What Makes Dishes and Containers "Dishwasher Safe"? "Microwave Safe"?

[Duvel]

17 hours ago, weinoo said:

I think if something is microwave safe, these home dishwashers can't really damage them.

In principle you are right from temperature aspect. From my point of view, dishwasher safe includes the resistance to hot alkaline environments (whereas microwave safe relates to the temperature alone), so I‘d make a small distinction. 

[weinoo]

4 hours ago, Duvel said:

In principle you are right from temperature aspect. From my point of view, dishwasher safe includes the resistance to hot alkaline environments (whereas microwave safe relates to the temperature alone), so I‘d make a small distinction. 

 

Thanks - didn't even think about the detergent/rinse stuff that goes on during a wash.  When I see "top shelf" dishwasher safe, I have to assume they're referring to heat vs. chemical reaction; the chemical reaction I assume takes place no matter where the item is located during the wash.

 

I guess many dishwashers have their heating elements on the bottom; I remember my mom's crappy dishwasher did, and it probably got pretty hot in order to dry stuff. Whereas the Miele here dries stuff in a totally different way...from residual heat?

[Duvel]

1 minute ago, weinoo said:

 

Thanks - didn't even think about the detergent/rinse stuff that goes on during a wash.  When I see "top shelf" dishwasher safe, I have to assume they're referring to heat vs. chemical reaction; the chemical reaction I assume takes place no matter where the item is located during the wash.

 

I guess many dishwashers have their heating elements on the bottom; I remember my mom's crappy dishwasher did, and it probably got pretty hot in order to dry stuff. Whereas the Miele here dries stuff in a totally different way...from residual heat?

Part of my job used to be material science, especially corrosion phenomena, so it‘s a way of predefined thinking for me 🙄

 

I was actually wondering about the „top shelf“ distinction. I have never seen that type of statement in Germany. The dishwasher I have (a pretty standard one from Siemens) has a separate heating element to regulate the water temperature of the water going into the dishwasher directly. It seems some older models (80‘s, if my father remembers correctly) used to have heating could in the bottom, but they were discontinued.

 

Does the top element in „your“ dishwashers get significantly hotter than the desired water temperatures of lats say 60-70 oC ?

[Duvel]

10 minutes ago, weinoo said:

When I see "top shelf" dishwasher safe, I have to assume they're referring to heat vs. chemical reaction; the chemical reaction I assume takes place no matter where the item is located during the wash.

And just to add (the nerdy bit): there are two types of „cleaning chemistries“ going on typically.

 

There is an alkaline component, that dissolves fats and proteins very effectively and with exponential performance depending on temperature. The higher temperature cycles rely on this component. It is corrosive and causes damage to unsuited plastics and blinds cheap glass. 

 

Then there is an enzymatic component (in high end detergents), that works well in warm up to 40 oC environments. It takes a bit longer to dissolve all matters, and its action is usually promoted in the „eco“ cleaning cycle of your machine. This is also the basic idea behind the „dishwasher tab in your sink/toilet/drain“ hack …
 

[weinoo]

Good question - I don't even know where the heating elements are!

 

Here's the manual page on temps...

 

 

I'd say 99% of the time, I'm running it on normal cycle.

 

 

 

[Anna N]

1 hour ago, Duvel said:

I was actually wondering about the „top shelf“ distinction. I have never seen that type of statement in Germany.

Yes the earlier model dishwashers had a heating coil in the bottom very much like what you see in the oven. If plastic fell onto this it would melt. Some plastic would deform if too close to it. Hence the warning to put plastic on the top rack. 

[ElsieD]

3 hours ago, Duvel said:

This is also the basic idea behind the „dishwasher tab in your sink/toilet/drain“ hack …

 

 

What is this "hack"?  I've never heard of it.

[Duvel]

1 hour ago, ElsieD said:

 

What is this "hack"?  I've never heard of it.

These dishwasher tabs (actually all dishwasher detergents) are „designed“ to dissolve organic residues. So naturally, they do clean toilets, drains etc. pretty, pretty well - especially if you let them soak for a while. And they are friendlier to the material (steel etc.) than the hard cleaners …
 

 

[Margaret Pilgrim]

1 hour ago, Duvel said:

These dishwasher tabs (actually all dishwasher detergents) are „designed“ to dissolve organic residues. So naturally, they do clean toilets, drains etc. pretty, pretty well - especially if you let them soak for a while. And they are friendlier to the material (steel etc.) than the hard cleaners …
 

 

Dishwasher detergent is my accomplice.     A tablespoon in a baked on disaster + boiling water + an overnight rest = a half-hour disagreeable work avoided.

[FauxPas]

13 hours ago, weinoo said:

Good question - I don't even know where the heating elements are!

 

You may not have any heating elements in your dishwasher. Newer ones often don't, as the old-style heating element is not very energy efficient and don't really work well with newer energy efficiency standards. If you had an element, you'd most likely be able to see it. Mine is pretty visible. 

 

My current KitchenAid (about 8 years old) does still have a heating element in the bottom, but it's an optional function and I never use it. I just open the door and let things finish drying that way. Most things are dry anyway, it's just the plastic stuff that is usually still a bit wet. 

 

Condensation drying is the usual alternative to heated drying:

 

The final rinse uses high-temperature water to make the dishes very hot.

The stainless steel tub of the dishwasher cools faster than your dishes because stainless steel cools faster than glass and porcelain.

Condensation occurs when the moist air in the dishwasher comes into contact with the cooler stainless steel tub, and turns into water droplets. These water droplets trickle down to the bottom of the dishwashers and are drained.

 

https://www.bosch-home.com/us/experience-bosch/tips-and-tricks/all-articles/tips-to-maximize-drying

 

 

The final rinse cycle in mine is indeed hot, so I guess it essentially dries by condensation when I don't use the optional heat cycle. 😀

 

Is your machine a Miele? Here are notes on drying in those machines, looks like some have fans, similar to a convection oven. 

https://advanceappliance.com/blog/miele-dishwasher-leaves-dishes-wet/

 

Edited July 19, 2021 by FauxPas
to add Miele info (log)

[weinoo]

11 hours ago, FauxPas said:

Is your machine a Miele? Here are notes on drying in those machines, looks like some have fans, similar to a convection oven. 

 

Yes...and it has a little fan.

 

I often do what you do, and try to open the door when the cycle is finished.  The only stuff which isn't fully dry is the plastic, so after I unload the rest of the dishwasher (bottom up!), that comes out onto a towel on the counter. Works fine for me.

[blue_dolphin]

I have a 2-drawer style dishwasher (Fisher-Paykel) so basically just one shelf per drawer.  Whenever I see those "top shelf dishwasher safe" labels I just throw it in and hope for the best.  No heating element in the bottom so I think I'm safe.