Earlier in the same lesson I learned that matthias refered to (Koffer) as (er) given it is a masculine in (er ist nicht da) then sandra later refered to it as (ihn) in (Können sie ihn beschreiben). why haven't we remained consistent in the following sentence in the same lesson and begin the sentence with (Er) instead of (Es)????

            (Es ist ein großer schwarzer Koffer mit kleinen Rädern.)

thank you for your answer!

That's an interesting question that hadn't occurred to me.

I think if the sentence had been "It is black" then it would have been "Er ist schwarz" my grammar book is pretty clear on that. But is also says that "es" can be "he, she or it" without further explanation.
According to Duden's proof reader, both "er" and "es" are grammatically correct.
https://www.duden.de/rechtschreibpruefung-online

I wonder if "es" is preferred because the suitcase appears on the other side of "ist"? Could it be that "Er ist ein Koffer" would mean "he is a suitcase"?

It will be interesting to see what the tutor has to say.

Nothing from the tutor, so I asked my German friend and she said that she would definitely use "es" in the situation you described. However being a native speaker she couldn't say why, just that it sounds right.

Es ist ein großer schwarzer Koffer mit kleinen Rädern.

I appreciate the effort you've put in sir, I hope that the tutor's absence is due reasearching the matter. 
however such conclusion is unsatisfying, when should you start/stop refering to such object with es/er. I hope that future learning will make us pick up a pattern that helps us determine such thing.
let's just hope it is not an idiosyncrasy and there is a rule for such use of pronouns!
 

I think the answer must lie in whether the subject is present or not.
If we have been talking about  a suitcase and then we want to say "it is black "
the we use the pronoun  "er"to replace suitcase so it is "er ist schwarz". The "er" tells us that we are referring back to something masculine. It could be anything masculine but the context implies that it is the suitcase.
But in the actual sentence "Es ist ein großer schwarzer Koffer mit kleinen Rädern."
the subject - the suitcase - is present  so there is no doubt what we are describing and we use "es" to refer forward to the subject.
Google translate (not that reliable) translates "Er ist ein großer schwarzer Koffer mit kleinen Rädern." as He is a big black suitcase with small wheels. It would sound very odd to say that. :-)

Unfortunately my Collins easy German grammar doesn't go into an explanation of this particular situation. 


 

Hi Yahya and sfpugh,

If you said:
"My suitcase is big and black and has little wheels" in German, then the word "my" would have to be "mein" in order to agree with the gender of the word "suitcase", so it would be Mein Koffer ist schwarz und gross und hat kleine Räder.

In German you could also say:
Er ist gross und schwarz und hat kleine Räder. The "er" is referring to the suitcase.

However, there are ways to structure a sentence that don't require you to indicate the gender with Er ist or Sie ist.

For example, if someone has just had a baby and you asked them about the gender, they will either say Es ist ein Junge or Es ist ein Mädchen. 
You could argue that it should be Er ist ein Junge or Sie ist ein Mädchen, but Es ist... is a set expression and can be used with either gender.

Hope this helps!

Lucia

Is it safe to say, that in general we can use 'Es' to refer to inanimate subjects of either genders and keeping the gender consistent with animate subjects like humans, animals, etc.. ??

Thanks for the explanation, so it comes down to one of those things where "it's just what people say".
 

Hi Yahya,

Yes, in general expressions, such as the one above "es ist", indicating the gender is not required. This doesn't apply only to inanimate object though, because living beings are affected as well, like the baby example.

Lucia