2" VM Build

[Yarns]

Morning all,

So Hick1960 fixed me up with an excellent copper coil (Big thanks to Hick, what a legend) and has set me further along the path of being able to convert my FSD Pot to a still capable of reflux.

I have been doing some looking into a VM setup (no manufacturing, nice and modular). There seems to be some conflicting info on the size of the gate valve. I was planning on keeping it all 2". Some things I've read claim the 2" gate valve might be too big, were others say its just down to a cost (go as big as you can afford). I figure the opening of the valve will determine the amount of vapour heading to the PC anyway.

The only argument is can see is the decrease in fine control as the overall opening is much larger? IE 1/2 turn on a 2" same as full turn on 1" = less overall fine control.

If the cost difference is only in the realms of $20 is it better to get the larger?

Is the 2" valve to big? or will it just be down to how far I open it?

If (big if) I upgrade to a 4" column on a keg/milk tin boiler in the future. A 3/4" valve is no longer serviceable and I have the 2" valve still?

Before anyone asks why I bought a Pot if Im asking bout reflux. I have 6 buckets of grain in the garage about to turn into my first attempt at BWKO (for me). The wife as it turns out is more interested in this than I first anticipated and she would like to see what I can do for some vodka and other tried and proven neutral recipes (Espresso Vodka etc) I have showed her from the site.

If I can impress her, It might just result in more support down the line for a fancy Plater...

Yarns.

[RC Al]

The size of the valve will determine the lowest reflux ratio you can run
Ie a 2" valve on a 2" column will allow a reflux ratio (RR) of one to one, that is an equal amount of vapour will go to be reflux in the RC as would go to the the product condenser to be drawn off as product, this is as fast as a vm can go (without getting funky with an larger than column take off section)

This is more or less the figure to shoot for if you have enough power, boiler capacity and packed column height (40-60" for a 2"). If any of these are lacking, then a smaller valve won't hurt as you need to run more reflux to make up for whatever is deficient.

I see a common mistake of forgetting to size the valve by area, not diameter. If you put a 1" valve on a 2" the min RR is not 2:1, it's closer to 3.5:1. A 1.5" would be 1.6:1.

Dose all this matter? Sure, if your valve is too small, you will have a slow take off rate. If you put that 1" valve on a 48" tall 2" column with say 2000w of power, you will be sitting on about 600ml an hour take off rate, the 1.5" valve would allow a take off rate around 2.2l an hour, which would be about spot on for the average user (smearing comes into play), the 2" valve would be of use with more height and optimal packing distribution.

Edit, you can cheat and reduce the column down where the valve is...

[Yarns]

Thank you for the thorough response RC.

It sounds like going with a 2" valve give me the most adjustability down to theoretical 1:1. From you explanation and my reading, the 1:1 is at wide open. opening the valve just a crack should allow me to hold higher RRs as desired.

Quoted below from homedistiller.org, DestructoMutt had done some experiments with takeoff path reduction. From his findings, it was not necessarily the valve that limited the flow and therefore the min RR. It was that the smallest restriction in the takeoff path was the limiting factor. Which makes sense really, his purpose I believe was to disprove people saying that the reduction size of a leiberg condenser after the valve was inconsequential. These findings align with your edit about a reducer to the takeoff.

Also his findings in the first table would put your estimate for a 1.5" (2200ml) valve right on the money I would think.

Product condensor and valve match the take-off port size.
Take-Off Port Diameter:......... 2"....................... 1"....................... ½"
RR (theoretical*):................. 1:1..................... 4:1..................... 16:1
Product output:................... 2894ml................1139ml.................. 335ml
RR, observed**.................... 0.93:1................3.26:1....................15.89:1


Valve matches the take-off port size, product condensor is ½" diameter, reduction occurs after 90deg. elbow.
Take-Off Port Diameter:......... 2"....................... 1"....................... ½"
RR (theoretical*):................. 1:1..................... 4:1..................... 16:1
Product output:.................... 345ml.................. 334ml.................. 340ml
RR, observed**.................... 15.37:1................ 15.98:1................ 15.65:1


Valve matches condensor size (½" diamter), reduction occurs immediately after take-off port.
Take-Off Port Diameter:......... 2"......................1"........................ ½"
RR (theoretical*):................. 1:1..................... 4:1..................... 16:1
Product output:....................344ml.................. 337ml.................. 336ml
RR, observed**.....................15.97:1................ 15.77:1................ 15.84:1

Credit to DestructoMutt

Ill be using my FSD pot shotgun as my PC. Without working out the exact surface area, my guess (measure it when I get home) would be around 25-30% of the surface area available to vapour. So really in practice ill be held above the 1:1 that the valve will be theoretically capable of.

