. Because alcohol is much more toxic to the bacteria than the yeast, that is why the distllers only aim for around 6-7 % in the wash. From what I understand, the wild yeast and bacteria from the dunder are overwhelmed by the more the faster growing mash yeast that is pitched and also because the pitched yeast can tolerate much more alcohol.

Stilling the Wash
Reading this forum, I found a thread that caught my attention. The process of letting the rum wash settle before charging the still was questioned because commercial rum producers would not have the time to let their wash settle before distilling so it might be beneficial to note that a rum wash might not neccesarily have to be crystal clear before running through your still. I have run a rum wash that had not fully settled and week later came back to a oil slick on my dunder. Are the rum oils Pugi raves about actually the lipids (oils) from the burst yeast?? Should we run the first wash with the yeast in it order to get a good backbone for the dunder at the expense of the quality of the distillate?? Could I just save the entire first batch of distillate and rerun with the second generation wash?? These are questions I intend to find out as I remember getting a especially good rum from the mash that used that oil slicked dunder not to mention a fast ferment.

Rum Cuts and Oils
Investigating rum oils, Rafael Arroyo mentioned that the rum was separated into four fractions as we usually do namely Foreshots > Heads > Hearts > Tails. Where we usually only keep the hearts cut to drink but for rum, Arroyo recommended adding a fifth cut between the hearts and tails and then combining the hearts and the tails, which contain the rum oils. Specifically, he mentioned collecting from 100 proof to 75 proof seperately (which contained undesirables) and then combining the distillate that followed, containing the rum oils, with the hearts cuts. He mentioned that the rum oils are more soluble in alcohol than in water, so alone, the rum oils may float to the top of the container but when combined with the hearts (high in alcohol) will dissolve. My theory here is that we would have to include some yeast in the boil to get a good supply of rum oils in the tails. I plan to test this as well as I must agree that at 30% or 60 proof, some of the best rum flavors are there.

I am looking for comments from the board about these theories and any experiences the members may have had. Hoping to spark some real indepth discussion around rum.