Bladder press

So, you wash your grapes? My point was dirt, bacteria, wild yeasts, even the odd insect find their way into your fermenter anyway if you are working with grapes. The only thing I try to avoid throwing in are mould spores.

Brian

Yes, I wash my grapes before crushing them. And I press indoors to avoid unnecessary exposure to insects and bacteria. And, since I press long and slow, I cover the pressing apparatus with plastic during the procedure, running (sterilized) tubing from the press to the receiving carboy. It amazes me that you are so concerned with microbes in another thread, and unconcerned with tangible contaminants in this one.

sorry, I guess I focused more on the words "bladder" press and ran with that and filling it with too much wine passed through the liver first than I did on the idea of the exploding...

it's been an interesting topic, really... I just made a pneumatic cannon, and am aware of some of the fears and dangers of pvc pipe turning into shrapnel....so I rarely pump it up more than 20-25 psi...although most of the fittings are rated at more than 100 psi.... So it's been interesting seeing how the same topic has been adapted to winemaking! People are pretty clever and really do some neat things to adapt their hobby to what's available to them!

Rick

Why? The pressure in a CO2 cylinder isn't all that high. If you hadn't noticed, the cylinders are made of aluminum rather than steel like the high pressure tanks.

Most of the contents is in the liquid state anyway, so there isn't much potential energy in the event of a rupture. I sure would get cold in a hurry though, and you'd better have a window rolled down!

Tom S

They make scuba tanks from steel and aluminum. Both hold 2200 psi.

-Danno

Yep, that is why they are not allowed on aircraft AND they are required to have a visual AND Hydrostatic inspection periodically. It has been awhile, but I believe the visual is every year and the hydro every 5 years. Hopefully, in the event of abnormal pressure, the tank valve will go before the tank.

Then you are unnecessarily diluting your wine with residual water hanging from the grape clusters. Do you think wineries wash their grapes?

As for my concern with microbes, a careful re-reading of what I wrote will show that I agreed that a thorough cleansing is generally sufficient for winemaking given adequate SO2 levels. It is on the brewing side that I pay particular attention to effectively sanitizing all equipment, since beer does not contain free SO2.

Brian

Which is where my fear lies. I have little fear of a CO2 tank exploding, but I do fear the valve breaking off and turning that cylinder into a very destructive rocket.

Brian

Necessity is a matter of opinion. I don't want insects and bird droppings (not to mention more unpleasant things) in my wine, whether or not I can taste them, and whether or not they will cause infection. I don't believe the "je ne sais qua" improves the flavour of wine, especially when "je sais très bien ce qua".

How much "unnecessary" dilution do you think occurs (not having the least idea of the methods I use for washing -- and perhaps drying -- the fruit)?

I KNOW that some wineries do [wash there fruit], and others don't.

A careful re-reading of what -I- wrote will show that we are essentially in agreement on this point. I advocate the use of hot water, soap, detergent, caustics, and acids when I deem their use appropriate. I do not advocate the "unnecessary" (conceding that the definition of "necessary" is based on opinion) of "sterilizers" and "sanitizers" when a lesser method is sufficient (again conceding the word is subject to opinion). And I do -not- advocate "no-rinse" products without rinsing, because of measurable residuals -- whether or not these levels are deemed "safe" according to the science or politics of the day. [And I prefer to press indoors, where there are fewer insects and bacteria.]

What are the probabilities of this happening? I can't recall reading of an errant CO2 (or other gas tank) shooting through the skies, and assume that it is an extremely rare incidence, far less frequent than burst hoses. If it were not, I suspect that Benevolent Big Brother would have outlawed or severely-restricted their use by now.

The pressurized tanks used for oxy-acetylene welding are fairly heavy, as are propane tanks. I doubt they would move far with a broken valve. If it broke off, the valve itself might turn into a missile, which is why there is a heavy duty metal guard to prevent the valve from being bumped into. I suspect CO2 tanks are similarly constructed.

I do note that such tanks cannot be (legally) transported without a "hazardous materials" license, and the various prerequisite equipment inspections.

Manufacturers of bladder presses specify that water OR compressed air may be used. They caution that a pressure regulator must be used with compressed air (and theoretically with water, if your local supply was more than 30 psi, which it is in some locals). In today's litigious society, if there was a tangible (or even remote) danger of the tank (or valve) exploding, I suspect the instructions for the press would come with the following disclaimer: "WARNING! DO NOT USE COMPRESSED AIR TO POWER THIS APPARATUS!..." followed by a lengthy dissertation of the possible results of such action.

The fact that there is no such warning, indicates to me that there is no substantial probability with that which concerns you.

I know this is way off topic , but YES a high pressure gas bottle will project itself about 3 to 400 YARDS . The way that we emptied old military bottles was to set them up on a ramp , then knock off the valves with a sledge hammer . Made for quick work , got them empty , and more importantly , was a hell of a lot of fun. Greg

importantly

I stand corrected. What size bottles were those, and what was the internal pressure?

