Can kashrus be judged by ingredients lists?

Question

I was googling hechsherim and ended up on oheltorah.com. It seems to contain a forum of people posting ingredient lists for products and admins judging whether or not the given product was kosher, for example, this or this. My initial reflex would be to say that this is not consistent with any mainstream Orthodox approach to Kashrus.

Looking into the authorship of the website, it seems to be produced by the children of a R Yitzchak Abadi, who is a talmid of R Aaron Kotler. Wikipedia:

oheltorah.com - A kashrut and halachah website by Rabbi Abadi's sons, including a Q&A forum answered "according to the opinions of their father, Rabbi Yitzchak Abadi."

Am I missing something? Does anyone hold that you judge kashrut based on ingredient lists with no actual supervision of the making of the product?

Answer 1

Basically, it depends on the product. Meat has to be slaughtered and prepared by observant Jews. Grape juice or wine can only be touched by observant Jews before pasteurization. Certain cooked foods require an observant Jew to perform the cooking (or according to Ashkenazi custom, to turn on the fire before cooking), etc. In these cases, knowing the ingredients is not enough, one also needs to know that the proper rules were followed.

Some foods do not have these requirements, and one just needs to ensure that all the ingredients are kosher. However, many foods have ingredients that are not listed explicitly on the label (often in the context of catch-all terms like "flavorings"). Some ingredients (e.g. glycerin) can be made from both kosher and non-kosher sources. It requires expertise in kashrus to know which kinds of foods can be determined to be kosher from the label and which can't.

In my personal experience, rabbis involved in kashrus are willing to look at a label. Sometimes they say the product is kosher, and sometimes they tell you to verify some information with the company that makes it. And sometimes they tell you you need to get product with a hechsher.

Certain products are known to not be problematic and require no hechsher, such as unflavored water and seltzer, extra-virgin olive oil, etc.

And some products might not need a hechser but require examination at home, such as many vegetables that need to be checked for insect infestation.

Answer 2

The simple answer giving by kashrut organizations is no. Many industrially-manufactured products go through complex production processes, at times unexpected. For instance R Elefant, the COO of OU Kosher, said that in some cases, the same steam pipe is used to heat vegetables in one industrial pot, and pork and beans in another, with the hot steam pipe connecting the two ! (listen here at 22'10 - incidentally much of that interview is relevant to your question).

So a box of "green beans, water and salt" might end up being non-kosher.

This being said, some ingredients are known for not requiring a hechsher, e.g., salt, sugar, water, cold-pressed virgin oil. See here and there for sample lists of such ingredients.

As indicated in the comments, expert kashrut supervisors often know products, how and where they were produced, and can advise on whether they are indeed kosher. But it shouldn't be tried by an untrained consumer serious about kashrut.