Ef bragðið er of súrt, getum við bætt smá sykri í sósuna.

The basic noun is bragð, which means taste or flavor and is a neuter noun.

The ending -ið is the suffixed definite article, so:

• bragð = taste / flavor
• bragðið = the taste / the flavor

Icelandic usually puts the at the end of the noun instead of using a separate word like English does.

Because the adjective has to agree with bragðið.

Here, bragðið is:

• neuter
• singular
• nominative

So the adjective súr becomes the neuter singular form súrt.

This is very common in Icelandic after vera (to be):

• Kaffið er heitt = The coffee is hot
• Mjólkin er köld = The milk is cold
• bragðið er of súrt = the taste is too sour

Here of means too or excessively.

So:

• of súrt = too sour

That is different from mjög súrt, which would mean very sour.

So of usually signals that something is more than is desirable or acceptable.

This is because Icelandic main clauses normally follow a verb-second pattern.

The sentence begins with the subordinate clause:

Ef bragðið er of súrt, ...

That whole clause takes the first position. Then, in the main clause, the finite verb comes next:

• getum = second position
• við = subject, after the verb

So:

• Ef bragðið er of súrt, getum við ...

If the main clause stood alone, you would normally say:

• Við getum bætt smá sykri í sósuna.

Because after ef (if), Icelandic uses normal subordinate-clause word order.

So the subject comes before the verb:

• Ef bragðið er of súrt = If the taste is too sour

The inversion happens in the main clause after that, not inside the ef clause.

After modal verbs like geta (can / be able to), Icelandic commonly uses the supine form of the main verb.

For bæta, that form is bætt.

So:

• getum bætt = can add

This is a pattern learners often just have to get used to, because it does not match English very closely.

Because the verb pattern here requires the thing being added to be in the dative.

The noun is:

• sykur = nominative
• sykri = dative

With bæta in this meaning, Icelandic commonly uses:

• bæta einhverju í eitthvað
• literally: add something-dative into/to something

So smá sykri means a little sugar, with sykri in the dative.

Because the preposition í can take either accusative or dative, depending on the meaning.

• accusative: motion, direction, or change into/to
• dative: location in

Here the idea is adding something into/to the sauce, so Icelandic uses the accusative:

• í sósuna

If you said í sósunni, that would sound more like in the sauce as a location.

Also, sósuna is the definite accusative singular of sósa:

• sósa = sauce
• sósuna = the sauce

Because smá is often used as an indeclinable word meaning a little, a bit of, or some.

That means smá itself usually stays the same, even when the noun after it changes case.

So here:

• smá stays smá
• sykur changes to sykri

That is why you get:

• smá sykri

not a separately inflected form of smá.

Yes. In cooking and many other everyday contexts, bæta einhverju í eitthvað is a very natural pattern.

So:

• bæta smá sykri í sósuna = add a little sugar to the sauce

A useful way to remember it is:

• thing added → often dative
• container / mixture / target after í

This is a very common Icelandic structure, especially in recipes and kitchen instructions.