This is something that's been bothering me for a while, but I can't
find much information about it. When (non-enameled) cast iron gets
seasoned, what exactly is happening chemically? What is that layer
you're depositing on the iron? It seems to me that you're essentially
burning oil and food particles onto the iron. Last time I checked,
burned, smoked oil is believed to be carcinogenic. The fumes from the
seasoning process certainly aren't very pleasant, and are presumably
carcinogenic. And yet, health authorities consistently recommend
cooking in cast iron as a way to increase dietary iron intake -- are
they simply overlooking the potential carcinogenic effects, or has it
been studied and found to be safe?

Anybody know of any hard data about this? Unfortunately, "My grandma
has been cooking in cast iron for 97 years and she's still alive and
kicking" doesn't count as hard data, sorry. Yes, people have been
cooking in cast iron for a long time, and the human species as a whole
continues to thrive. But then, lots of people get cancer, and we
don't usually know why.

I'm not trying to be alarmist and tell people not to use cast iron.
I'm just curious and somewhat concerned.

TIA,

Randall

"Randall Nortman" > wrote in message
nk.net...
> This is something that's been bothering me for a while, but I can't
> find much information about it. When (non-enameled) cast iron gets
> seasoned, what exactly is happening chemically? What is that layer
> you're depositing on the iron? It seems to me that you're essentially
> burning oil and food particles onto the iron. Last time I checked,
> burned, smoked oil is believed to be carcinogenic. The fumes from the
> seasoning process certainly aren't very pleasant, and are presumably
> carcinogenic. And yet, health authorities consistently recommend
> cooking in cast iron as a way to increase dietary iron intake -- are
> they simply overlooking the potential carcinogenic effects, or has it
> been studied and found to be safe?
>
> Anybody know of any hard data about this? Unfortunately, "My grandma
> has been cooking in cast iron for 97 years and she's still alive and
> kicking" doesn't count as hard data, sorry. Yes, people have been
> cooking in cast iron for a long time, and the human species as a whole
> continues to thrive. But then, lots of people get cancer, and we
> don't usually know why.
>
> I'm not trying to be alarmist and tell people not to use cast iron.
> I'm just curious and somewhat concerned.
>
> TIA,
>
> Randall

If you do the seasoning properly the oil does not burn. Rather the prolonged
heat and the contact with the metal (and air) causes a change in the
molecular structure of the oil - the molecules oxidize and bond to each
other forming a hard, dense, dry layer. THis layer is the seasoning that
protects the metal of the pan and also provides the stick-resistant
properties.


--
Peter Aitken
Visit my recipe and kitchen myths page at www.pgacon.com/cooking.htm

"Randall Nortman" > wrote in message
nk.net...
> This is something that's been bothering me for a while, but I can't
> find much information about it. When (non-enameled) cast iron gets
> seasoned, what exactly is happening chemically? What is that layer
> you're depositing on the iron? It seems to me that you're essentially
> burning oil and food particles onto the iron. Last time I checked,
> burned, smoked oil is believed to be carcinogenic. The fumes from the
> seasoning process certainly aren't very pleasant, and are presumably
> carcinogenic. And yet, health authorities consistently recommend
> cooking in cast iron as a way to increase dietary iron intake -- are
> they simply overlooking the potential carcinogenic effects, or has it
> been studied and found to be safe?

Burning? Odors? You are doing something wrong if that is happening. Proper
seasoning is when the heated oils polymerize. They change their physical
state and seal the iron.

POLYMERIZATION: a chemical reaction in which two or more molecules combine
to form larger molecules that contain repeating structural units

You are assuming the fumes are carcinogenic, but in reality, there are no
fumes in properly seasong of the iron.



>
> I'm not trying to be alarmist and tell people not to use cast iron.
> I'm just curious and somewhat concerned.

You seem to be very concerned about it though, and have no evidence to base
anything about it. Borderline alarmist, IMO.
--
Ed
http://pages.cthome.net/edhome/

On 2005-12-14, Edwin Pawlowski > wrote:
>
> "Randall Nortman" > wrote in message
> nk.net...
>> This is something that's been bothering me for a while, but I can't
>> find much information about it. When (non-enameled) cast iron gets
>> seasoned, what exactly is happening chemically? What is that layer
>> you're depositing on the iron? It seems to me that you're essentially
>> burning oil and food particles onto the iron. Last time I checked,
>> burned, smoked oil is believed to be carcinogenic. The fumes from the
>> seasoning process certainly aren't very pleasant, and are presumably
>> carcinogenic. And yet, health authorities consistently recommend
>> cooking in cast iron as a way to increase dietary iron intake -- are
>> they simply overlooking the potential carcinogenic effects, or has it
>> been studied and found to be safe?
>
> Burning? Odors? You are doing something wrong if that is happening. Proper
> seasoning is when the heated oils polymerize. They change their physical
> state and seal the iron.

