New microwave misting up?

Draeger · 15 Jan 2017 at 11:54

We just bought a new microwave, a Swan SM22100B after our old one packed in. I've used it a few times since we got it and the glass on the door always seems to mist up quite considerably during use? Having Googled this it seems that as per usual there are people who say that this is normal and others who say its not supposed to happen.

Anyone know if its something I should be concerned about? I'm in two minds whether to take it back or not.

Tuppy_Glossop · 15 Jan 2017 at 12:03

The door will mist if the temperature of the glass/plastic is lower than the temperature inside the microwave. It probably says more about the temp in your kitchen than a problem with your microwave.

Draeger · 15 Jan 2017 at 14:01

Tuppy_Glossop said:
The door will mist if the temperature of the glass/plastic is lower than the temperature inside the microwave.

Won't that always be the case, temp outside the microwave will always be lower than inside? :confused:

Tuppy_Glossop · 15 Jan 2017 at 14:11

No. Microwaves only excite polar molecules, ie. not air.

tom_e · 15 Jan 2017 at 14:14

Tuppy_Glossop said:
No. Microwaves only excite polar molecules, ie. not air.

Yet the stuff being warmed up can and does warm the air in the microwave, cook something and open the microwave you'll feel the warm air.

Tuppy_Glossop · 16 Jan 2017 at 09:06

Yes, but it usually isn't so hot that you can't put your hands in to take the dish out of the microwave... normally it's the temp of the bowl itself that stops you, rather than the air temp in the microwave.

tom_e · 16 Jan 2017 at 09:17

Tuppy_Glossop said:
Yes, but it usually isn't so hot that you can't put your hands in to take the dish out of the microwave... normally it's the temp of the bowl itself that stops you, rather than the air temp in the microwave.

The air doesn't need to be scorching to cause enough of a differential to cause misting which was the original point.

krooton · 16 Jan 2017 at 09:37

All my microwaves have misted up when cookings things with higher mositure content as that water eventually steams out.

Hotwired · 16 Jan 2017 at 09:47

You're boiling the water in the food, turns to steam, condenses if a surface is cold enough. Normal stuff in a microwave if you boil off enough water into steam.

What was happening to the condensation in your old microwave.

Tuppy_Glossop · 16 Jan 2017 at 10:04

tom_e said:
The air doesn't need to be scorching to cause enough of a differential to cause misting which was the original point.

I know, it was my point after all

I was just explaining that the air in the microwave isn't *always* hot enough to cause condensation (as the op asked in post #3).

ci_newman · 16 Jan 2017 at 10:18

My microwave always mists up when cooking wet food. (i.e. high water content). I would be more worried about why it didn't happen with your old microwave, i.e. was there enough gaps in the door to allow water and rogue microwaves to escape?

Ch3m1c4L · 30 Jan 2017 at 11:23

https://www.youtube.com/watch?v=CQGW46B6x_4&ab_channel=DonutKnow

Atari · 30 Jan 2017 at 11:50

Our ridiculously old Panasonic one doesn't mist up ever. The only time it does is if some numpty has put something over the vent on top, or it's too close to the walls around it.

neil_g · 30 Jan 2017 at 12:38

Our Swan microwave condensates pretty badly too. You'd expect water vapour to escape through the vents in the top.

Causes problems if you don't leave the door open after use to allow it to dry out, as ours has now gone rusty in the bottom where water has pooled.

Need to contact Swan warranty dept and get it replaced.