What's the real cost of deep-tail collection?

[indyspirits]

Ever since I was a distilling noob I've heard/read  "You dont want to collect lower than x% at the parrot because it's too expensive". The Distillers Guide to Rum says it well:

Quote

...Because even though there is till a little alcohol left in the boiler, the energy needed to extract what little remains is part the point of diminishing returns.

What data supports this?  What's cutoff makes the most financial sense?  If my condensed vapor (assuming simple pot still / no reflux /trays) is 9% the contents of the kettle is roughly 1% ABV.  If I have a 600 gallon kettle and I've vaporized 50% then I have roughly three gallons of etoh.  If I reclaimed 50% of that we're talking 3 proof gallons or 15ish bottle of product at 40%. Say I put those into the 3-tier at $14 / bottle that's $210 in revenue.  Our COGS is a about $5 per bottle (a figure is that much more art than science) so after all is said and done $150 in revenue. That's not exactly a glowing recommendation for collecting low into the tails!

But what if we collect low and add feints to next strip? Is it a financially sound decision then?

I suppose the question I'm asking is on a product-by-product basis how far into the tails are you collecting?

 

 

 

[bluefish_dist]

I have recently been having the same thoughts.  I was looking at what I had left after a vodka run.  It's quite a bit, but the still and the cuts both say there is nothing good left.  On a spirit run from low wines, I find I end with about 1.5% abv.  Vodka is higher, but I don't remember the exact number.  

Since I run a VM the takeoff rate is really slow at that point and I could be adding hours to get another 1/2 to 1 gallon of alcohol.  Not worth the time or the money.  I usually shut off when it drops to a little less than 1/2 gallon per hour.  It will slow down even more from that point on.  It will run 2.5 gal/hr or more with a fresh charge.  

[Silk City Distillers]

My 2 cents (per bottle).  I don't think you can address it in simple terms, there are too many factors to consider, especially the qualitative.  Given a single pass pot still run, recycling tails is going to yield more recoverable product than the same wash distilled on multiple plates/reflux would (assuming you are running the plated/reflux still to yield a higher % of product).  Likewise, I would imagine that early tails are likely to yield more recoverable product than late tails, late heads more recoverable product than early heads.  I'm not reducing simple etoh% recovery, and instead am using the word "product", because I don't believe the two are interchangeable.

On another forum, we were teasing a bit about the new myth of the "all feints run", "queens share" or whatever you'd like to call it.  I say teasing and myth, because it does work well if you are talking about recycling single pass pot still feints (still lots of recoverable product), but when you are talking about replicating this on a reflux/plated column, with concentrated feints (e.g. less recoverable product), you end up with something marginal, at best.  This was not a myth when pot distillation was the standard, but as plates and reflux have entered the mix and become commonplace, this old technique no longer yields something to be celebrated.

I suppose it breaks down to what your current product yield percentage is, and how far you can push recovery without impacting product quality.  Break open Excel, start recording the numbers, and start pushing the feints % higher, tracking product yield, trying to keep quality consistent.

We recycle, but the volume is small, about 10% on a proof gallon basis (of the wash charge) This was our sweet spot, any more didn't result in higher product yield.

Neutral spirits are another matter I think, with potentially higher recovery rates if you have enough plates.