Why do pyrolytic ovens require the removal of metal racks for cleaning?

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Discussion Overview

The discussion revolves around the reasons for removing metal racks from pyrolytic ovens during the self-cleaning cycle. Participants explore the implications of high temperatures on the racks, including potential warping, discoloration, and damage to the oven's interior components. The conversation includes personal experiences and alternative cleaning methods.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants express confusion about the necessity of removing metal racks, questioning whether the temperatures in pyrolytic cleaning can actually affect stainless steel.
  • Samsung's guidance indicates that metal racks may warp and discolor due to extreme heat, and that they could potentially damage the oven's porcelain cavity due to thermal expansion.
  • One participant notes that they have not experienced any warping or discoloration after using the self-cleaning function without removing the racks, suggesting variability in outcomes.
  • Another participant speculates that the design of the oven and racks may account for differential expansion, which could mitigate warping issues.
  • Several participants share alternative cleaning methods, such as using steam or ammonia, and discuss their effectiveness compared to pyrolytic cleaning.
  • Concerns are raised about the potential for thermal shock to damage the enamel surface of the oven during alternative cleaning methods.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the necessity of removing racks during pyrolytic cleaning, with some agreeing with the manufacturer's warnings while others report no issues from leaving them in. The discussion remains unresolved regarding the best practices for cleaning and the actual risks involved.

Contextual Notes

Participants mention various assumptions about the materials used in ovens and the thermal properties of stainless steel and enamel, but these assumptions are not universally agreed upon. There is also a lack of empirical evidence provided to support claims about damage or effectiveness of cleaning methods.

Who May Find This Useful

Individuals interested in home appliance maintenance, particularly those using pyrolytic ovens or exploring alternative cleaning methods for kitchen equipment.

sophiecentaur
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TL;DR
Why do you need to take out the furniture and racks during pyrolytic cleaning
I just tried cleaning our new oven with the pyrolytic function. Incredible results and it certainly warmed up the house.

But the intructions insisted that I remove all metal racks etc. I have to wonder why, bearing in mind that the temperature can't melt the stainless steel. This increases the effort from minimal to annoyingly much. Would the heating affect the silvery finish of the S/S or could it possibly affect the strength?

Having scolded someone about not making an effort to research a topic, I'm a bit reluctant to post this question but the videos and text that Google offer me are all about the how's and not the why's.

The temperature of the oven seems to be lower than what could affect t S/S (?).
 
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From Samsung:
  • We do not recommend leaving the oven racks in the oven during the self-clean cycle. The racks may warp and discolor due to the extreme heat created during this cycle. The racks can also damage the rack guides of the porcelain oven cavity due to expansion and contraction.
 
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renormalize said:
From Samsung:
  • We do not recommend leaving the oven racks in the oven during the self-clean cycle. The racks may warp and discolor due to the extreme heat created during this cycle. The racks can also damage the rack guides of the porcelain oven cavity due to expansion and contraction.
From the horse's mouth, as they say. Thanks.
I guess a suitable metal for the oven contents would triple the price.

I wouldn't mind a change of colour but warping could be an embarrassment.
 
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+ SS cleaner & microfiber dry wipe
 
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sophiecentaur said:
From the horse's mouth, as they say. Thanks.
I guess a suitable metal for the oven contents would triple the price.

I wouldn't mind a change of colour but warping could be an embarrassment.
 
sophiecentaur said:
But the intructions insisted that I remove all metal racks etc.
Same with ours. I did that the first time but never since.
renormalize said:
The racks may warp and discolor due to the extreme heat created during this cycle. The racks can also damage the rack guides of the porcelain oven cavity due to expansion and contraction.
This has not happened. Yet. YMMV.
 
pbuk said:
Same with ours. I did that the first time but never since.

This has not happened. Yet. YMMV.
That's nice to know.

I guess the distortion could be taken care of if the mounting holes / slots are designed generously. It's not absolute expansion here but differential expansion, compared with the oven body that counts. There's the problem. I imagine that the steel of the oven must have been chosen to match the enamel or there would be cracking under normal thermal cycling. This wiki link has a list of typical expansion figures. I'm sure the designers used similar information - steel to match the enamel being more important than matching stainless steel.

Probably Smeg (and the other manufacturers) are just covering their backsides. We have to wait for more input from PF about experiences. If it still looks risky, I might remove the grot on the metalwork with a blow torch, carefully applied.

But what a potential selling point to offer a self cleaning oven that looks after itself!!
 
sophiecentaur said:
We have to wait for more input from PF about experiences.
Probably better forums for this: in the UK we have Mumsnet. Some reports of damage there.
 
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I don't know about currently manufactured ovens, but the older ones (without fancy "coatings") had a rather convenient approach to cleaning, even the gas ovens.

Heat them up to their maximum temperature, then, using a pump squirt bottle (spray bottle set to 'stream'), squirt the heavy crud layers with water. The steam explosion and sudden temperature change does an amazing cleaning job.

You would probably want to remove the racks first just to get them out of the way.

Have Fun!
Tom

p.s. Probably want to avoid the heating elements/burner. I haven't damaged any yet but ...
 
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pbuk said:
Probably better forums for this: in the UK we have Mumsnet. Some reports of damage there.
A good suggestion except that their posts didn't discuss any actual Science. No one actually said that being naughty caused any breakage - just slightly discoloured shelves.

I did learn the idea of using the dishwasher for the S/S furniture. I also got the message that sloppy people, who wait a long time between cleanings, suffer from a stinky kitchen whilst the self cleaning is in progressing. Serve 'em right, I say.

The inside ends up looking like a brand new oven.
 
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Tom.G said:
The steam explosion and sudden temperature change does an amazing cleaning job.
I wonder if the thermal shock could be damaging the enamel surface. I guess there's not a big temperature change below the surface and the coefficients of thermal expansion will be chosen to be similar.

From your description, it sounds like you have your underpants on outside your trousers.
 
  • #12
sophiecentaur said:
From your description, it sounds like you have your underpants on outside your trousers.
Ah well, I guess it all depends on whether you want to be 'practical' or 'conventional.' :wink:
 
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A suggestion re racks. i put all racks and any enamel oven trays I want to clean in a tough plastic bag (eg garden bag), pour in a couple of tablespoons of ordinary household ammonia, and close the bag. Leave for a day or so. The ammonia vapour saponifies the grease, which then comes off the racks etc nicely in the dishwasher. You can use the bag again and again, to save wasting more plastic.
 
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  • #14
old school chemistry said:
A suggestion re racks. i put all racks and any enamel oven trays I want to clean in a tough plastic bag (eg garden bag), pour in a couple of tablespoons of ordinary household ammonia, and close the bag. Leave for a day or so. The ammonia vapour saponifies the grease, which then comes off the racks etc nicely in the dishwasher. You can use the bag again and again, to save wasting more plastic.
Actually, the pyrolytic cleaning takes no effort so I tend to do it more frequently. Hence the racks are cleaner and the grot tends to soak off in the sink with just washing up liquid. In the old days, I used a heavy duty oven cleaner and they supplied hefty bags to do your trick with. Single use, of course.

I considered risking the racks in the oven but warping could be a problem, soluble only with a good flat surface and a big hammer (and crossed fingers).