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Coriolis

Still is testing me - help!

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Hi all,

I'm in the middle of an install and set up  on 1000l Hoga still with a hybrid column that i bought second hand. To be honest, it's proving difficult to get results and after a few test runs I'm starting to get frustrated and could really do with some input from more experienced peers!

Basically, I'm having a lot of trouble with the ABV of the product. Running in pretty much pot still mode (just 2 plates, no dephleg) the distillate starts coming out around 84 ABV with a pot temp of 80 degrees C and  drops dramatically in about 10 minutes to 60 ABV. From there it settles down and proceeds pretty much as you'd expect a stripping run to with the ABV dropping gradually over a period of 6 hours or so. In other words, I go straight from foreshots to tails seemingly skipping the heads and  hearts phase entirely!

Here's some details that might help with the diagnosis:

Pot size - 1000l

Wash size - 700l (aprox 13% ABV)

Heat source - Steam coil (admittedly the boiler is a bit undersized so keeping steady heat is a bit of a challenge)

Column width 300mm (aprox 12in)

Pot has agitator and is insulated.

Plates aren't really plates like seive or bubble caps. They are more of a series of inverted copper dishes. To be honest I have my doubts about the design.

There is a spike in still head temp as the product abv drops. It is at 73 C when fores start appearing and shoots up to 90 within 10 minutes as the ABV plummets.

 

My next step is to remove all plates entirely to see if those plates are contributing to the problem but it's getting expensive running 700l of wash everytime just to test it.

 

Any ideas or thoughts are very welcome!

 

 

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Might be a dumb question, but if a stripping run, why do you care?  

Are you sure 13% ABV?  It sounds like you are starting the run with reflux building in the plates and eventually breaking through thus concentrating the heads and then ABV falls and your boil temp goes up pushing more water vapor and lowering your proof.   Why use any plates in a stripping run?  

Try no plates and a slower boil.

Just a guess.

 

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I am no expert on stills with column and plates but I would think a 12 inch diameter on a 1,000 litre pot is out of balance, too wide, but I could be wrong. Just putting it out there for comment by others.

When you say "getting expensive running 700 litres of wash" are you talking about the cost of the wash or cost of running the boiler. If it is the wash you are concerned about just pour the condensate back into the pot to run for your next test. I can't help on the cost of running the boiler unless you could convert it to run on used motor oil or fryer oil (as I do)

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If it's a stripping run, why engage any plates? Also, the plates won't work to their full potential if you're not using the dephlagmator to condense vapor to be trapped by the plates. Maybe a little bit at first because the column is cold, but definitely not their full potential. The ABV drop is pretty extreme from fores to the middle of the run, but nothing you're getting off a stripping run is really "hearts" quality/material, so don't worry about it. Is your final collection adding up? I say skip the plates and the deph and just scream it through there if it's a stripping run. If your yield isn't adding up, then something is off. 

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I'm guessing you can't bypass the plates but not running the deph will basically give you about one theoretical distillation. Based on a 13% wash ABV I would expect the hearts to come out at about 60% ABV. So I'm not sure I see anything wrong with your distillation. And as others have pointed out, if it's thee stripping run then you'll collect everything. There's no way to go from foreshots to tails and not collect all the main ethanol.

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15 hours ago, Patio29Dadio said:

Might be a dumb question, but if a stripping run, why do you care?  

Are you sure 13% ABV?  It sounds like you are starting the run with reflux building in the plates and eventually breaking through thus concentrating the heads and then ABV falls and your boil temp goes up pushing more water vapor and lowering your proof.   Why use any plates in a stripping run?  

Try no plates and a slower boil.

Just a guess.

 

It's more about figuring out what i can and can't do with the different configurations rather than a true stripping run. I wanted to see how it worked in pot still mode with just a bit of reflux from the plates. I get your point though - if I am using plates then it probably needs the dephleg as well. 

Next thing -  I'll do what I should of done in the first place....take all the plates out, run as pure pot and then start adding complexity/plates/dephleg into the mix.

Thanks for the thoughts.

 

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10 hours ago, PeteB said:

I am no expert on stills with column and plates but I would think a 12 inch diameter on a 1,000 litre pot is out of balance, too wide, but I could be wrong. Just putting it out there for comment by others.

When you say "getting expensive running 700 litres of wash" are you talking about the cost of the wash or cost of running the boiler. If it is the wash you are concerned about just pour the condensate back into the pot to run for your next test. I can't help on the cost of running the boiler unless you could convert it to run on used motor oil or fryer oil (as I do)

I am recycling the distillate for these test runs for sure. Paying for the power is another story!

 

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3 hours ago, glisade said:

I'm guessing you can't bypass the plates but not running the deph will basically give you about one theoretical distillation. Based on a 13% wash ABV I would expect the hearts to come out at about 60% ABV. So I'm not sure I see anything wrong with your distillation. And as others have pointed out, if it's thee stripping run then you'll collect everything. There's no way to go from foreshots to tails and not collect all the main ethanol.

I guess when you think about it like that it make sense. The analogy of skipping the hearts was more to describe the phenomenon rather than anything else.

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5 minutes ago, Coriolis said:

I am recycling the distillate for these test runs for sure. Paying for the power is another story!

 

One would hope that someone did their home work when designing the column. It's not particularly tall at 1m. Attached is a photo for reference.

20200220_184242.jpg

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It’s sounds kinda normal to me actually.  I run 16 plates but turn off the reflux during stripping and my low wines average around 40 abv, with takeoffs ranging from 80% at beginning to 10% at end.

 

I think what may be happening is the small amount of reflux works for a bit then the still just overpowers it and sends everything thru.  In these situations it may be helpful to watch your boiler temp to see where you are rather than your output ABV or column temps

 

my $.02. :)

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45 minutes ago, FijiSpirits said:

It’s sounds kinda normal to me actually.  I run 16 plates but turn off the reflux during stripping and my low wines average around 40 abv, with takeoffs ranging from 80% at beginning to 10% at end.

 

I think what may be happening is the small amount of reflux works for a bit then the still just overpowers it and sends everything thru.  In these situations it may be helpful to watch your boiler temp to see where you are rather than your output ABV or column temps

 

my $.02. :)

Copy that...it's a bit different to my smaller set up which is a bit more linear. Every day is a school day in this game!

 

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Your distillation doesn't appear out of the ordinary. As long as alcohol that went into the pot matches alcohol left in the pot and collected, the still is working as stills do and there operation of it should be looked at, but its okay you are new to this still it will take time!

 

Is it copper all the way through? If you've never had a Lyne arm and condenser made of all copper before keep the fucker clean! Rinse it out and citric bath it often for best results other wise you'll see sky blue in your heads and tails.

 

Is there anyway we could see a picture of the interior of the column? maybe through that window with some light shining through?

 

 

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