Looks like I’m going to be repeating myself. The alternate vacuum packing post is part of a longer article that I am currently writing. From the questions asked and other comments I realized that more was needed. Here I did try to answer the questions on the fly with little thought. I decided to make the necessary clarifications in my article. The following is the added information in a more coherent form. I decided that even though much is a repeat of some that I already did. It would be easier to post it complete to present a better picture. I also want to thank bountyhunter because I never thought of the possibility of silicon sealent.

A couple of tips about using the ziploc like bags. Forget the thin sandwich bags. They will not hold up go with the heavier duty freezer bags. Frequently these bags will not hold a vacuum very well. A small part of this is plastic is somewhat permeable to O2 and other gases. This can be delayed to an extent by double bagging. Furthermore the error of over filling the bag. Yes we all probably suffer from the desire to get the most out of what we do by over packing. If this is done this can put a strain on the sealing area. As they are meant be reopened this strain can cause at seal to separate. Another factor is it is common not to fully seal the baggies. The interlocking strips are engaged but not completely seated. You may need to press them closed several times to be sure. Finally a trick I picked up from a company that makes a small hand held mechanical vacuum pump. Placing a small drop of oil in the seal juncture. I repeat a small drop. You want just enough to form a very thin film in the seal tracks not flood the bag getting oil on everything. This forms a hydraulic type lock that helps hold the seal better. Vegetable oils are best for this. Petroleum oils can deteriorate the plastic of the bag and if edibles are involved can contaminate the product.

OK, you have sealed the bag is there anyway to improve the seal on these. Yes, several ways. The opening can be taped shut using clear packing tape or duct tapes. For more long term you can place a bead of silicon caulking in the top next to the normal seal. This can be the more permanent type goo or those strips that are more temporary but could possible be reused. Then there are those heat-sealing devices. The ones touted for re-closing chip and cereal bags. I have tried one and am not highly impressed. The seal is very narrow about like a fine pencil line. It is far to easy to leave gaps or burn through both leaving holes in the seal. I suppose that with a lot of practice you could overcome this. I would be happier with a wider sealing area such as those on the vacuum sealing machines. If one of these are used it would be advantageous to perform this heat seal between the zipper closure and the outside because they often cut through the plastic. If done between the storage area and the seal the cut would separate the sealing area defeating the idea of a double seal.

Plus wouldn't dissolved O2 and CO2 in the water be liberated once the ice melted?

Wellspring:

No, it would be Hydrogen and Oxygen (H2O) that would be liberated (VIVA La France!).

Bountyhunter

Well, I suppose water vapor also. What I meant is that water also has dissolved CO2 (carbonic acid) and O2 (what fish breathe). Not sure what, if any, other gases are normally present dissolved in water.

What I'm not sure about is whether they'd be liberated when the air pressure goes down. I suppose so, since that's how your lungs remove CO2 from your bloodstream. But is it enough to make a difference?

Wellspring:

Unless my memory has completely failed me, CO2 is carbon dioxide, a gas.

O2 is merely two molecules of oxygen, a gas.

The definition for water is H2O (2 parts hydrogen with 1 part oxygen.) which does not allow for the presence of other components.

Therefore, evaporation of ice, water in a frozen state, and subsequent evaporation of water would release only hydrogen and oxygen.

Bountyhunter

P.S. Not many people know this, but water is not a conducter, but is an insulator of electricity. Electricity will not flow through water, period.

Yep, you're right. Pure water is not a conducter.
But if any dirt or salt in it.......


IMHO evaporation of water gives ... water ! <img src="/images/graemlins/grin.gif" alt="" /> just a change of state (?), not a chemical reaction.
You would get hydrogen and oxygen if you can break the H2O molecule (i.e. using a DC voltage)

About Wellspring post :
I think he was not speaking about the H2O molecule itself, but about all sort of stuff that can be dissolved in water like salt, strawberry syrup etc... and O2 and CO2 ...
Fishs use O2 "mixed" in water, they don't break H2O molecules with their gills.

So I guess both of you are right, but are not speaking about the same thing ! <img src="/images/graemlins/cool.gif" alt="" />

Yep, that's it exactly!

Frenchy:

I wish you hadn't given it away as I was waiting for a whole spate of people telling me I was full of it up to my eyeballs.

Hell, I know certified electricians who have argued with me that water conducts electricity, with darn few of them knowing it is the suspended impurities in water that conducts the electricity.

I was under the impression that water vapor breaks down into its component parts during the boiling process as I have never seen it reconsitute in the air. I do know that water vapor does condense on cold surfaces, but never did follow up on how that comes to pass.

Bountyhunter