StillSmart

Well hello from a forum noob! Not a distilling noob, but certainly a building my own still noob!
Thats my noob status sorted out, and as all noobs of all statuses I have questions! I did search, but didnt find the answer in plain enough english for my tiny brain.
I'm building a reflux still, 1200 mm tall in 54mm copper, it will basically be a larger copy of the one i have been using for the past 8 years, so should work ok. My question is about controlling the boiler. Im going to use a 30litre tea urn and wonder if i thought right about controlling it.
Heres the plan: take out the original thermostat, wire in a voltage controller, which will be powered via a temperature sensor with a built in power controller. The temp sensor will be inside the tower at the level of the exit pipe into the condenser and set to 78 degrees.
So the temp sensor turns the mains power to the voltage controller to keep a constant 78 degrees at the top of the tower, and the voltage controler will be set at Xvolts.
The question is, how many volts is X? And do i even need the voltage controler? Will 2000watts of heat damage my wash? And is the top of the tower the right place for the temp sensor?
Any advice appreciated, cheers!
Charley

Hi FyIsprit

Quite a few questions there, I get your idea, but I don't think it'll work like you imagine it, regarding power, 2000W will be fine for a 30lt boiler, you won't damage your wash and you'll only use that much during heat up, or on a stripping run, during a spirit run you'll need much less power.

Perhaps more important is the stability of the power, it needs to be continuous for the reflux column to be balanced and work most efficiently, switching the power on/off won't work, the column needs a constant flow of vapour rising and reflux return liquid flowing back down I order for it to work, if these are not stable the reflux ratio will be changing all the time and the output spirit will be similarly changing in quality and ABV.

Trying to control the power with the output vapour temperature is too tricky, firstly the temperature will never be at 78°c you'll probably find it will stabilise around 82ish, for example it may start producing heads at 81.8°c - 81.9°c and then settle to 82°for the majority of the run, an increase as small as 0.2°c over the time it's running, which could be several hours, would indicate tails are coming and be the end of the run.

The temperature of the liquid in the boiler will rise throughout the hole run but the output from a reflux column will change very little.

I use a power controller connected directly to the element and a cheap, plug in power meter to see how many watts I'm using.

What type of reflux column are you building? Im assuming you'll have a cooling coil at the top, but is the takeoff and control LM or is it VM?

@Fylsprit: The only temp I work with is that at the head nof the column. Make my cuts based on it. All other temps are irrelevant.

Anavrin and rum John, thank you!
Anavrin, your reply has thrown up even more questions, which I will ask when I have a bit more time, but thanks again.

Hi Anavrin,
Ok, good to know i wont damage the wash with 2000 watts.

Anavrin wrote:
Perhaps more important is the stability of the power, it needs to be continuous for the reflux column to be balanced and work most efficiently, switching the power on/off won't work, the column needs a constant flow of vapour rising and reflux return liquid flowing back down I order for it to work, if these are not stable the reflux ratio will be changing all the time and the output spirit will be similarly changing in quality and ABV.

The experience i have of a similar device was that it in effect ended up cycling the power on and off about 30 times a minute, so i wonder if the net effect for the column is just the same as a lower power? But then i read what you said about the temp in the column, is it self regulating? If i set the power input to produce 82 degrees at the top of the column, can i just go and leave it knowing it wont get stupidly hot towards the end of the run?
And am i wrong in thinking the temperature at the top of the column should ideally be 78 degrees?
I'm afraid i don't understand your question about what sort of still it will be. What does LM and VM mean? The design will be a column about 120cm tall and a condenser about 50 cm tall with the cooling water inflow and outflow passing through the column at the same height they go into and out of the condenser .or is that bonkers? Maybe its better to have the cooling water take a couple of turns through the column before it even enters the condenser, then not at all at the top?
I really am appreciative of your answers, thank you for taking the time!
Regards

In theory ethanol boils at 78.15°c so in an ideal world, that would be what you measure, however this is real life, the temperature probe will be mounted somehow in the side of the column, it will read a few degrees higher, exactly how much will depend on you still, and everyone's is different.

It's important to realise you can't adjust the power to set a temperature, the liquid in the boiler will have a boiling point, this will depend on its composition, it's amount of alcohol and water, throwing more power at it won't make it boil at a higher temperature it will just produce more vapour, if you use too much power, some of the heavier elements like fusel oils will also enter the vapour stream, these oils are tails and you dont want them in your collection.

The trick is to use just enough power to boil the wash to produce some vapour that can be condensed and collected as spirit.

When the wash is boiling and the cooling is on full with no product being collected, the still is operating at 100% reflux, ie all the vapour is being cooled to liquid and is flowing back down the column, the action of vapour rising though a packed coulnm and liquid returning down the column is how the magic works, as the two pass in opposite directions the liquid in the vapour condenses in the liquid returning, and so doing increases the alcohol content left in the vapour, this will happen many times in a packed column until the vapour is almost pure alcohol.