I have seen different advice on the proper temperature for seasoning.
Some sources say low temperatures of 300-350F, which would avoid
smoking with most oils. I found that to be less effective at creating
a nonstick surface than using a higher temperature, which causes some
smoking. Perhaps I should just stick (pun intended) with lower
temperatures? (I'm sure that time, the surface will still become more
nonstick with use.)


> POLYMERIZATION: a chemical reaction in which two or more molecules combine
> to form larger molecules that contain repeating structural units

That's a rather generic term. Many polymers are certainly
carcinogenic -- one type that might even be relevant in this context
would be the polycyclic aromatic hydrocarbons (PAHs), which have
received a lot of attention in the health press recently. (I'm not
entirely sure that PAHs would count as polymers, though.)


>> I'm not trying to be alarmist and tell people not to use cast iron.
>> I'm just curious and somewhat concerned.
>
> You seem to be very concerned about it though, and have no evidence to base
> anything about it. Borderline alarmist, IMO.

If I were being alarmist, I would have thrown out all my cast iron
(which I haven't), stormed into my neighbors' kitchens and thrown out
all their cast iron, and then posted to rec.food.equipment
(cross-posting to rec.food.cooking, sci.health.nuts, and alt.alarmism)
telling -- nay, commanding -- all of you good folks to throw out your
cast iron, and write your Congressperson to enact legislation to
create a Cast Iron Regulatory Oversight Council.

But I'm not telling anybody to do that. Instead, I posted a question,
admitting my ignorance about the subject and asking for information,
which I am grateful to have received in two separate responses. I am
indeed pleased that both responses seem to be saying very similar
things, and things which make sense to me, and do not cause me any
alarm.

--
Randall

"Randall Nortman" > wrote in message
nk.net...
> On 2005-12-14, Edwin Pawlowski > wrote:
>>
>> "Randall Nortman" > wrote in message
>> nk.net...
>>> This is something that's been bothering me for a while, but I can't
>>> find much information about it. When (non-enameled) cast iron gets
>>> seasoned, what exactly is happening chemically? What is that layer
>>> you're depositing on the iron? It seems to me that you're essentially
>>> burning oil and food particles onto the iron. Last time I checked,
>>> burned, smoked oil is believed to be carcinogenic. The fumes from the
>>> seasoning process certainly aren't very pleasant, and are presumably
>>> carcinogenic. And yet, health authorities consistently recommend
>>> cooking in cast iron as a way to increase dietary iron intake -- are
>>> they simply overlooking the potential carcinogenic effects, or has it
>>> been studied and found to be safe?
>>
>> Burning? Odors? You are doing something wrong if that is happening.
>> Proper
>> seasoning is when the heated oils polymerize. They change their physical
>> state and seal the iron.
>
> I have seen different advice on the proper temperature for seasoning.
> Some sources say low temperatures of 300-350F, which would avoid
> smoking with most oils. I found that to be less effective at creating
> a nonstick surface than using a higher temperature, which causes some
> smoking. Perhaps I should just stick (pun intended) with lower
> temperatures? (I'm sure that time, the surface will still become more
> nonstick with use.)
>
>
>> POLYMERIZATION: a chemical reaction in which two or more molecules
>> combine
>> to form larger molecules that contain repeating structural units
>
> That's a rather generic term. Many polymers are certainly
> carcinogenic -- one type that might even be relevant in this context
> would be the polycyclic aromatic hydrocarbons (PAHs), which have
> received a lot of attention in the health press recently. (I'm not
> entirely sure that PAHs would count as polymers, though.)
>
>
>>> I'm not trying to be alarmist and tell people not to use cast iron.
>>> I'm just curious and somewhat concerned.
>>
>> You seem to be very concerned about it though, and have no evidence to
>> base
>> anything about it. Borderline alarmist, IMO.
>
> If I were being alarmist, I would have thrown out all my cast iron
> (which I haven't), stormed into my neighbors' kitchens and thrown out
> all their cast iron, and then posted to rec.food.equipment
> (cross-posting to rec.food.cooking, sci.health.nuts, and alt.alarmism)
> telling -- nay, commanding -- all of you good folks to throw out your
> cast iron, and write your Congressperson to enact legislation to
> create a Cast Iron Regulatory Oversight Council.
>
> But I'm not telling anybody to do that. Instead, I posted a question,
> admitting my ignorance about the subject and asking for information,
> which I am grateful to have received in two separate responses. I am
> indeed pleased that both responses seem to be saying very similar
> things, and things which make sense to me, and do not cause me any
> alarm.
>
> --
> Randall

Remember that even the best seasoning on cast iron is not nonstick but
merely stick resistant. It will never equal good teflon, that's just asking
too much.


