In my grammar dictionary, it gives the example

> あのステーキはおいしそうだった

but under the notes it goes on to say that 「そうだ」 can not be used with regards
to past events or states.
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2018-03-27T01:57:14.217
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2022-01-24T03:03:35.337
2018-05-07T15:44:55.013
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question
word-choice tense
Is おいしそうだった grammatical?
When you describe "It looked like delicious" in Japanese, you can say like
「おいしそうだった。」.

i-Adj/na-Adj + そうだった = looked like (adjective)

Ex:  
**おいし** そうだった。 (i-Adjective)  
**悲{かな}し** そうだった。 (i-Adjective)  
**面白{おもしろ}** そうだった。 (i-Adjective)  
**便利{べんり}** そうだった。（Na-Adjective)  
**静{しず}か** そうだった。（Na-Adjective)
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2018-05-08T05:24:30.500
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2018-05-08T10:44:02.253
2018-05-08T10:44:02.253
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answer
To answer your original question in the title (tl;dr), **yes**. The phrase is
proper grammar.

Let's break this sentence up a bit:

> あのステーキは[美味]{おい}しそうだった。  
> That steak looked delicious.

What you're probably confused about was the そうだった part.

It's probably easier to look at the part after the particle by splitting it
into `adjective + 〜そう` _and then_ `だった`, which is the simple past form for だ.
Therefore, the above sentence is really just a past form for this:

> あのステーキは[美味]{おい}しそうだ。  
>  That steak looks delicious.

I think that the dictionary mentions the point of そうだ being inapplicable to
describing the past is probably because you'd then have to conjugate そうだ into
そうだった.

In addition, if you just look up `そうだ` in the dictionary, it can also be used
and understood as something along the lines of "that's right".
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2018-07-07T15:44:17.120
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answer