Melted Airlock

wowbagger · Oct 4, 2012

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 · Oct 4, 2012

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 · Oct 6, 2012

Indeed, do not drink the mead. Somehow, the plastic has degraded and some of it might have leaked into the mead.

Mars Colonist · Oct 6, 2012

Acidity? Any idea of the pH?

akueck · Oct 6, 2012

A lot of plastics will dissolve in organics (petrochemicals, oils, etc). Any contact with that sort of thing?

wowbagger · Oct 7, 2012

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 · Oct 8, 2012

Hmm, how does the stopper look? You said it was soft only where it was in contact with the stopper?

Leeham991 · Oct 9, 2012

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 · Oct 9, 2012

"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_Polymer )

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 · Oct 9, 2012

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 · Oct 9, 2012

The stopper appears fine (it's the plastic screw-on kind).

wowbagger · Dec 19, 2012

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 · Dec 19, 2012

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.

Chevette Girl · Dec 19, 2012

akueck said:
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.

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 · Dec 20, 2012

Chevette Girl said:
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 · Aug 28, 2013

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 · Aug 28, 2013

Really weird... I'd probably be penning a note to the manufacturer, or at least the supplier!

mannye · Aug 28, 2013

I have old (20ish years) airlocks that discolored (brown) but never melted!

capoeirista13 · Aug 30, 2013

SilentJimbo said:
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.

wowbagger said:
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 · Aug 30, 2013

capoeirista13 said:
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.

Melted Airlock

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