PVC pipe kegs

[BetterSense]

Personally, I think 2.5 or 3 gallons is the perfect size for a keg, because I can bottle half a batch and keg the rest. I manage to drink the keg before it gets old...my consumption is not high and I like a lot of varieties on hand.

Unfortunately kegs are expensive and the 3-gallon ones take up just as much floor space as the 5-gallon ones. The ideal 3-gallon keg would be like 5 inches in diameter and as tall as a chest freezer.

4-inch PVC is cheap and has a 133 PSI working pressure. It would be easy to glue on caps and install fittings on a stub-out drilled into the end. I used to make high pressure water cannons and potato guns out of 4-inch PVC all the time.

The problem is, I don't think PVC is a good material for a keg, for some technical chemistry reason. Right?

 

[LakeWobegon]

I think a 5" ID pipe would have to be ~3 feet tall to hold 3 gallons. Then you'd need to cap off one end and somehow create the fittings. A used corny keg only costs $35 so its not worth the time.

 

[Mojzis]

Personally, I think 2.5 or 3 gallons is the perfect size for a keg, because I can bottle half a batch and keg the rest. I manage to drink the keg before it gets old...my consumption is not high and I like a lot of varieties on hand.

Unfortunately kegs are expensive and the 3-gallon ones take up just as much floor space as the 5-gallon ones. The ideal 3-gallon keg would be like 5 inches in diameter and as tall as a chest freezer.

4-inch PVC is cheap and has a 133 PSI working pressure. It would be easy to glue on caps and install fittings on a stub-out drilled into the end. I used to make high pressure water cannons and potato guns out of 4-inch PVC all the time.

The problem is, I don't think PVC is a good material for a keg, for some technical chemistry reason. Right?

Three chemicals are at the core of manufacturing: First, chlorine gas is used to produce ethylene dichloride (EDC). Second, the EDC is converted into vinyl chloride monomer (VCM). Finally, the VCM is converted into the PVC. VCM and EDC are extremely hazardous, with vinyl chloride causing a rare form of liver cancer that damages the liver and central nervous system.

The EPA classifies vinyl chloride as a known human carcinogen. When PVC is manufactured by workers or burned when discarded, numerous dioxins are formed and released into the air and water. Dioxins are a highly toxic group of chemicals that build up in the food chain and can cause cancer, as well as harm the immune and reproductive systems.

The volatile organic compounds (VOCs) that PVC releases can also cause eye, nose and throat irritation; headaches; loss of coordination; and nausea. Key symptoms associated with exposure include eye irritation, nose and throat discomfort, difficulty breathing, allergic skin reaction, headache, nausea, vomiting, fatigue, dizziness and nosebleeds. Phthalates have been linked to reproductive problems, including shorter pregnancy duration and sperm damage in males.

“The brain is a major target for VOCs, causing everything from headache and loss of concentration to learning disabilities in children whose mothers were exposed before their birth, as shown in a recent Canadian study,” says David O. Carpenter, MD, director of the Institute for Health and Environment at the University at Albany, SUNY. “Since there are safe alternatives to vinyl shower curtains, such exposures should always be avoided.”

from: http://www.organicauthority.com/blog/health/understanding-pvc-dangers/#s.abu35odgabaaa

 

[BetterSense]

OK. But PVC pipe is used for water supply all over the world.

 

[BetterSense]

I think a 5" ID pipe would have to be ~3 feet tall to hold 3 gallons

.
2.8 feet. A 2.5 gallon one would be shorter.

Then you'd need to cap off one end and somehow create the fittings

Not hard. They have PVC fittings.

A used corny keg only costs $35 so its not worth the time.

3 gallon kegs cost $100+, Also, you can only fit about 4 of them in a medium size freezer. Just think how many 5 inch pipes you could fit in one.

 

[lumpher]

Three chemicals are at the core of manufacturing: First, chlorine gas is used to produce ethylene dichloride (EDC). Second, the EDC is converted into vinyl chloride monomer (VCM). Finally, the VCM is converted into the PVC. VCM and EDC are extremely hazardous, with vinyl chloride causing a rare form of liver cancer that damages the liver and central nervous system.

The EPA classifies vinyl chloride as a known human carcinogen. When PVC is manufactured by workers or burned when discarded, numerous dioxins are formed and released into the air and water. Dioxins are a highly toxic group of chemicals that build up in the food chain and can cause cancer, as well as harm the immune and reproductive systems.

The volatile organic compounds (VOCs) that PVC releases can also cause eye, nose and throat irritation; headaches; loss of coordination; and nausea. Key symptoms associated with exposure include eye irritation, nose and throat discomfort, difficulty breathing, allergic skin reaction, headache, nausea, vomiting, fatigue, dizziness and nosebleeds. Phthalates have been linked to reproductive problems, including shorter pregnancy duration and sperm damage in males.

