Eu prefiro o sabor do café sem açúcar.

Yes. In Brazilian Portuguese, you can often omit subject pronouns because the verb form already shows who is doing the action.

So:

• Eu prefiro o sabor do café sem açúcar.
• Prefiro o sabor do café sem açúcar.

Both are correct.

Including Eu adds emphasis, contrast, or clarity. For example, Eu prefiro... can sound like I prefer... as opposed to someone else.

Because preferir is an irregular verb.

The first-person singular present form is:

• eu prefiro = I prefer

Not prefero.

Some present-tense forms of preferir are:

• eu prefiro
• você / ele / ela prefere
• nós preferimos
• vocês / eles / elas preferem

A useful thing to notice is that preferir behaves a bit like pedir and some other -ir verbs that change in certain forms.

Preferir directly means to prefer, so it is the most direct match for English here.

• Eu prefiro o sabor do café sem açúcar. = I prefer the taste of coffee without sugar.

You might also hear:

• Gosto mais de café sem açúcar. = I like coffee without sugar more.

That is also natural, but it is not exactly the same structure.
A key grammar point is:

• preferir usually takes a direct object: prefiro o sabor...
• gostar usually takes de: gosto de café...

Because sabor is a masculine singular noun, and Portuguese often uses the definite article where English may or may not use the.

• o sabor = the taste/flavor

In Portuguese, articles are used very frequently, especially with nouns in general statements or when talking about something in a more specific way.

So o sabor do café sem açúcar sounds very natural.

Because do is a contraction of:

• de + o = do

So:

• o sabor do café literally = the taste of the coffee

This contraction is extremely common in Portuguese.

Other common ones are:

• de + a = da
• de + os = dos
• de + as = das

So do café is not a separate word to memorize by itself; it is the normal contracted form.

Good question. The two parts work differently.

1. do café

Here, café is inside a de + noun structure:

• o sabor do café = the taste of coffee / the taste of the coffee

Portuguese often uses the article in this kind of phrase.

2. sem açúcar

After sem (without), Portuguese often uses a noun with no article when speaking generally:

• sem açúcar = without sugar

That is the normal, natural form.

If you said sem o açúcar, it would usually mean something more specific, like without the sugar—a particular sugar already mentioned or understood.

In this sentence, it is understood as describing café:

• o sabor do café sem açúcar = the taste of coffee without sugar

So the idea is that the coffee is unsweetened.

In practice, this is how a Brazilian listener will normally understand it. The phrase sounds natural.

If you want to make it even more explicit, you could also say:

• Eu prefiro o sabor do café quando está sem açúcar.
• Eu prefiro o sabor do café sem colocar açúcar.

But the original sentence is perfectly fine.

Mostly, yes.

Sabor can often be translated as:

• taste
• flavor

In this sentence, either works well in English.

• o sabor do café = the taste of coffee
• o sabor do café = the flavor of coffee

Portuguese does not always make the same distinction English sometimes makes between taste and flavor.

Yes, it is natural and correct.

That said, in everyday conversation, Brazilians might also say simpler versions such as:

• Eu prefiro café sem açúcar.
• Prefiro café sem açúcar.
• Gosto mais de café sem açúcar.

Your original sentence sounds a little more focused on the taste/flavor, which makes it slightly more descriptive.

Yes, a little.

The most neutral version is:

• Eu prefiro o sabor do café sem açúcar.

You can also omit Eu:

• Prefiro o sabor do café sem açúcar.

You generally would not want to move sem açúcar too far away, because it belongs with café.

For example, Eu prefiro sem açúcar o sabor do café sounds unnatural.

So while Portuguese allows some flexibility, this original order is the best and most natural here.

A simple pronunciation guide:

• prefiro ≈ preh-FEE-roo
• café ≈ kah-FEH
• açúcar ≈ ah-SOO-kar or ah-SOO-car depending on accent

A few helpful notes:

• The é in café is stressed.
• The ç in açúcar sounds like s, never like k.
• In Brazilian Portuguese, final o in prefiro is often pronounced like a short u sound, so it may sound a bit like prefiru.

Because both marks show important pronunciation information.

ç

The ç is called cedilha.
It makes the c sound like s before a, o, or u.

So:

• açúcar starts with an s sound in the middle: a-SU-car

Without the cedilla, acúcar would suggest a different sound and would be incorrect.

Accent mark

The accent in açúcar helps mark the stressed syllable and follows Portuguese spelling rules.

These written accents are important in Portuguese and should be learned as part of the word.

Not in this sentence if you want the same meaning.

• sem açúcar = without sugar
• doce = sweet

These are different ideas.

For example:

• café sem açúcar = coffee with no sugar added
• café doce = sweet coffee

So Eu prefiro o sabor do café sem açúcar means you prefer coffee in its unsweetened form, not sweet coffee.

It breaks down like this:

• Eu = subject
• prefiro = verb
• o sabor do café sem açúcar = direct object

Inside the object:

• o sabor = the taste/flavor
• do café = of the coffee / of coffee
• sem açúcar = without sugar

So the core pattern is:

• Eu prefiro + noun phrase

This is a very useful structure you can reuse:

• Eu prefiro o chá sem leite.
• Eu prefiro a pizza sem cebola.
• Eu prefiro o sabor da fruta natural.