Introduction
If you, as a craft distiller, want to make the best spirits possible, you need to have full control over all variables. If you want to make the beste spirits consistently, you need even more control. This iStill Blog post dives into the influence of dephlagmator induced taste variance, how it can screw up your run, and how iStill’s innovations help solve the issue.
The influence of a dephlagmator on distilling
A dephlagmator is a pre-condensor that sits high up in the column. When a beer or wine is brought to a boil, gasses rise up through the column. In a potstill, the gasses go up via the riser and then migrate horizontally via the line arm and then are bend downwards before entering the secondary or product cooler.
Dephlagmator: a partial heat exchanger ...
In a (traditionally plated) column a dephlagmator or dephlag is added near the top of the column or riser. The aim is for the dephlag to cool a certain percentage of the gasses back to liquid state. This liquid, called reflux, falls back down in the column and can be reprocessed by that column for further purification and concentration. For instance via bubble cap plates or perforated plates in that column, under the pre-condensing dephlag.
As a result of part of the gasses being cooled back to liquid phase - and them being redistilled lower in the column - rising gasses and reflux exchange molecules, making the reflux lower in ABV, while the gasses get a boost in alcohol percentage. When those now enriched gasses hit the dephlag again, another portion of them is turned into reflux, while another faction leaves - as gasses - the top of the column to be cooled down into spirits.
The dephlag is in use since the 1860's and is still in use on most column stills for its capability of creating reflux. Here is a schematic drawing (yes, by yours only) of how a dephlag works:
Dephlagmator: reflux vs. enriched gasses ...
How dephlag induced variance screws up your run
The dephlag is fed by gasses from the bottom and by cold cooling water from the side. The cold cooling water condenses (part) of the gasses. Near the top redistilled gasses leave the system, to meet-up with the secondary product cooler. Also near the top, now warmer cooling water exits the dephlag.
Even though dephlagmators do a good job at creating reflux, they come with a set of severe drawbacks. Drawbacks have to do with that dephlags run depending on cooling water. More water in means more cooling, more reflux, more purification, and less product. Less cooling water throughput means less reflux, less purification, and more product comes over per hour. But cooling water isn't a given. It, and a number of other variables, has certain properties that are vulnerable to variance. Here are the biggest confounders:
- How cold or warm is the cooling water to start with?
- At what water pressure does the coolant come over?
- What's the delta between the cooling water, the still, and the gasses?
A dephlag "controlled" column has a lot of variables to deal with. And each variable shows variance. Cooling water may be colder in the winter or in the morning, resulting in seasonal or temporal changes in cuts, flavors and ABV.
Water pressure may be lower early in the morning and later in the evening. Less water pressure means the dephlag doesn't cool so much during (at least) parts of the run, resulting in lower ABV hearts cut and more smearing of heads and tails.
How hot is your distilling hall? And how does that change over time? For sure the delta between the coolant, the still's outside and the gasses is important. And when it is constantly changing, so are your cuts, so are the flavors you bring over in your spirits!
When using a dephlagmator, the craft distiller will struggle to make a spirit the best way possible. And recreating the same drink over and over again becomes neigh impossible. In short?
Due to dephlag induced variance, you just screwed up your run …
The iStill solution to dephlag induced variance
Our mission statement is "Distilling made easy". And in order to help make distilling easier, it has been our goal to minimize dephlag induced cooling water variance. We succeeded. This paragraph explains how we did it.
iStills do not have a dephlag. Instead of a pre-condensor high up in the column, we placed a full-size condensor above the column. "Full-size" means ALL the gasses are cooled down to liquid phase. "Above the column" means just this: there is no U-tube with consecutive after cooler on top of the iStill condensor. All the gasses are cooled down to liquid and fall down to the collection plate system. It is at the collection plate system, with the help of the robot, that selections between "product out" (spirits) and "product back into the column" (reflux) are taken.
Since all gasses are cooled back to liquids, the iStill design has no variance at all. Cooling water temperature does not influence cuts or purity or ABV. Nor does water pressure (or changes in water pressure). Finally, delta's between column, distilling hall, and coolant don't play a role anymore either.
As long as there is enough coolant, the iStill creates a distilling environment free of dephlag induced cooling water issues related to temperature, pressure, and delta's! The innovative iStill column and condensor set-up allows you to make your drinks the best way possible. With the same cuts, ABV, and flavors ... each and every run.
This is how iStill's full-size column condensor works ...
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