Ive been reading the monster
flute talk thread on HD, trying to work out the best way to build a plated still. In order to understand the best way to design it, I want to understand the variables involved. Im not SURE about any of them, Im just posting my best guess. If you know better please let me know.
The variables associated with the still output are:
Distillate alcohol percentage
Distillate flavor
Output flow rate
Column Diameter: The wider the column, the more power it can handle, and faster the takeoff rate. No direct influence on % or flavor. For best results use at least 4"
Number of plates:This is the primary driver of alcohol %. From what I read, two plates will get you in the 60% ballpark, Mac and Crow suggest four plates for a good balance of flavor and strength (should get into the 90s)
Height between plates: The lower the height between plates, the more flavor carries over. Need to beware of smearing if they are too close together. Typical height seems to be around 4" (100mm)
Depth of distillate on plate (Height of downcomer above plate): I think that deeper distillate might get you better separation, as the vapor bubbles get better mixing on that level, possibly lowering flavor? Typical depth seems to be 3/4" (20mm)
Slotted bubble caps: makes small vapor bubbles. Probably same effect as deep distillate.
Smooth edged bubble caps raised from plate floor: makes larger vapor bubbles, opposite effect as deep distillate
Diameter of downcomer: The greater the diameter, the lower the likelihood of too much reflux overwhelming the plate. Helps handle more power. 3/4" seems to be the popular choice.
Diameter of upcomer: The smaller the upcomer, the faster the vapor moves through it. Not sure what effect it has overall as long as it isnt so small that the restriction slows your output.
Diameter of bubble cap: The bigger the cap the slower the vapor comes out possibly same effect as depth of distillate. Looks like for a single cap plate, a 1.5" cap is used.
Distillate surface area (the room on the plate not taken up with upcomers and bubble caps): Ive been thinking about this one. Vapor pressure is partly a function of surface area. I think if you maximise this, you will have faster output. One way to maximise might be to raise the distillate depth to completely cover the bubble cap.
These are all the variables I could think of. If you have other variables, or see something wrong with what I've said, please comment.