Fermentation- Rust issues

[Watsnikfaye]

Hi,
Need some help here!!
Just fermented a nice batch of beets and carrots (along with ground yellow mustard, asafoetida )only to open and find some rust on the lid. It’s been fermenting for 5 days now. Wanted to know if I can consume it or is this toxic because of the rust . I’d hate to throw this away .

 

[Indian_villager]

Is that mold I'm seeing? If it is mold, I wouldn't mess with it.

 

[MikeCo]

The acidity in the veggies and/or mustard likely caused rust. A plastic lid is generally better for fermenting vegetables. If the veggies contacted the rust, I think it's best to discard them.

 

[IslandLizard]

Is that lid regular steel or stainless steel?
Generally, stainless steel should not rust, but some alloys may.
That jar looks like a kitchen type storage jar, so odds are the lid is not designed for damp environments or be exposed to acidic (or alkaline) solutions, such as encountered during fermentations.

Here's a test:
Does a magnet stick to it? If it doesn't stick, it's most likely stainless steel.
However, if the magnet sticks it's inconclusive.

I'm not convinced it's rust. It may just be some discoloration. Rust usually has a characteristic tell/smell. Use your nose.

You could probably taste some of the brown stuff and if it tastes metallic or just putrid, you may have your answer.
Spit it out, rinse your mouth out well, and probably discard the batch.

You need to clean the lid anyway, so if you see any lasting rusty or discolored areas on the lid, its probably wise to discard the batch.

 

[MikeCo]

Stainless can rust in saline or acidic environments. Best to use a jar with a plastic lid.