Regardless, the air tanks normally used with an air-compressor are designed differently than high pressure gas tanks (the valve is mounted in the center of the horizontal surface, rather than at the end), and the "missle-like" characteristics are considerably reduced.

Moreover, it is unlikely that a person using compressed air to drive a bladder press would have the tank sitting on a ramp, with the valve stem oriented downward. The inertia of the floor (whether wood frame or concrete) would create a resistance, and it would be the valve that would go sailing, not the tank --- if the valve somehow broke.

I also hope that the home winemaker wouldn't be striking the valve with a sledge hammer, and wonder if this could even be accomplished since such tanks (are now required by law to) have a heavy metal guard plate surrounding the valve.

Remember, compressed air (with storage tanks) is routinely used for painting, in workshops, and in automotive garages, all over the world. If the danger described was a realistic concern, we should be equally worried about the safety of craftsmen and passersby. With a 300-400 yard range, no one on the planet would be safe.

I read of a case once where a compressed gas delivery was being made from a truck with a lift gate. Upon lowering the lift, a tank fell over & hit its valve on the truck. It took off like a rocket, across the loading bay, through the entire warehouse and struck some heavy equipment at the far wall. At that point it was deflected upwards, 'til it hit the roof trusses, and, spent at last, fell to the floor. Nobody hurt, but a lot of rubbery knees.

I imagine the valve went toward the truck, but more importantly, all of the contents spewing out under pressure represented reaction mass, which likewise headed truckward, while the tank headed warehouse-ward, under the influence of Newton's Third Law, AKA Action & Reaction. Again, not the result that one would first expect.

And that is exactly what makes this sort of thing so dangerous.... that people routinely underestimate the danger and fail to take adequate precautions. Ask an industrial insurance underwriter, or an industrial safety officer. The replies will be chilling.

BTW, my brand spanking new, 40 liter bladder press (from Italy, by way of Texas) came with all sorts of warnings NOT to use air. It even has a multilingual warning to purge all air from the bladder upon first filling. This last warning is cast into the iron of the cover plate, so I guess they think it's important.

Really, we're not pulling your leg on this. ;)

Luck, Mike MTM

I've never heard of a winery washing its fruit. Care to name names?

Tom S

I've heard of it happening, but not with a CO2 cylinder. The static pressure isn't high enough. (At 70°F a CO2 cylinder is at 825 psi) A fully charged Oxygen, Argon or Nitrogen cylinder could take off like a rocket though.

Propane tanks present more of a fire/explosion hazard in the event of a valve assembly rupture.

An Oxygen [e.g.] tank is a different matter. If the neck snaps off, the force that tank will move with is proportional to the area of the orifice multiplied by the gas pressure. Even if the area is only ¼ of a square inch, a tank at 2200 psi would have 550 pounds of force pushing it around. I wouldn't want to be in the way of that!

If it

I assume you're referring to the metal cap on a high pressure cylinder. You have to remove that cap to put the cylinder into service. It's there only to protect the valve assembly from damage, so you don't have a hundred pound tank go shooting off like a missile when the valve snaps off in an accident.

They aren't.

APPARATUS!..."

False. Most of the bladder presses are made in Italy. Do you _really_ think you could successfully sue the Italians for product liability in the event of an accident? Good luck! :^/

Tom S

I always thought that the reason that liquids were used was the compresssed much less then air. I.E. you lose more volume as you compress air then you lose by compressing liquids.

but it is an interesting idea on the conversion, but i still see the problem stated above able to play out here, the amount of pressure to operate the press must be a lot higher then water.

"Ray" wrote in news:sHPub.1466$ snipped-for-privacy@newssvr22.news.prodigy.com:

like most people here have said, there is some hazard, but look at what the valves went through to get them to that point. A little care with this equipment is required, but they are not however ultra sensative. I have hauled a blow torch around in my trucks before. Me and the trucks both survived, and its important to note because i'm a farmer, so the truck and the tank were not always on the nice roads that you see all the time.

But like i said, some caution is good, but leave paranoia at the door, it will cause you lots of problems. The tanks can take some abuse, but its still best to minimize it.

good luck and happy winemaking

Quakeholio

"Brian Lundeen" wrote in news:bpj65b$1ov7te$ snipped-for-privacy@ID-202290.news.uni-berlin.de:

The grapes outside the bladder don't know whether there is 45 psi water or

The difference is in the amount of _volume_ required between the two to achieve the same pressure. According to Boyle's Law, it would take about four times the volume of air to reach 45 psi as it would with water, because the air is compressing as the pressure builds.

Tom S

I dunno. I have a couple of italian idropresses,and so far as I know, they're designed to use compressed air. I run them to 4 bar (64 psi) on a regular basis, so far without problem.

That said, I lie on the ground when adding pressure, so that if it blows, it blows OVER my head, rather than through it. :-)

Dave