The distillation process begins with the distiller filling up the still with the fermented material in preparation for distillation. When heat is applied and the distillation process begins there are various components that are produced as a by-product of the fermentation process which start to separate based on temperature.
One of the primary jobs of the distiller is to ensure the fermentation process completed successfully and of course to ensure from all those components that only the best of the best end up on your bottle.
1. THE CUTS
Just like when describing the general anatomy of a fish during a distillation we have the heads which is the first part of the distillation, the hearts which is the meaty and delicious part and the tails which are the last part before we reach water boiling temperatures.
The distillate is divided in three parts according to its components and its quality: the head, the heart and the tail.
2. RE-USING HEADS
In the manuscript California Wine and Brandy Maker, which is essentially a scanned copy of an interview between Elie Skofis and interviewer Ruth Teiser which was conducted in 1987, Ruth goes over the early years of Skofi's experience in the California wine and brandy industry.
Throughout the book, Skofis mentioned how Dr. Guymon's research work had a very important contribution in the brandy industry, among those on page 101.
Also, another very important research project -- which resulted in millions of dollars of savings to both the California brandy and grain alcohol industries -- was the recycling of the heads (aledehydes fractions) back the the alcohol fermentation so that up to 95% of the aldehydes disappeared in the fermentation.
I became involved with Dr. Guymon in this project when I was with Schenley. We utilized the high heads spirits by adding sweet juice. Which in turn was fermented with other distillery material. After the distillation, we had a clean spirit.
3. THE EXPERIMENT
Initially, when I read over this I was a bit curious to see what others were doing. Traditionally heads are either disposed of thus loss in revenue or re-added into the distillation cycle, which can produce off-flavors especially if you are trying to achieve a very clean spirit for bottling versus something that will barrel age. The research turned out not to be productive as truly no-one shares this type of information.
In addition, none of the above was what Skofis suggested so I decided to figure out how to get some sweet juice in the middle of August. Grapes are a few months away for Washington State, so that left me with apple juice (Washington State produces 65%+ of apples grown in the USA).
Apples are in abundance here, so I was able to locate a fruit processor and purchased 175 gallons of that sweet juice. It was a blend of Washington State apples – Red Delicious, Gala, Fuji, Granny Smith and Honey Crisp.
The juice arrived at the distillery and was pumped into a 275-gallon IBC tote. The total volume was 175 gallons of apple juice in which I added 16 gallons of heads, really nasty stuff that was collected over grape distillations for a total of 191 gallons. The juice was left for a day to settle and reach room temperature, yeast with a re-hydration nutrient was pitched and day two fermentation started.
The initial Brix for the juice came in at 12.5.
Skofis continued with saying
Previously, if we treated the heads with various chemical such as caustic or potassium permanganate to destroy the aldehydes, we got a redistilled spirit that was fishy or chocolate in aroma, and poor in quality. Overall, we lost approximately 1% of the original Proof Gallon (PG) input as high head distillate which was simply destroyed and not re-used.
Approximately 16 gallons of heads were added to the fresh sweet juice, prior to fermentation.
4. THE RESULTS
During my experiment, I concluded that the process that Skofis mentioned did indeed work, and it proved very successful. Once fermentation completed I had a hard cider that tasted and smelled like fresh apples, with no aftertaste of the bad stuff.
Distillation also confirmed the theory, as I was getting a perfect apple distillate during the hearts distillation, heads and tails were captured as would normally.
5. THE REGULATIONS
So the question of is this legal from a Federal perspective? The TTB has approved this aldehydes re-fermentation process in wine as part of CFR 27 24.183 and also mentioned in CFR 27 24.216 from those early results that Skofis and Dr. Guymon's along with requests from the grain and brandy industry, but its still not clear if this is allowed in a DSP, I've emailed the TTB but no answer yet, once I get a response back I will update with the results.
6. CONCLUSION AND NEXT STEPS
There are still pending questions around the percentage of aldehydes or when and how to add them into the fermentation to ensure that the fermentation will not stress, in my experiment it was just shy of 11% of aldehydes to the total volume of juice, but I expect that you can push this number up and or down and come up with a general formula that will work for both grain and fruit spirits.
The second question that comes to mind is when you read the CFRs linked above, is that they mention a bonded winery and not a distillery. As I mentioned above an email has been sent to the TTB but I haven't received an answer yet, with that feel free to follow up with the TTB about your distillery before proceeding.
I personally will continue using this method and continue pushing the limits on the percentage of aldehydes you can add to a fermentation, along with the experimentation of different fruits, when to introduce them during the fermentation and also fermentation stress along with after distillation conclusions based on the various techniques.