Yarns.

[Yarns]

Notes on my first VM spirit run

1m packed column. 500mm copper and 500mm stainless steel scrubbies.
Low wines consisted of stripped FFV. Resulting in 20l at 40%. Each strip (5 in total) discarded 250ml of fores before collecting down to around 20%.
I Followed KiwiStiller’s VM guide.

• Treated the low wines with Sodium Carbonate.
  
• Brought to the boil @2400w
  
• Let the column equalize @500w for an hour.
  
• Removed 250ml @2 drips per second as fores. 1.25 turns of the gate valve. Power @500w. Tossed
  
• Close gate 10m equalize @1900w
  
• Pulled another 250ml early heads at the same rate as the fores. 1.5 turns. 1900w. Tossed
  
• Close gate 10m equalize @1900w.
  
• Started 250ml cuts jars at a rate just over 1.5ltr/h (1.62ltr/hour based on math). 2.5 turns on the gate valve. 1900w.
  
• Temp stabilized @75.6
  
• Tested ABV periodically, the alcoholmeter consistently read 93%. Temp corrected +2.3% according to my alcoholmeter gives me approx. 95.3 ABV (+2.5% for distillate @10C. My distillate was at 11.5-12C).
  
• Everything was steady till Jar 18. Temp stayed .2 higher. Wound the gate back ¼ turn which dropped the temp back to 75.5-6. Rate dropped slightly as a result.
  
• Temp rose again ½ way through jar 21 wound back another ¼ turn. Temp returned to 75.6 again.
  
• Jar 26 ABV dropped. Corrected to 95%. Probably just margin of error.
  
• Jar 27 still holding temp @75.6.
  
• Jar 30 started tasting a bit off. Checked the temp. Sure enough 75.8. Wound the gate back another ¼ turn. Temp corrected back to 75.6
  
• Jar 31 still tasted funky even though the temp held @75.6.

At 31 jars. I had collected close to the hypothetical volume. Between that, the taste and it was getting late, I called it a night.
Jars are currently airing under a folded cheese cloth for cutting tomorrow night.

[Yarns]

I should have said, any thoughts are welcome. This is my first run.

I stuck my nose over a jar that I believe is somewhere in the hearts this morning. could barely smell anything. I was aware of my smell and taste was getting fatigued towards the end of the day yesterday. I was tasting periodically, proofing down to approx 40% 5ml (2ml distillate, 3ml water) total each taste, spitting each time. Not a time to get impaired while running a still.

[BigRig]

Sounds like you had a good run and are enjoying the new rig, with more use you will be able to fine tune everything further. Thats the job of the hobby (plus the drinking).

Its surprising how much the smell / tas dissipates with some airing.

[Yarns]

So a busy night of tasting last night. I ended up keeping jars 8 - 27 of a possible 31.

There was a very harsh transition from jars 7 - 8. I was really surprised. The tails end was a little harder. I was tempted to keep jar 28 but in the end decided to air on the side of caution.

Still very new to this and couldnt really discern the smells and tastes often talked about here. I just simply went off of if I liked the taste or not. I spat the tastes till the very end. With fresh water to rinse. When I decided on the jars to keep, I drank a 10ml taste of jars 8 and 27 just to make sure.

All blended, I ended up with 5lt at a temp corrected 95%. Still tastes a little harsh, the demijohn is currently airing with a small glass over the neck of the bottle. Might be able to air a bit more off.

I proofed down two 700ml bottles and have them in the liquor cabinet with the lids off. Giving them till the weekend to marry a little better (probably not lids off the entire time).

All in all not too bad for my first run. Wont be fooling any professionals. To me its passable.

The aim is to be able to distill a neutral that does not require filtering. Is it worth looking into for this batch?

An improvement I can already think of is another 300-400mm 2" packed section to give me 1300-1400 instead of the 1000mm currently.

[Yarns]

With some additional airing and much smelling and tasting of the proofed down bottles. I am not convinced that the neutral I produced is acceptable. It isnt particularly clean tasting and still carries a harshness to it.

I wasnt deliberately greedy with the cuts. I genuinely only included what I thought was ok. I dont know if I have the time this weekend. But I will be dropping all 5lt back in the still with about 7lt of water to bring it down to 40%.

Changes ill make is:

• Reconfiguring my sections to give me 1200mm of packed over the 1000mm it is currently.
• Running at the same 1900w but reducing the rate to approx 1lt/hour.
• Only include the previous "hearts" cut

Questions:

• Should I treat with Sodium Carbonate again?
• Should I dilute the 'low wines' with spring water? I live in the ACT and the tap water is quite good as far as I know.