Questionable residue in Ziplock Gallon-Size Freezer Bags???

[soyboy]

I bought my first Weber kettle last April, and am trying to catch up on all the years I wasn't grilling. My question is this: Has anybody else noticed that a milky, gelatinous substance forms when a few ounces of water are added to new Ziploc Freezer Bag and shaken? I have seen this every time I tried it. The manufacturer (S.C. Johnson and Son) has no idea. They sent me some coupons for free bags. Since many of us use marinades, I am thinking this might be something to investigate. Any ideas? Thanks...

[fuzzydaddy]

I use quart, gallon and 2 gallon ziplock freezer bags and have never seen this. Has it done this with water from 2 different sources, such as your local water and bottled water? Hope you get this sorted out.

[ribeyeguy]

Just so I'm clear on what you're saying, you take a new, unused Ziploc gallon sized freezer bag out of the box, add a few ounces of water, shake it up and some kind of goo forms? Two or three ounces isn't much in a gallon sized bag but can you tell if it's like a surface gel or does the entire volume turn into it? SCJ is based in my hometown (Racine, WI) and we do quite a bit of business with them. Give me some more details and I'll ask some of the people that I know there about it.

Also, what fuzzydaddy said, try it with your tap water versus bottled water and see if you get the same results.

[soyboy]

New bag from the carton, add 1/4 cup water, zip shut, and shake for a few seconds. The resulting water looks cloudy, and when you let it sit for a day a distinct cloudy gel forms and floats on the surface. I will try it tomorrow using my Brita water and tap water and report back. My dad just gave me a sous vide unit as an early Christmas present today, so I am motivated to sort this out. I want to do rib-eyes from Costco in the sous vide. Thanks for your reply, ribeyeguy!

[AZRedneck]

I don't want to sound like Captain Obvious here, but SV water should never touch the product because it should be safely enclosed inside a zipper bag or a vacuum bag. I just got my Anova today, and have never done anything with the SV method, so I am no expert, or even experienced user. My thoughts are that your gel in your bags are absolutely not what discerning diners would call normal, but that shouldn't affect the SV process.

[soyboy]

Thanks for your reply redneck...For the time being I will be rinsing my Ziploc bags before using them for SV. Have fun with yours!

[Mr. Bones]

An additional thought, if I may...

Are you using straight tap water? I have lived many places where the water would do that, sans ziploc.

Fwiw, all water that I consume internally goes though a filter pitcher.

Best of luck in isolating / eradicating the problem.

[soyboy]

It happens with any type of water. I'm with you Mr. Bones...always filter my water first!

[jerrybell]

I'm late in responding here but: At work we sometimes send samples of small metallic parts to an outside testing lab to identify surface chemistry on the parts. We do not package the samples in zip closure bags because many brands use a "release agent" on the interior of the bags that can transfer to the samples and influence the test results. I assume you are seeing the result of this minute amount of release agent becoming suspended in the water you added to the bag.

[docblonder]

jerrybell is probably correct. There are two likely sources of contamination. First, the molding equipment is coated with a greasy substance so the hot plastic film doesn't stick as the bag is formed. Sometimes, when the line is starting up, too much release agent is present.

The second reason might be the plastic, which is melted from small beads, did not fully convert or cure during the heat stage. Some uncured "monomers" might be floating in your water. Some beads contain additives called "plasticizers" which keep the film flexible. They too can leak into the water, or contaminate samples.

While ziplock bags are probably pretty safe compared to, say, breathing in wood smoke for an afternoon, you might consider springing for actual sous vide bags from a reputable manufacturer. They pay strict attention to these issues, and their plastic can tolerate higher temps than a ziplock.