Nanodistilling

We ended up with a very stubborn fermentation of 40 gallons of strawberry pressings. The first two fermentations got “stuck”, despite good yeast, sufficient yeast nutrient and temperature control. A third attempt with a special White Labs yeast got it running slowly, the the batch measured about 9% alcohol using a simple distillation yield test. The problem was the odor and taste was poor. We suspected acrolein as the defect.

In an attempt to try to salvage the alcohol, we employed an automatic fraction collector. We ran 15L through our LeFevre apparatus, which usually “cleans up” any wash and gives an excellent tasting distillate. The difference this time is that we replaced the receiver with a conduit to a Dynamax FC-1 fraction collector. This unit came from a preparative LC system we had, and has 26 collection wells. After observing a 2ml/min distillate takeoff rate, we set the fraction collector to advance every 30 minutes during the run. This would give us 26 samples of about 60-70mL throughout the distillation to observe for taste and odor. Our hope was to find a point in the distillation where the defect disappeared. We took 300mL from the run for foreshots, and then started the collection into 150mL glass tubes.

Unfortunately for us, the defect existed in all samples and we rejected the batch. We will do a GC-MS analysis on the samples to find out precisely what happened, but it seems that contamination from reopening the drum to repitch the yeasts caused the acrolein formation.

The fraction collector worked very well, and we HIGHLY ENCOURAGE you to try one if you have one or see one surplus. It is a fantastic way to observe what is happening throughout your distillation run without the labor costs of an operator.