Reaching 15% alcohol in your fermentation

When I started my own distillery in Panama back in 2017, I made a few key decisions that have proven right. First, I decided to distill in traditional copper pot stills (there are more than 130 malt distilleries in Scotland using this humble piece of equipment for obvious good reasons). Second, even when that meant a higher cost, I decided to use fresh ex-bourbon barrels and limit reuse to a second time in order to get real wood influence and color without applying shortcuts to produce our aged rum. And third, unlike mainstream rums, I chose not to use molasses as a feedstock.

After careful considerations, I chose to ferment artisanal sugarcane syrup made by local small farmers instead of molasses. For those of you new to this seemingly fancy term, I will explain it. You possibly have heard the name “panela” (called “piloncillo”, “dulce” or “raspadura” depending on which country of Latin America you are in). It is a solid brown block of unrefined whole cane sugar derived from the boiling and evaporation of sugarcane juice, usually made by an artisanal producer.

Well, this syrup is the form the evaporated sugarcane juice takes just immediately before getting transformed into “panela”. ?It is a viscous brown liquid somewhere in the range of 70-75 brix and it resembles molasses, but unlike it, this syrup has a very pleasant smell and taste, and a lighter colour. Since it comes from pure sugarcane juice, it is around 66-72% sucrose, a tiny amount of glucose and fructose, and just 3-4% of non-sugar dissolved solids. This is a huge difference when compared to the 45-50% fermentable sugars in molasses and its normally high ash content (7-15%) and non-fermentable solids. One caveat for us though: given the syrup is artisanal and not a commodity, it is way more expensive.

Gosh! That was a long introduction, and I don’t want to get you bored. So, long story short, I knew I could be able to achieve a lot more than the 7-8% alcohol in fermentation seen in the traditional rum industry. I also knew the benefits of increasing the alcohol concentration in my wash. So, from September 2017 through March 2018, I conducted a lot of trials to see how far we could go. The resulting protocol we developed allows us to obtain 15% alcohol consistently and reap the benefits I describe to you below.

Energy savings

First, there is the savings in the amount of energy used for distilling. Without running the calculations, you might think that even when doubling the alcohol concentration of the wash, you still have mostly water and, consequently, a lot of energy is required boil it and distill it anyways. The boiling point difference of an 8% alc wash vs a 15% alc wash would not account for a significant energy requirement difference. Right? Wrong. The energy required to produce one liter of alcohol from an 8% alc wash is approximately 1.5 times that of the required to get one liter of alcohol from a 15% alc wash. That is about 35% reduction in energy needed per gallon of alcohol by going from 8 to 15%. Now, do the math with your own energy bill related to distillation and put some dollar signs next to it. Do you like what you see?

You could say, “Yeah, the energy required to produce one liter of alcohol is less, but I will be producing double the amount of alcohol which means that in the end I will also pay more!” You would be totally right, but again, please watch the landscape, not just the tree. I’m not going to get boring with all the math (I’ll leave that part to you), but to double your output of alcohol, you will only need 20-22% more energy than you have been using. How that sounds?

Less liquid waste

Just for the sake of simplification, imagine a continuous distillation system processing an 8% alc wash and producing a 96% abv distillate. This system has a stripper column that produces low wines at about 55% abv. Its operation will send to the drain (or wherever they send it to) 10 to 12 liters of stillage (vinasse) for every liter of anhydrous alcohol produced. When using a pot still, an 8% alc wash will yield something around 25-28% abv low wines. This means that the vinasse to alcohol ratio would be around 8-9 liters per laa. Now, if you increase your alcohol concentration in your wash up to 15%, that ratio would be only 4-4.5 liters of vinasse per liter of anhydrous alcohol (I encourage you to do the math).

Productivity and equipment capacity

My last point becomes more evident after the discussion above. When you double the alcohol content in your wash, you are doubling your alcohol output as well. And no, it won’t take more time. Distillation times will be pretty similar. You'll just have a bigger flow rate. So, you will be basically producing twice as much spirit in the same amount of time without having to invest in more equipment. Well, maybe not exactly. You could have to buy more tanks to store the additional spirit or invest in a bigger warehouse since you will be getting more barrels filled per day out the door. A good problem to have, I guess.

Now, a note about quality. I knew you were going to ask.

Are you concerned about the negative impact on flavor? You shouldn’t be. It’s a myth that by increasing the alcohol concentration in your wash you will get off notes in your spirit. I hate to say it, but if you do, there’s something wrong in your distillation protocol.

I like to compare the fermentation process to the color palette of a talented painter. It’s during fermentation that you produce all the beautiful congeners (colors) that you need to produce a nice complex distillate (your painting). You will need all the colors in your palette (the fermenter) to be able to craft something great. If you don’t have them, forget about a complex spirit. It’s the distillation process that will dictate how your piece of art will taste like. If you conduct your fermentation taking good care of your yeast, everything should be fine even at 15% alcohol concentration. Of course, it takes a few careful steps and planning: select the right yeast strain, take care of nutrition, manage the temperature stress in fermentation, implement the right distillation protocol, and voila, you will be reaping the benefits described above, just like we have been at Panama Craft Spirits.

Now, remember I am discussing sugarcane syrup. Can this be replicated with other feedstocks? To some extent, yes. Every raw material needs its own protocol, though. I have achieved good figures working as a consultant with craft distillers using grains, agave syrup, and a blend of raw sugar and molasses. Can you obtain similar results with molasses alone? Well, I guess the short answer is no. But you definitely can get much more than the 7-8% you have been considering as the standard all these years.

If you have questions on how to achieve 13-15% alcohol in your fermentation, don’t hesitate to get in touch with me.