How big and leafy was this stem that it was able to block an airgap ? And, how did it even make it through the filter(s) in the first place.

You could solve your problem by Scraping the large junk off your plates into the trash or disposal and then putting them in the DW. No stems in the airgap and plenty of bits left for the enzymes to eat.

Airgaps are ugly anyway and Claif. is the only locale I know that is a stickler about them. And yes , I know the UPC's stance. A high loop of the drain hose will do almost the same thing for no cost and you won't have a wart on your countertop.

You could also get a miele DW which has a built in check valve that negates the need for either.

The airgaps are simple to replace - if you can get to them. It will all depend on your cabinet and sink size and how much room you have to get your mitts up there.

Why would anyone replace an airgap because it got clogged??? They are made so you can take them apart and clean them.
I even explain to customers that have them how they can do it over the phone when they call.
Pull off the cover by pulling straight up then you will see either a screw off cap or a clipped in cap that needs to come off. After removing the cap you will see a smaller tube inside a larger tube. The smaller tube comes from the d/w and the larger tube goes to the disposer or drain pipe. If clogged you will usually see the debris stuck in the smaller tube. I also instruct to place a cup or a glass over the airgap while it's apart and while holding down the cup start the dishwasher. The first cycle of every d/w is a drain cycle. This will flush out any remaining debris. Remember to hold down the cup or it could fly off. Then just reassenmble the air gap.

As I said it's simple and easy with no need to replace the air gap device.

Why would anyone replace an airgap because it got clogged??? They are made so you can take them apart and clean them. Repair services love to overblow situations for pulling more fundage.

Bosch DWs do not have any type of 'garbage disposer/grinder' in many (if not a)ll) models.

They rely on filters.

You should check your filter in the bottom of the DW for clogging or a hole.

Nothing big enough to bother an air gap should have gotten past the filter.

There might be a misunderstanding of the Bosch filtering system.

The Bosch filters out the debris from the wash water so it isn't sprayed back onto the dishes. All the small particles are then flushed out the drain. The center round filter has a large item trap that will catch a toothpick, bone, etc in it's baffles but the center goes straight to the drain.

I'd think a stem large enough to block an airgap would have been trapped down there with the toothpicks, bones , and the ect....

Still puzzled by this one.