Report on leeching of plastics into ethanol

[The Chemist]

Interesting. With just a quick look-through, I tend to agree with schnell. I do note that on page 157 they account for the 'column crap' (yes...that's a scientific term... ).

As to any usefulness, I'll have to have a more thorough read. But, I'll have to do that for work, anyway, now that it's come to my attention. May take several days.

[Husker]

As to any usefulness, I'll have to have a more thorough read. But, I'll have to do that for work, anyway, now that it's come to my attention. May take several days.

Since most of what you end up doing, falls under NDA, is there a possible way you could post any tidbits you find to HD, PRIOR to releasing it to whomever you are obtaining the data for?

Pretty please

H.

[The Chemist]

You mean any useful tidbits I find in the present study in question? That's no problem. I can discuss public domain stuff.

[simonmw3]

Thanks to the original poster. This was very useful for me as I have been thinking of using a short length of silicone pipe between the top of the reflux column and the condenser. The reason I wanted to do this is because copper is a very good conductor of heat. A lot of still designs have cold water on copper pretty close to the top of the reflux column that we are trying to keep around 78C. This means that a lot of heat must be wasted by flowing through the copper directly into the condenser. In other words, the heat source is typically trying to boil off the alcohol but the copper is conducting the heat away to the cooling water.

My idea was to put a short length (say 10cm/4") of silicone tube just after the head of the reflux column and immediately before the condenser. Silicone conducts heat much less that copper so the alcohol vapour should be able to go from the hot top of the reflux column straight into the cool condenser via a short length of silicone without much heat being conducted through the tube. Therefore, the still should be more energy efficient. (Does that explanation make sense?)

I had been worried about the effect of the silicone tube reacting with the alcohol. However, it seems the leeching effects are relatively small and my idea only requires a small length of tube with a small surface area that the alcohol vapour would only be in contact with for a short time. (Note: when I originally considered the concept, I thought about using PVC until I read about the plasticisers in it.) Generally, I would also be against a "plastic still". However, this is just a small silicone part to try and improve the energy efficiency so that it hopefully distils faster or with less power.

What does anybody else think of this idea?

[Tater]

Thanks to the original poster. This was very useful for me as I have been thinking of using a short length of silicone pipe between the top of the reflux column and the condenser. The reason I wanted to do this is because copper is a very good conductor of heat. A lot of still designs have cold water on copper pretty close to the top of the reflux column that we are trying to keep around 78C. This means that a lot of heat must be wasted by flowing through the copper directly into the condenser. In other words, the heat source is typically trying to boil off the alcohol but the copper is conducting the heat away to the cooling water.

My idea was to put a short length (say 10cm/4") of silicone tube just after the head of the reflux column and immediately before the condenser. Silicone conducts heat much less that copper so the alcohol vapour should be able to go from the hot top of the reflux column straight into the cool condenser via a short length of silicone without much heat being conducted through the tube. Therefore, the still should be more energy efficient. (Does that explanation make sense?)

I had been worried about the effect of the silicone tube reacting with the alcohol. However, it seems the leeching effects are relatively small and my idea only requires a small length of tube with a small surface area that the alcohol vapour would only be in contact with for a short time. (Note: when I originally considered the concept, I thought about using PVC until I read about the plasticisers in it.) Generally, I would also be against a "plastic still". However, this is just a small silicone part to try and improve the energy efficiency so that it hopefully distils faster or with less power.

What does anybody else think of this idea?

I wouldn't do it or drink your product .

[schnell]

What does anybody else think of this idea?

lame idea, with a lame attempt at justification.

[seravitae]

No idea is lame... Some ideas put into practice is a bad idea though.

The amount of energy saved by using that short amount of silicone tubing is infintely smaller than the amount of energy used elsewhere in your process - you'd save more money insulating still and copper work and come out with a better product at the end.

Also reflux distillation is inherantly much more power hungry than standard distillation, due to the fact that you're consantly recondensing your product and removing energy you just supplied into the system. there are other ways to save power in this case (solar/waste heat pre-heating), vacuum distillation.. but certainly it seems most appropriate to use copper or SS only in the vapour path.

[alice]

I'm a little confused. In "The rules by which we live" it states "posts about any form of plastic use will be edited, deleted or locked" but this thread is allowed to continue unabated. How come?

[Tater]

I'm a little confused. In "The rules by which we live" it states "posts about any form of plastic use will be edited, deleted or locked" but this thread is allowed to continue unabated. How come?

Times change info gets better . We have been working on this just haven't finished with changes . The no plastics rule was first written cause all we were getting was its ok to use cause i use it and aint dead yet.We always asked for info to back up whatever plastic was being discussed but wasn't provided any.Most posts ended up in flame wars.Hence the rule 8.We will have a materials section added to forum soon .Any material with proper researched info will be gladly admitted. tks for asking staff

[seravitae]

I think that's a slight pipedream in the sense that we're a big bunch of molecules, and so is every material on this planet, and will have an effect on us in some way. I think about the safest setup you could make would either be pure glass, or pure stainless steel (direct mating, no gasketed clamps). Even the suggested cork gaskets will leach stuff. A lot of people on this board are quick to discount plastics on the account of leeching, suggesting natural cork as a safe gasket, however a 10 second search yeilds:

Analysis for chloroanisoles and chlorophenols in cork by stir bar sorptive extraction and gas chromatography–mass spectrometry, R.M. Callejon, A.M. Troncoso, M.L. Morales ∗

..Which shows various chlorinated aromatic products able to be extracted by ethanol, the chlorinated aromatic products suggestibly being formed by pesticides used on the cork wood (even if its *natural cork*, not processed, it is stil likely treated with something) and biological conversion.

The bottom line is you can be ultra paranoid about everything, every material, even those sworn by members on this forum, yet everything is likely to leave some trace element with biological activity in your booze. Also half of the 'flavour' elements in a brew probably have biological activity, and not all that good for you based on what i've seen.

[schnell]

The rule of thumb was a good one. Some things are tried and true, and these practices should still be encouraged.

[stillvodka]

The rule of thumb was a good one. Some things are tried and true, and these practices should still be encouraged.

Your spot on there Schnell.