When we just started distilling at Rummieclub we were contacted by a supplier of frozen sugar cane juice. If we wanted to buy sugar cane juice to make rum. We never even considered the possibility because sugar cane juice is just too hard to get in the Netherlands. It also turned out to be 20 times as expensive than making rum from molasses. Too expensive for us at the time but we did decide to some day make a sugar cane juice rum.
Early November 2022 we were contacted by the same supplier, they had a batch in stock that neared the expiry date, if we were interested to take it off their hands for a nice discount. We immediately said yes.
A few days later a pallet full of boxes with bags of cane juice arrived. Because sugar cane juice ferments before you can say “yeast” it is only available deep frozen in the Netherlands. First thing we had to do is to thaw up 150 3-liter bags of juice. Because some of the bags were leaking it took us a day and most of the evening to thaw most of the bags and put them in the still. Our still is very well insulated, which usually is a good thing but now the cane juice slush turned into one big lump of ice inside the boiler. We had to wait another two days before we were able to turn on the agitator and the heating.
For the fermentation we decided to use our standard yeast. We also considered using a wild yeast. Wild yeasts are less predictable and usually have lower yields. Since the cane juice was quite expensive we didn’t want to risk being stuck with 500l of half fermented wash. Before we start the fermentation we always measure the sugar content because this shows us how much alcohol will be produced by the yeast. We use a unit called Specific Gravity, just water is 1.000. If there is more sugar in the solution, the density increases and so does the SG. This fermentation started with SG 1.084 (20.2 brix) which comes down to about 227 grams of sugar per litre.
We also chose for a relatively cold fermentation, 22°C. Our iStill can also ferment and control the temperature by either cooling or heating the wash. Usually sugar cane rum is made in the tropics because that is where the cane grows. The fermentations there are always a lot warmer. We are in the Netherlands so we wanted to know what a cooler fermented sugar cane rum would a taste like. Unfortunately, we needed the still for a contract distilling project before the fermentation was completed, so at the end we boosted the temperature for 48 hours to 28°C.
After the yeast ate (almost) all the sugar the SG was down to SG 1.031 and pH dropped to 3.9. With the difference in SG we calculated the alcohol content to be 7.07% abv. Now that the fermentation is complete we can start our distilling run.
Our iStill has a nice feature which is the pre-heat setting. You can tell the still to start heating the wash to 60°C in the morning. When we get to the distillery the still is already warmed up. We so have to manually start the actual distillation. We used ABV control in the distillation. This means that the still tries to keep the output a set alcohol percentage as long as it can. This feature enables is to use just one distillation to get high proof alcohol. In every batch distillation you have to make cuts, the fores, heads, hearts and tails. The hearts are the most important because they are the eventual product. We also re-use the heads and tails.
This is the overview of the distillation with all the cuts:
|Cut||Abv||Amount||Amount of 100% alc.|
We started with 500 litre of 7,07% wash. This contains 35,35l of pure alcohol. In this distillation we were able to extract 93% of all the alcohol that was made in the fermentation. Only 41% of total amount of alcohol made it into our bottles. The heads and tails were redistilled and are now part of a molasses based batch resting in one of our barrels. We are very curious how that will turn out.
We loved the project and the rum turned out great! The whole batch yielded 27 bottles of rum at 50,7% Abv and some extra in our store to taste. The taste is really funky with notes raspberry and of course the grassy notes that we all know from Rhum Agricole.