“The brain is a major target for VOCs, causing everything from headache and loss of concentration to learning disabilities in children whose mothers were exposed before their birth, as shown in a recent Canadian study,” says David O. Carpenter, MD, director of the Institute for Health and Environment at the University at Albany, SUNY. “Since there are safe alternatives to vinyl shower curtains, such exposures should always be avoided.”

from: http://www.organicauthority.com/blog/health/understanding-pvc-dangers/#s.abu35odgabaaa

so i take it you're against this idea?

 

[JuanMoore]

OK. But PVC pipe is used for water supply all over the world.

There is no denying that PVC leaches vinyl chloride and organotin compounds into water, both of which are toxic. For most potable water systems the amounts are low enough that most people/municipalities/governments consider it to be a safe material, but there are countries that don't allow it in residential water supply systems.

The main issue with mixing beer and PVC is that beer is much more acidic than tap water. The amounts of toxins leached from the PVC increase by huge margins when the ph of the liquid is lowered significantly. The toxic solvents in the glues used for the joints and fittings will also be more likely to leach into the acidic beer than it would in water. Will the lower ph increase leaching of toxins enough to become harmful or create an off flavor? I have no idea, but it's certainly possible. The thing it has going for it is the low temperature of a kegerator, which would help slow down the leaching of toxins.

I love the idea, but I'm not sure I would personally be comfortable with PVC in contact with my beer for extended periods of time. Polyethylene and HDPE are both pretty safe, but polyethylene pipe is absurdly expensive, and HDPE pipe requires a special machine to connect the fittings since they're actually melted together instead of glued.

 

[BetterSense]

Cat PET be solvent-welded? PET pipe is probably also absurdly expensive, but widely used in my industry...

 

[Mojzis]

OK. But PVC pipe is used for water supply all over the world.

Water lacks sufficient ions.

so i take it you're against this idea?

Obviously.

There is no denying that PVC leaches vinyl chloride and organotin compounds into water, both of which are toxic. For most potable water systems the amounts are low enough that most people/municipalities/governments consider it to be a safe material, but there are countries that don't allow it in residential water supply systems.

The main issue with mixing beer and PVC is that beer is much more acidic than tap water. The amounts of toxins leached from the PVC increase by huge margins when the ph of the liquid is lowered significantly. The toxic solvents in the glues used for the joints and fittings will also be more likely to leach into the acidic beer than it would in water. Will the lower ph increase leaching of toxins enough to become harmful or create an off flavor? I have no idea, but it's certainly possible. The thing it has going for it is the low temperature of a kegerator, which would help slow down the leaching of toxins.

I love the idea, but I'm not sure I would personally be comfortable with PVC in contact with my beer for extended periods of time. Polyethylene and HDPE are both pretty safe, but polyethylene pipe is absurdly expensive, and HDPE pipe requires a special machine to connect the fittings since they're actually melted together instead of glued.

Exactly. Why take the chance? Spend the extra 10$ and avoid carcinogens. I'm all for doing things more economically, but I doubt the risk is worth it.

 

[Revvy]

Adventures in Homebrewing sells 2.5 gallon kegs for 79bucks.

 

[zachattack]

The chemical leaching is a very good point. Also, PVC piping isn't for use with compressed gasses, that pressure rating is for liquid. There was a post a little while ago on this where a few of us strongly recommended against it:

https://www.homebrewtalk.com/f35/co2-manifold-question-349799/

 

[Bobby_M]

It's not the first time this was discussed and I sure don't want to go over it again. https://www.homebrewtalk.com/f35/plastic-pvc-pipe-5-gal-mini-keg-78012/

 

[audger]

OK. But PVC pipe is used for water supply all over the world.

water does not = beer. beer is chemically much different than water; different pH, sugar, alcohol, CO2, hop acids...

i like the idea, just not the materials being chosen. also you would want a pressure release valve if you were to ever try to make something like this. i would imagine you would have sanitation issues eventually with crap builiding up around the joints, scratches inside, or voids around the joints as well.

seems like a lot of headache to avoid paying $35 for a tried and true corney keg without any of those issues...

 

[porcupine73]

And even if PVC is used in potable water plumbing it doesn't mean it's good in that application. Many of these things are slow poisons in these small doses over time. Just because we don't keel over dead from it within a week does not mean it is safe. At one time lead was popular for water supply pipes too. The U.S. insists on adding toxic fluoride to our drinking water whereas many other countries have long since banned it.

 

[SpookyAlmond]

Toxicity is a dose response. Reason U.S. uses flouride is because it is effective in the pipe after water treatment. It's been a while since those classes in college but iirc the risk of using the flouride is quite low in the concentrations we use.