Note: I misinterpreted the situation. I am afraid I read your question somewhat superficially, and assumed that we are talking about this answer for which I recently dismissed a not-an-answer flag (not even sure that the flag came from you). I only realized my mistake after almost completing my answer. As I think that the information I wrote is interesting for Seasoned Advicers, and that it fits the general question (how do we decide if something is an answer) even if it doesn't fit the example you linked, I will still post it, because I think that in this case, it is an answer :)
I dismissed your flag without taking an action, because I thought that the answer is OK as it is.
What we are trying to do is to have single question threads, where the body of answers is enough for the OP and any subsequent reader with the same problem to solve the problem. The rule that answers have to directly address the question is derived from this goal. We do not want answers which give advice on solving problems the OP does not have, since this is irrelevant for them. Canonical example: Somebody asks "why did my recipe for X produce an X which is too dry" and somebody else answers "This is my recipe for X and it always turns out great". What the OP is trying to do is to get their own recipe to work, or to gain knowledge how to tweak bad recipes into good ones. A different recipe does not solve their problem.
In the case we are talking about, the answer does indeed not fit the literal formulation of the question. The OP is asking how to save already-ruined food, and the answer explains how to avoid ruining it in the first place. So it does not answer the question-as-stated. But is it relevant to the problem the OP faces? I think that yes, it is. Sure, a cook can know how to make a given food right, but ruin a batch of it by mistake. But I think that it is a safe bet that many readers having the problem of having just cooked a lighter-fluid-tasting burger will be thankful to read information about how to cook their burgers without the lighter fluid taste next time. So, it still addresses part of the problem the OP has, even if it is not an answer to the sub-problem they are asking about. Therefore, it is an answer by the spirit of our rules, even if it hurts their letter under strict interpretation. It is probably not good enough to become the accepted answer, but it is relevant to the problem, and as such should be left for the other readers to see.
As a last word: I agree with what Jefromi said. If you think that an answer is so bad it should be removed, you can cast a flag.