Ethanol

[Chris B]

Was very common on many engines in the 70s (particularly small engines such as lawn-mowers) it is still sold as fuel pipe.

[Fredxx]

Except petrol in those days had very little benzene.

I'm intrigued at the plastic and the plasticiser in that pipe. Most plasticisers are soluble in benzene for instance and you end up with a hardened, non-flexible hose.

[The Natural Philosopher]

butyl rubber IIRC

It just ages anyway

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[The Natural Philosopher]

I remember now. Neoprene

[Tim+]

Not transparent.

Tim

[Tim+]

Still not transparent. See eBay link.

Tim

[The Natural Philosopher]

neoprene is transparent

It can be dyed and pigmented of course

[Dave Plowman (News]

Oh, indeed. Lots of plastics come in contact with petrol. Even carbs changed from brass floats to plastic mouldings. But unlikely to be perspex. That is a pretty old plastic as things go.

However, plenty plastics go hard and fracture without being near alcohol. Just with ageing.

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[newshound]

I've never come across transparent neoprene. Norprene is a Saint Gobain trade name, it is not neoprene but its formulation seems to be a trade secret.

The usual black colour of most neoprene will come from a carbon black filler. If I had to guess, I'd expect raw neoprene to be a translucent pale brown, like natural rubber.

The transparent fuel tube is usually PVC. As others have said, loss of plasticisers leads to hardening. Nylon and silicone are sometimes used for fuel, they are naturally colourless, but are both translucent rather than transparent.

[newshound]

On 10/03/2021 22:48, Rod Speed wrote:

Real ale is "alive", it still contains live yeast although most of that is in a layer at the bottom of the barrel in a pub because finings are added just before it is shipped from the brewery. This makes the yeast settle over a few hours after delivery so that the served beer is clear. But the yeast is still working slowly, so carbon dioxide is continuously generated. This serves as a "cover gas" to keep air (oxygen) away from the beer. As you will be familiar down under, "keg" beer which has been pasteurised to kill any remaining yeast is kept with carbon dioxide supplied from a regulated cylinder into the barrel. This usually provides the propulsive force to deliver it at the tap. British beer was traditionally stored in cellars below ground level, although for practical reasons these days most establishments store it at floor level. (A very few keep it at bar level and use gravity feed). The traditional beer pump is a simple lift pump. While this draws air into the barrel as the beer is removed, that passes through a slightly porous "spile" which serves as a coarse filter, and relies on the density of CO2 to keep oxygen away from the beer surface. But, as the barrel empties more and more air gets drawn in; also the older beer produces less CO2 so the protection is imperfect. Acid-forming bacteria can also make their way back from the pump. Good pubs flush or clean the pipes daily, and disinfect them frequently to avoid this.

In the very old days, beer lines were made from lead. Publicans would always draw off the beer that had been in the lines overnight before serving any, but the mean ones would sometimes drink it themselves. This was a regular source of acute lead poisoning in publicans.

In pubs that keep several different "real ales" some barrels are used more slowly than others. It's also possible that small amounts of "bad" bacteria get into the beer at the barrelling stage either air-bourne, during the filling, or because the barrels are imperfectly sterilised (usually by steam cleaning).

Well you did ask.

I might detect signs of beer "turning" a few times a year (this does not make it undrinkable). I only reject a pint once every few years (but I am fussy about my pubs).

[newshound]

Yes. The keg has a single hole in the end face that is positioned at the top. The pressure fitting that clamps into that has a dip tube to the bottom, and a gas feed to the top.

Barrels are used on their side, tilted slightly downhill. The tap fits in the bottom of the lower end face, then the filling and air admittance hole is in the middle of the "cylindrical" part, diametrically opposite the tap. This is sealed with a bung about 50mm diameter, then when serving the bung has a tapered hole about 15mm diameter in it into which a spile is hammered. If drinking at home by gravity, you loosen the spile to serve then knock it back in. In a pub, you use the porous spile once the barrel is tapped. (This may be replaced overnight by the solid one).

I used to brew my own, cheaper but more time consuming. Also, less healthy as you have to check it every day to make sure it's not going off.

[Fredxx]

If you look up "ethanol" in that link, it does.

[Fredxx]

Then you're blind: Ethanol F N

[Fredxx]

Oh good, you finally twigged :-)

BTW: N - Not recommended for continuous use. Immediate damage may occur such as severe crazing, cracking, or permeation losses.

[newshound]

There should have been a smiley at the end of my comment. You may have more self-control than I have :-)

Actually with pubs closed, like you I typically drink one bottle of beer most evenings.

Some years ago my wife went to Oz with a friend who had family there. They went to their local pub one evening, IIRC it was a 120 mile round trip. Their supermarket was nearer, but still a significant distance, which does shift the calculations somewhat.

[Fredxx]

LOL I am aware. Trust you to check under the old name.

[Fredxx]

I did realise that with your post but couldn't be arsed to find another.

However, google shows there are so many people claiming that ethanol crazes acrylic I didn't feel the need to find a better link.

I respect, of course, your experience is different to everyone else's.

[Fredxx]

I thought you were better than this, and someone who said they were a chemist. You should never clean acrylic wit alcohol. You've obviously lost all of your knowledge, assuming you had some:

In some cases Ethanol is used intentionally to create microcracks.

You can deny as much as you like, in the same way the sun rises every morning, alcohol attacks and crazes acrylic. Your personal example of one is unique and you are mistaken.

I am disappointed in you, you actually know less than I thought.