Aquest cafè no és gaire fort.

Aquest means this for a masculine singular noun.

It agrees with cafè, which is masculine singular, so the match is:

• aquest cafè = this coffee
• aquesta tassa = this cup
• aquests cafès = these coffees
• aquestes tasses = these cups

It is used when the thing is close to the speaker, just like this in English.

Because aquest already functions as the determiner.

In English, you also say this coffee, not this the coffee. Catalan works the same way:

• aquest cafè = this coffee
• not aquest el cafè

So aquest replaces the article.

Catalan usually uses ser for qualities seen as characteristics, and estar for states or conditions.

Here, the sentence is describing the coffee’s strength as a quality, so ser is the normal choice:

• Aquest cafè no és gaire fort.

Using estar here would usually sound unnatural to most learners in standard usage.

A simple way to think about it:

• ser = what something is like
• estar = how something is at the moment / where something is

For coffee strength, Catalan normally treats it as a quality, so és is expected.

Here, gaire means something like very, especially, or particularly in a negative sentence.

So:

• no és gaire fort = not very strong

This is one of the most common uses of gaire in Catalan. It often appears with:

• negatives
• questions
• conditionals

Examples:

• No tinc gaire temps. = I don’t have much time.
• Tens gaire gana? = Are you very hungry? / Do you have much hunger?

Usually, in standard Catalan, gaire is most natural in negative or similar contexts.

So you commonly get:

• No és gaire fort.
• No en vull gaire.
• Tens gaire feina?

In a normal affirmative sentence, Catalan often prefers molt instead:

• És molt fort. = It’s very strong.

So as a learner, a safe rule is:

• use gaire mostly with no, in questions, and in similar contexts
• use molt in regular affirmative statements

Because in Catalan, no is placed before the conjugated verb to make the sentence negative.

So:

• és fort = it is strong
• no és fort = it is not strong

That is the normal position for negation in simple sentences.

Here:

• Aquest cafè no és gaire fort.

The structure is very straightforward:

• Aquest cafè = subject
• no és = negative verb
• gaire fort = complement

Here, fort means strong in the sense of flavor or intensity, which is very natural for coffee.

Catalan fort can also mean:

• physically strong
• loud
• intense
• severe

So the exact meaning depends on context.

In this sentence, it clearly refers to the coffee’s strength of taste.

Because fort has to agree with cafè, and cafè is masculine singular.

So the adjective also stays masculine singular:

• cafè fort = strong coffee

If the noun changed, the adjective would change too:

• beguda forta = strong drink
• cafès forts = strong coffees
• begudes fortes = strong drinks

So yes, adjectives in Catalan usually agree in gender and number with the noun they describe.

Both can suggest that the coffee is not strong, but no és gaire fort is the more natural and idiomatic choice in many everyday situations.

The nuance is roughly:

• no és gaire fort = it isn’t very strong
• és poc fort = it is a little weak / it has little strength

No és gaire fort often sounds softer and more conversational.
És poc fort can sound a bit more direct or analytical.

As a learner, no és gaire fort is an excellent phrase to remember.

They help with pronunciation and sometimes with meaning.

• és has an accent to distinguish it from es, which is a pronoun.
• cafè has an accent showing that the stress falls on the last syllable: ca-FÈ

So the sentence is stressed roughly like this:

• a-QUEST ca-FÈ no ÉS GAI-re FORT

Depending on the dialect, the exact vowel sounds can vary, but the written accents are important and should not be ignored.

Yes, but it means something slightly different.

• Aquest cafè no és gaire fort = this coffee isn’t very strong
• El cafè no és gaire fort = the coffee isn’t very strong

So aquest points to a specific coffee near the speaker or clearly being indicated.
El cafè is more like the coffee, referring to a known coffee in the situation.

Both are correct; they just do not point to the noun in exactly the same way.