--
Peter Aitken

"Randall Nortman" > wrote in message
nk.net...
> On 2005-12-14, Edwin Pawlowski > wrote:
> >
> > "Randall Nortman" > wrote in message
> > nk.net...
> >> This is something that's been bothering me for a while, but I can't
> >> find much information about it. When (non-enameled) cast iron gets
> >> seasoned, what exactly is happening chemically? What is that layer
> >> you're depositing on the iron? It seems to me that you're essentially
> >> burning oil and food particles onto the iron. Last time I checked,
> >> burned, smoked oil is believed to be carcinogenic. The fumes from the
> >> seasoning process certainly aren't very pleasant, and are presumably
> >> carcinogenic. And yet, health authorities consistently recommend
> >> cooking in cast iron as a way to increase dietary iron intake -- are
> >> they simply overlooking the potential carcinogenic effects, or has it
> >> been studied and found to be safe?
> >
> > Burning? Odors? You are doing something wrong if that is happening.
Proper
> > seasoning is when the heated oils polymerize. They change their
physical
> > state and seal the iron.
>
> I have seen different advice on the proper temperature for seasoning.
> Some sources say low temperatures of 300-350F, which would avoid
> smoking with most oils. I found that to be less effective at creating
> a nonstick surface than using a higher temperature, which causes some
> smoking. Perhaps I should just stick (pun intended) with lower
> temperatures? (I'm sure that time, the surface will still become more
> nonstick with use.)
>
>
> > POLYMERIZATION: a chemical reaction in which two or more molecules
combine
> > to form larger molecules that contain repeating structural units
>
> That's a rather generic term. Many polymers are certainly
> carcinogenic -- one type that might even be relevant in this context
> would be the polycyclic aromatic hydrocarbons (PAHs), which have
> received a lot of attention in the health press recently. (I'm not
> entirely sure that PAHs would count as polymers, though.)
>
>
> >> I'm not trying to be alarmist and tell people not to use cast iron.
> >> I'm just curious and somewhat concerned.
> >
> > You seem to be very concerned about it though, and have no evidence to
base
> > anything about it. Borderline alarmist, IMO.
>
> If I were being alarmist, I would have thrown out all my cast iron
> (which I haven't), stormed into my neighbors' kitchens and thrown out
> all their cast iron, and then posted to rec.food.equipment
> (cross-posting to rec.food.cooking, sci.health.nuts, and alt.alarmism)
> telling -- nay, commanding -- all of you good folks to throw out your
> cast iron, and write your Congressperson to enact legislation to
> create a Cast Iron Regulatory Oversight Council.
>
> But I'm not telling anybody to do that. Instead, I posted a question,
> admitting my ignorance about the subject and asking for information,
> which I am grateful to have received in two separate responses. I am
> indeed pleased that both responses seem to be saying very similar
> things, and things which make sense to me, and do not cause me any
> alarm.
>

I got a cast iron skillet as a gift several years ago. Apparently somewhere
along the way any instructions where separated from the skillet. I know how
to season cast iron, so I wasn't concerned. I slathered it with shortening
and put it in a 350F, intending to leave it for several hours. About 45
minutes later my kitchen was filled with smoke. After the skillet cooled, I
found that it had been coated with what looked like a plastic coating,
presumably to prevent rusting in the store. The melted coating was a bitch
to remove.

Edwin Pawlowski > wrote:

> Burning? Odors? You are doing something wrong if that is happening. Proper
> seasoning is when the heated oils polymerize. They change their physical
> state and seal the iron.

> POLYMERIZATION: a chemical reaction in which two or more molecules combine
> to form larger molecules that contain repeating structural units

> You are assuming the fumes are carcinogenic, but in reality, there are no
> fumes in properly seasong of the iron.

Seeing your post, I was curious, so I asked someone who is in chemical
engineering. Shortening which is typically used in seasoning, is
saturated fat. Saturated fat contains no free bonds, and won't
polymerize, so I am confused.

My understanding of the whole seasoning process is it just causes the
oil to clog up all the pores in cast iron so it won't rust, and over
time and use, the oil build up and forms a layer.

Anyone know how long ago the practice of baking the cookware with oil
to season it started?

> wrote in message
...
> Edwin Pawlowski > wrote:
>
>> Burning? Odors? You are doing something wrong if that is happening.
>> Proper
>> seasoning is when the heated oils polymerize. They change their physical
>> state and seal the iron.
>
>> POLYMERIZATION: a chemical reaction in which two or more molecules
>> combine
>> to form larger molecules that contain repeating structural units
>
>> You are assuming the fumes are carcinogenic, but in reality, there are no
>> fumes in properly seasong of the iron.
>
> Seeing your post, I was curious, so I asked someone who is in chemical
> engineering. Shortening which is typically used in seasoning, is
> saturated fat. Saturated fat contains no free bonds, and won't
> polymerize, so I am confused.
>
> My understanding of the whole seasoning process is it just causes the
> oil to clog up all the pores in cast iron so it won't rust, and over
> time and use, the oil build up and forms a layer.
>
> Anyone know how long ago the practice of baking the cookware with oil
> to season it started?

The heat oxidizes the oils permitting them to polymerize. I suspect the
seasoning process was originally something that just happened in daily use.
The baking was developed as a shortcut.


--
Peter Aitken