Does sourdough bread require a hechsher?

Shalom!
Does sourdough bread from any bakery require a hechsher?
Thanks for your wonderful service.

What are the ingredients?

There are a few sourdough types. See below:

  1. Wheat flour (wheat flour, calcium carbonate, iron, niacin, thiamin), water, salt, rice flour, flour treatment agent (ascorbic acid), rapeseed oil, non declarable processing aid (enzymes).

  2. Fortified wheat flour (wheat flour, calcium carbonate, iron, niacin, thiamin), water, rye flour, salt, wholemeal wheat flour.

  3. Wheat flour, water, wheat fibre, salt, malted barley flour, vitamin D yeast.

  4. rye starter, dark rye flour, honey, molasses and crushed caraway seeds.

Thanks again!

The specific ingredients listed above are all kosher.

Thank you! Where can I buy Rav Abadi’s halachic works in English please?

Sorry! They aren’t printed in English yet

What are some of his Hebrew works that may be available for purchase?

Ohr Yitzchak 1 & 2
It should be available in some bookstores. If you don’t find let us know