How you collect the alcohol, and the speed you collect it determin the quality of the spirit, and at the same time how the stills operation is managed, the two most common ways LM and VM, but there's also CM

LM is liquid management, you have a slant plate or similar under you cooling coil the collects the liquid, and from that you can opens a valve and collect the liquid.

VM is vapour managment, with this you have a outlet from the side of the stills main column to a large valve, as you open the valve you control how much vapour exits to the condensor

CM is cooling management, with this method, the outlet is above the cooling coil, and by adjusting the flow of cooling water in the coil, you allow some vapour to pass though the coil into the condensor.

They all have pros and cons, far too complicated to expain at this time of night, but with all the methods, the more you try to collect, the less liquid there is to flow back down the column to maintain the reflux in the column, less reflux equals a lower ABV spirit, so it's always a balancing act, for a 2" column, on a spirit run, a collection rate of 1-1.2 litres an hour should be achievable while still keeping the % ABV over 90%

Thank you anavrin!
Well I guess a voltage controller it is then.
As far as cm lm and VM goes, VM sounds as though you'd have a pressure buildup in the column as you're controlling how much vapour escapes, or have I misunderstood? Anyway, sounds a bit dangerous! I'm leaning towards lm in that case as cm must surely rely on constant water pressure, which I know I won't have. With lm I guess you can just crank up the water flow as you want everything to condense at the top of the column regardless. So in an lm column is the top open to the air? If your condenser is efficient enough no vapour should escape, right?
Thanks again for the info.

Fylsprit wrote:Thank you anavrin!
Well I guess a voltage controller it is then.
As far as cm lm and VM goes, VM sounds as though you'd have a pressure buildup in the column as you're controlling how much vapour escapes, or have I misunderstood? Anyway, sounds a bit dangerous! I'm leaning towards lm in that case as cm must surely rely on constant water pressure, which I know I won't have. With lm I guess you can just crank up the water flow as you want everything to condense at the top of the column regardless. So in an lm column is the top open to the air? If your condenser is efficient enough no vapour should escape, right?
Thanks again for the info.

They're all fine, with no inherent dangers.

Many of the frequently mentioned ones like my T500 are CM, and while it took me a while to suss what was going on, if you're using mains pressure supply directly to the adjustment needle valve, you find that tiny changes in the valve can indeed produce quite pronounced temperature swings (I was getting nearly 5 degrees C changes, even when the bog was flushed).

Easily remedied, by putting a caravan water pressure control valve in line before the needle valve.......

Ergo, it's pretty much personal choice on design - within the usual operating parameters of course, and how strong you want to be able to produce your spirit, and what kind of spirits you're making........

Nicely explained Anavarin,and a nice follow up by Phantom.
Both posts answering questions and yet still leaving a new distiller with more questions to answer themselves,regarding the product that they wish to produce,the quantity,the speed and the strength,the taste.
Home builders may have a few more questions,but I firmly believe that if you can build one still,you can build any still.
The design may not be your forte,but if you can join pieces of pipe together,enough members here happily share their builds.
Or the commercially available options may suit.
Just do it!
If you have read this far into this craft,then low cost,high quality alcohol becomes your right.
Claim it.
OK,time to stop telling people what to do...

Robert.

Thanks Phantom and Easydrinker.
I'm definitely going to make it a LM then, am I right in thinking the top of the column is open to the atmosphere?
I was thinking of using marbles as packing, I've seen you can buy ceramic rings or even stainless spirals, but marbles are a whole lot cheaper. The question is, how much difference does the packing make? And how high up the column should the packing come?

HI Fylsprit

I don't think anyone uses marbles anymore but I may be mistaken.

I have both 6mm ceramic raschig rings and stainless steel pan scrubbers available, I find the pan scrubbers work best and they're cheap, you can get 6 for a £1, you just need to make sure it really is stainless, some very cheap ones are only coated to look shiny, best test is to use one for a week in the kitchen sink, then see if it rusts or not.

If you can get SPP, Spiral Prismatic Packing, I would say go for it, it's expensive but very good, first developed and tested by vodka loving Russians.

I'm hoping to get some for Christmas :-)

And yes, both LM and VM are open at the top of the column, CM is also open, through the product condenser.

About a meter of packing should be plenty, if you can get SPP you could go shorter but a meter is a good starting point.

Thank you! Pot scrubbers it is then, trying to keep the cost down! I'll be sure to test them as you suggest. I'll post pics when I get underway with it.

Have a look around. Rather than pot scrubbers (which you have to check to make sure they're stainless) you can get rolls of copper mesh packing......

I use a T500, so also would like some SPP, but you can get the rashig rings cheaply enough (which I prefer)......

Hi Phantom, yeah, I saw the copper mesh, I was just worried it would be difficult to pack it properly. Pot scrubbers you'd just need to smooth down the column on top of each other.
Where have you seen raschig rings at a reasonable price? Cheapest I've seen is £20 for a litre I think.
Cheers