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wowbagger
10-04-2012, 03:18 PM
So, last weekend I racked a 2-ish month old spiced mead. When I took out the airlock (standard cup-in-cup type) I noticed that the tip (where the stem sticks into the carboy stopper) was all soft and squishy. It looks almost like it melted, and days later it's still soft. My first theory was that this was from residual StarSan (since I put some in the airlock) but I've never seen this happen before so naturally I'm puzzled.

Thoughts?

wayneb
10-04-2012, 05:36 PM
Don't drink the mead.


Seriously, I'd take some of the mead out and allow it to set in a plastic drinking cup to see if it has any effect on the cup.


I have heard of folks having trouble storing StarSan at high concentrations in some plastics, but I have never seen any degradation in any of the plastics that are customarily used in home brewing equipment. I've had stuff soaking in StarSan for months with no ill effects, other than to fog up some clear plastics.

Fortytwo
10-06-2012, 07:58 AM
Indeed, do not drink the mead. Somehow, the plastic has degraded and some of it might have leaked into the mead.

Mars Colonist
10-06-2012, 09:40 AM
Acidity? Any idea of the pH?

akueck
10-06-2012, 11:34 AM
A lot of plastics will dissolve in organics (petrochemicals, oils, etc). Any contact with that sort of thing?

wowbagger
10-07-2012, 08:59 PM
Petrochemicals? Not that I can think of! Honey, water, allspice, cinnemon, clove... then the aforementioned Star San are the only things that should have come into contact with it.

If I put a sample into a plastic container and nothing happens it should be ok right?

akueck
10-08-2012, 08:34 AM
Hmm, how does the stopper look? You said it was soft only where it was in contact with the stopper?

Leeham991
10-09-2012, 12:41 AM
Where exactly did you get the airlock from?

I heard somewhere that standard plastic bottles will go soft if you put wine in them because the plastic doesn't like the alcohol, and maybe a the alcohol fumes???

I have a spiced mead going on a month and I have half a mind to disregard the "don't touch it until the raisins sink" part of the recipe and pull out my airlock to take a look. I got mine for about 20 pence so it's as cheap as they come...

snuesen
10-09-2012, 04:00 AM
"the degradation of plastic can be said to begin as soon as the polymer is synthesised, and is increased by residual stresses left by moulding processes. This can be followed by exposure to light (especially UV), humidity, oxygen, heat, bacteria and stress. Plastics can also be contaminated by other materials, including other plastics." ( www.azom.com/article.aspx?ArticleID=1655#_Recognition_of_Polyme r )

Maybe just unlucky with the airlock, although such a fast degradation is very suspect. I'd also play it safe, constituents of any "plastic" are not safe to ingest, of course.

Chevette Girl
10-09-2012, 10:54 AM
Yeah, just because your mead didn't dissolve the airlock doesn't mean it's not contaminated with dissolved airlock or whatever did dissolve it... I wouldn't risk trying the mead either, unless you have a friend in a lab somewhere willing to test it for... well, it could be anything...

wowbagger
10-09-2012, 11:36 AM
The stopper appears fine (it's the plastic screw-on kind).

wowbagger
12-19-2012, 09:30 PM
Sorry to Zombify this thread, but I think I solved the mystery.

A coworker of mine came to me the other day to show me an odd discovery he'd made. He was using one of those black plastic cafeteria knives to cut into a orange. The juice and the rind were enough to react with the knife and cause it to melt.

I had orange rind in my recipe, which definitely came into contact with the airlock. I suspect this is what happened.

Completely random story: The other day I was speaking with another coworker who mentioned knowing of a good local supply of honey. I said "Oh that's great, I make mead." The coworker looked at me and said, "Oh, that's interesting. Do you make beer out of it too?"

I had absolutely no response to that...

akueck
12-19-2012, 10:09 PM
Hmm. Organic acids? Certainly they are corrosive to lots of things, although food-use plastics would supposedly be made with that in mind. On the other hand, perhaps not. :rolleyes:

Chevette Girl
12-19-2012, 11:13 PM
Hmm. Organic acids? Certainly they are corrosive to lots of things, although food-use plastics would supposedly be made with that in mind. On the other hand, perhaps not. :rolleyes:

I could see the oils in the orange peel doing it but you'd think it should be able to resist some acid. Wonder if they've done something to make them more biodegradable that now causes 'em to biodegrade while you're still using them...

skunkboy
12-20-2012, 09:27 PM
I could see the oils in the orange peel doing it but you'd think it should be able to resist some acid. Wonder if they've done something to make them more biodegradable that now causes 'em to biodegrade while you're still using them...

Or just made from much cheaper software plastic, they don't seem to as nice as the ones that I bought 5 or 6 years ago now.

SilentJimbo
08-28-2013, 03:58 PM
I've just had an airlock "melt". Just so happens that this is the first mead I've made using orange zest, so looks that is indeed the cause. The zest never came into direct contact with the airlock, but maybe it's from the oils when evaporating off? I'm going to do a test with the ruined airlock to confirm.

Chevette Girl
08-28-2013, 07:18 PM
Really weird... I'd probably be penning a note to the manufacturer, or at least the supplier!

mannye
08-28-2013, 10:57 PM
I have old (20ish years) airlocks that discolored (brown) but never melted!

capoeirista13
08-30-2013, 09:55 AM
I've just had an airlock "melt". Just so happens that this is the first mead I've made using orange zest, so looks that is indeed the cause. The zest never came into direct contact with the airlock, but maybe it's from the oils when evaporating off? I'm going to do a test with the ruined airlock to confirm.


Sorry to Zombify this thread, but I think I solved the mystery.

A coworker of mine came to me the other day to show me an odd discovery he'd made. He was using one of those black plastic cafeteria knives to cut into a orange. The juice and the rind were enough to react with the knife and cause it to melt.

I had orange rind in my recipe, which definitely came into contact with the airlock. I suspect this is what happened.

Completely random story: The other day I was speaking with another coworker who mentioned knowing of a good local supply of honey. I said "Oh that's great, I make mead." The coworker looked at me and said, "Oh, that's interesting. Do you make beer out of it too?"

I had absolutely no response to that...


I frequently use orange and orange zest in many of my recipes. Every time I've made a batch with even just a few oranges the bottom of my airlock melts.

mannye
08-30-2013, 10:31 AM
I frequently use orange and orange zest in many of my recipes. Every time I've made a batch with even just a few oranges the bottom of my airlock melts.

I like it when a mystery is solved. Guess those glass airlocks have a use besides being pretty after all.

wowbagger
08-31-2013, 11:18 AM
Way back when I started this thread, I did some poking around on the internet. Apparently it's not the acidity of the zest, it's the 'essential oil' in the rind (which has a very fancy technical name). The oil works as a solvent on many petrochemicals, which includes some plastics and Styrofoam.

I also learned that, apparently, this oil is used to 'stress test' the resilliance of denture bonding materials.

SilentJimbo
08-31-2013, 02:35 PM
Yeah, it's the oils. I asked my father about it and received a lengthy, convincing explanation involving oils and solvents and poly-things...