Assalam o Alaikum, we have already posted on our website that jar for making vinegar should have a neck-type / smaller mouth as compared to its bottom.
We need a slow fermentation, the shape of jar which you have shown is not good.
See the other jars picture in which we have pomegranate vinegar, this shape is the best.
Please read the procedure for making dates vinegar in the link above.
Is it ok to use this jar to make dates vinegar?
If so, do i fill to the rim of the jar?