Pickled onions ends go black

[MD1]

Hi,
We've pickled some shallots and onions this year from our allotment and followed all the right steps. They taste fine but the ends where they have been cut have turned black.
We have made pickled onions previously using the same method and they all turned out fine.
Any ideas what has caused this blackness on the ends to occur so we can aviod in future?
Thanks,

[valmarg]

I presume you mean the root end of the onions.

We've had them turn dark, I wouldn't exactly say black.

If they taste fine, and are still nice and crunchy, I wouldn't bother too much.

If you are worried, you can always cut that bit off.

valmarg