Distilling Rum (Journey Into Rum Part 4)

This is the fourth post documenting our journey distilling rum at the Shakespeare Distillery. The molasses wash that we prepared the last time actively fermented for one week. The final gravity (which is a measure of the specific gravity at the end of fermentation) came to 1.007. It appeared to be stable at this gravity which meant that the fermentation was complete and the fermentable sugars had been converted into alcohol.

Distilling Rum on the Alembic Still

I took a small sample of the 7%abv molasses wash and did a mini distillation in a copper alembic still. Then I divided the wash between three stills to make sure the distillations ran quickly. The low wines were collected (weak liquor produced by the first distillation of wash or the first run of the still) until the distillate coming out was around 7% abv, at which point I stopped collection. We stopped at this point because David said the taste wouldn’t be good anymore. He also said that he had done some research online where someone said that after this point it is no longer economical to keep collecting distillate.

I combined the low wines together and recorded the volume and %abv. Then I performed a second distillation with the low wines and collected the distillate in 20mL fractions so that we could taste each fraction in the run to determine where our cut points should be made.

I collected 21 fractions in total. We had a group taste test and decided to keep fractions 2-19 and discard the other fractions.

Distilling Rum on the iStill

Next, we moved on to our large-scale distillations. We had around 1600L of molasses wash, but the capacity of the iStill was 500L, so we had to distil the wash in four batches. During the first large-scale fermentation, the distillate smelled burnt and plasticky which gave the entire room an intense fart smell.

The distillate coming off the iStill was completely different from the distillate that came off of the small-scale alembic stills. I was quite worried at this point, since the iStill was advertised as being able to distil a delicious rum after only one distillation.

After distilling all 1600L of wash, we were left with 280L of low wines at 40%abv. We charged the still with the low wines and did a second distillation. We collected 130L at 74%abv during this second run. I took a sample of the white rum and diluted it down to 40%abv with reverse osmosis water. I let the rum sit for a couple of days and then we had another group tasting. The white rum was enjoyable, it was fruity on the nose and paired well with the Coca-Cola.

However, our expectation was that we would only have to do one distillation of the molasses wash, so we contacted iStill and asked them for advice on fixing the terrible smells and flavours that were coming from our initial distillation run. They suggested that it might be due to solids in the wash getting burnt on the heating elements of the iStill, so next time we will rack off some of the dead yeast in the fermenter and also use a lower temperature on the iStill to minimize the amount of solids being burnt onto the heating elements.

Watch it Below on YouTube

Related Content:

• Making Rum with Molasses (Journey Into Rum Part 6)