The sentence I want to translate is:
The wine cellar should be dark and dry.
Which of the following would be more appropriate and why?
La bodega debe ser oscura y seca.
La bodega debe estar oscura y seca.
In my opinion, it should be the first one, but actually, it could be both depending on the case.
I guess that wine cellars, in general, have to be
In the other hand, if this was not the case, and if you were talking about a specific moment for the
This is because you are talking about a specific moment (in time) of the house. It is not how houses are supposed to be, it is how they are in a certain period of time. If we change the example a bit again:
It is a state, not a specific moment.
P.S.: Note the gender of the adjectives in the examples,
I have to say that, thinking deeply about this, this is what you will find most (like 90%) of times (for any example, not just this one). It is true that some people may use the second sentence as a translation for your question. I think that they would mean that
The other answers point out an ambiguity in your original sentence: when should the cellar be dark and dry?
I'd rephrase the original question as
That translates cleanly to
and I think it's a sentence you're more likely to actually hear when talking about wine cellars. Otherwise, if the original sentence belongs to a longer paragraph, I'd want to read the context to know how to better translate. Perhaps the text gives a general sense of the time. E.g., in instructions for building or cleaning a wine cellar, the "always" is implied. Finally, though it might be fine to say
it's not a sentence that I'd ever write, because "dryness" is not an inherent quality of a cellar, but something that you have to make an effort to obtain.
Think of "ser" as a inherent property of the subject, and "estar" as a temporal property.
So if somebody "is handsome" can be "es guapo" or "está guapo", the first meaning he is a handsome person always and the second one that he looks handsome at that moment.
That's a good occasion to use the verb "permanecer". Otherwise, in spanish, "ser" is used as a way to describe the long-run state, while "estar" is used for short-run, varying properties. Similarly we use "estar" when we describe what we now do ("estoy pensando"), while we use "ser" for inherent properties and actions of the subject.