Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
Improved bucket still - how it works
http://www.stillcooker.com/improved-bucket-still.php
Here is a link that has been floating around for a while. Its a link to a still utilizing two buckets placed into each other. There is an immersion
heater of sorts that is placed in the bottom bucket, containing the mash. As the mash heats, the alcohol vapor rises and condenses on the lid of the
bucket, and drips down into the second bucket.
My question is this - what makes the alcohol concentration 35-40% when heated at 45c-52c?
also, where could one find this type of heater? -- what else would work if nothing can be found?
|
|
|
B(a)P
International Hazard
Posts: 1114
Registered: 29-9-2019
Member Is Offline
Mood: Festive
|
|
I imagine it only comes across at such low concentration as it has effectively zero column length to separate water from alcohol in the vapour phase.
If I were trying to reproduce that set up in the link you provided I would use the element from an old kettle and a thermostat.
If you are going to do it this crudely then use what you already have. Use your biggest cooking pot with a bowl that fits inside. Put the pots lid on
up side down if it is convex and put some ice in the upturned lid then heat it on the stove top.
|
|
|
Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
Quote: Originally posted by B(a)P  | I imagine it only comes across at such low concentration as it has effectively zero column length to separate water from alcohol in the vapour phase.
If I were trying to reproduce that set up in the link you provided I would use the element from an old kettle and a thermostat.
If you are going to do it this crudely then use what you already have. Use your biggest cooking pot with a bowl that fits inside. Put the pots lid on
up side down if it is convex and put some ice in the upturned lid then heat it on the stove top. |
I appreciate the feed back.
What kind of thermostat? Do you have a link?
I don't think the stove idea will work, though I've seen it mentioned before. As the alcohol evaporates and the mash reduces In volume, won't
temperature increase?
Nice thing about the bucket still is it's set it and forget it, and it produces a liter ever 24 hours
|
|
|
B(a)P
International Hazard
Posts: 1114
Registered: 29-9-2019
Member Is Offline
Mood: Festive
|
|
| Quote: Originally posted by Yttrium2 | | Quote: Originally posted by B(a)P | I imagine it only comes across at such low concentration as it has effectively zero column length to separate water from alcohol in the vapour phase.
If I were trying to reproduce that set up in the link you provided I would use the element from an old kettle and a thermostat.
If you are going to do it this crudely then use what you already have. Use your biggest cooking pot with a bowl that fits inside. Put the pots lid on
up side down if it is convex and put some ice in the upturned lid then heat it on the stove top. |
I appreciate the feed back.
What kind of thermostat? Do you have a link?
I don't think the stove idea will work, though I've seen it mentioned before. As the alcohol evaporates and the mash reduces In volume, won't
temperature increase?
Nice thing about the bucket still is it's set it and forget it, and it produces a liter ever 24 hours |
Something like this would work https://www.ebay.com.au/itm/220-240V-Temperature-Controller-...
Edit: I have tried a set-up similar to this before. I didn't measure the final ABV, but it was definitely more concentrated than the initial liquid.
https://www.youtube.com/watch?v=ZZyzpDJtK5s
[Edited on 28-4-2020 by B(a)P]
|
|
|
Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
For any distillation - as volume decreases, does temperature increase?
|
|
|
Sulaiman
International Hazard
Posts: 3558
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
Yes, assuming that there is more than one component boiling
not because the volume is decreased hence less stuff to heat
but because the lower b.p. fraction(s) have evaporated leaving the higher b.p. fraction(s)
e.g.1 if distilling water then increasing the heating power results in faster boiling off of water, not increased boiling temperature.
e.g.2 if distilling a mixture of ethanol and water,
increasing the heating power increases the rate of boiling
and as ethanol boils off before water
(ethanol has a higher partial pressure than water at the same temperature)
the concentration of ethanol in the mixture will decrease,
producing a higher b.p. mixture.
i.e. heating power determines vapourisation rate
composition (and pressure) determine boiling point temperature
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
I thought thats how it goes. I think I see what you are saying in (1) - that increasing the temperature of water does not increase its boiling
temperature, -- no matter how hot you get it it still boils at 212F
but lets imagine a flask that is half full, -- half of it boils leaving a quarter = I guess then that that does not increase its vaporization rate?
In the past I guess I got kinda confused thinking no matter how hot I could heat a beaker, it wouldn't increase its vaporization rate -- what a mess
thanks for the response
[Edited on 4/29/2020 by Yttrium2]
|
|
|
Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
What about heating power leads to an increase in the rate of vaporization if the boiling point remains constant?
|
|
|
Texium
Administrator
Posts: 4508
Registered: 11-1-2014
Location: Salt Lake City
Member Is Offline
Mood: PhD candidate!
|
|
Think about it this way: the temperature of a molecule is a function of its kinetic energy. Adding heat to a molecule increases its kinetic energy,
and thus the temperature rises. More heating power = a greater “volume” of heat added. Thus, molecules will gain enough heat to reach the boiling
point faster than they would with less heating power.
|
|
|
Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
ok, I think I understand the above, - thanx Texium
my only remaining question is this --
as volume decreases, does vaporization rate increase?
learned/kinda knew that as volume decreases the temperature does not increase
thinking of heat in terms of volume vs temperature is kinda helpful, I think.
|
|
|
Texium
Administrator
Posts: 4508
Registered: 11-1-2014
Location: Salt Lake City
Member Is Offline
Mood: PhD candidate!
|
|
If we’re considering boiling a pure compound, such as water, for simplicity, then yes typically the rate of boiling will increase as volume gets
smaller. If your hot plate is set to a certain power level and you leave it there the entire time, it will be inputting the same amount of heat to the
solution the entire time. The difference is that at the beginning, say you have a liter of water, the heat is distributed throughout that liter, but
once you get down to 100 mL, you have the same amount of heat going into a tenth of the volume. The rate of boiling will increase.
It’s different if you have components with different boiling points present.
|
|
|
Fulmen
International Hazard
Posts: 1693
Registered: 24-9-2005
Member Is Offline
Mood: Bored
|
|
Wrong. Once the liquid is boiling, all energy absorbed will go into boiling, so in theory the boiling rate should be constant. But depending
on the vessel the heat losses might not be completely constant.
We're not banging rocks together here. We know how to put a man back together.
|
|
|
Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
| Quote: Originally posted by Fulmen | | Wrong. Once the liquid is boiling, all energy absorbed will go into boiling, so in theory the boiling rate should be constant. But depending
on the vessel the heat losses might not be completely constant. |
Can you explain "depending on the vessel the heat losses might not be completely constant"
I was able to answer some of my own questions a simmer is 185-200 degrees, whereas a boil is 212.
[Edited on 4/30/2020 by Yttrium2]
|
|
|
Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
1 last question,
why does blowtorching a spoon of water more quickly reduce the water level than putting the spoon on a 212 degree oil bath?
the water temperature is the same, 212 degree boil -- is it that the spoon gets hotter than 212 because of a pocket of steam?
|
|
|
Texium
Administrator
Posts: 4508
Registered: 11-1-2014
Location: Salt Lake City
Member Is Offline
Mood: PhD candidate!
|
|
| Quote: Originally posted by Fulmen | | Wrong. Once the liquid is boiling, all energy absorbed will go into boiling, so in theory the boiling rate should be constant. But depending
on the vessel the heat losses might not be completely constant. |
Yeah it’s that last part that is the
important caveat of your statement. In reality, heat loss is never constant. I suppose I should have specified, but I was describing what would be
observed in real life, not in theory.
|
|
|
Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
What about my questions?
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
