Sudden Drop in Vodka Proof/Slight Cloudiness

[mvierth]

Hey, everybody! Quick question to ponder (and any help is appreciated):

We've been running a 18-plate Crystal Dragon StillDragon with 100 gallon kettle for our vodka/NGS production. We've had this setup since August of last year and have been able to consistently hit 95.625% ABV on each of our 100% wheat low wine runs. However, the past two days, for some reason, we're struggling to even hit 95% ABV. 

Here's our basic rundown: 

1. 500 Gallon, 100% wheat mash typically at 1.088 SG. Fermentation to 1.000. 
2. Stripped to approx. 125 gallons of low wines at 36% ABV. 
3. Proofed down to 25% ABV with tap water then fed into the kettle. 
4. Full reflux for one hour, then slowly exiting reflux into heads. 

This typically gets us to 95.5% ABV by the time we hit hearts (about an hour into distillation). 

However, these past two runs, we've done the exact same thing we've always done. The temperature of the kettle is the same, amount of water and temp of dephleg is the same. The only thing that's changed is the proof is struggling to get over 94.5 and there's a slight cloudiness in the final distillate. 

Any help is greatly appreciated! 

[bluefish_dist]

In my testing I found that low abv was one of two things, not enough reflux or not enough column height/plates.  Once the still was tall enough it could run from wash or low wines and still hit the same abv.  If the takeoff was too fast then abv would drop.   With 18 plates you should have enough height, although another few would help.   I would think reflux rate would be critical due to the plate count.  If it's a little low it would be off.

you might have a leak in the deflag?   Even a tiny amount of water would lower the proof   Might also be the reason for the clouding.   I would do a pressure test and make sure it doesn't leak   

Do you monitor the temperature at the still head?   I find this is a good indicator if something is off.  Although it does change with the weather.   I take an abv reading right away to make sure I am at 191, then hold that temp until it hits tails.  

[mvierth]

Hey, Bluefish! Thanks for the feedback. 

It's looking like it may be a leak in the dephpleg. Reflux has been steady and there hasn't been any sort of indicator other than the sudden drop of proof.  

Next step is pressure testing. Thanks so much for the help! 

[mvierth]

 

Some more perspective: After exiting reflux it will hold steady at 190.5 for about half an hour. After that, with nothing being tweaked, the proof starts creeping downwards. Another sign of a leaking dephlegmator? 

[Roger]

Try shutting the defleg water off quickly and completely after 45min or so of column to equalization. This will blast the heads out and keep them from smearing. Then go full defleg again for 15 mins or so, then bleed into the hearts. 

 

[bluefish_dist]

If the abv drops over time, could be you need to up the reflux.   Watching head temp will give you a warning that it's happening.  Even .1 deg is enough  that you might need more reflux.  

I found that on my still if reflux is more than enough it will hold abv for a long time without adjustment.  If it's at the ragged edge of enough, any change in boiler abv requires a adjustment to reflux/takeoff rate.   I run a VM, so it's a little different than they typical deflag setup.   For me I might run say 8 turns open on the takeoff.  That will hold abv all the way until tails.  If I start the run at 12 turns open, then I will have to adjust every 30 min by 1/2 turn to hold 191.  Pretty soon the valve will be closed down to 8 turns.   The take off rate doesn't get much faster even though the valve is more open, so I prefer to run slower at the beginning to make it less stressful to run.  

[captnKB]

are you correcting your proof measurement for temperature? Changes in the temp of the distillate by a few degrees may be skewing your reading at the paarot

[mvierth]

SOLVED - We did end up having a leak in our condenser. Thanks for everyone's feedback! 

[mvierth]

Also - Sincere shoutout to StillDragon. Once we let them know our condenser was leaking they shipped a new one out immediately!

[Silk City Distillers]

Larry and crew at SD are good people.

[ChrisSD]

Thanks @Silk City Distillers.  @mvierth we apologize for the issue but we're happy we could resolve it quickly.  We do pressure test them in house, but not with different temp swings in play.  Either way, we pride ourselves on offering great customer service, so if anyone has issues, please don't hesitate to reach out to us!!

[PROOF]

On 1/22/2018 at 2:16 PM, mvierth said:

Hey, everybody! Quick question to ponder (and any help is appreciated):

We've been running a 18-plate Crystal Dragon StillDragon with 100 gallon kettle for our vodka/NGS production. We've had this setup since August of last year and have been able to consistently hit 95.625% ABV on each of our 100% wheat low wine runs. However, the past two days, for some reason, we're struggling to even hit 95% ABV. 

Here's our basic rundown: 

1. 500 Gallon, 100% wheat mash typically at 1.088 SG. Fermentation to 1.000. 
2. Stripped to approx. 125 gallons of low wines at 36% ABV. 
3. Proofed down to 25% ABV with tap water then fed into the kettle. 
4. Full reflux for one hour, then slowly exiting reflux into heads. 

This typically gets us to 95.5% ABV by the time we hit hearts (about an hour into distillation). 

However, these past two runs, we've done the exact same thing we've always done. The temperature of the kettle is the same, amount of water and temp of dephleg is the same. The only thing that's changed is the proof is struggling to get over 94.5 and there's a slight cloudiness in the final distillate. 

Any help is greatly appreciated! 

i wonder if it is the tap water and something coming over in the distillation from it. we use ro water for ours.