Aquesta melmelada té un gust molt dolç perquè hi ha massa sucre.

Because melmelada is a feminine singular noun, and the demonstrative has to agree with it.

• aquest = this, masculine singular
• aquesta = this, feminine singular
• aquests = these, masculine plural
• aquestes = these, feminine plural

So:

• aquesta melmelada = this jam

Té is the 3rd person singular form of tenir = to have.

The accent is important because it distinguishes té from te:

• té = has
• te = tea

So Aquesta melmelada té... means This jam has...

Both are possible, but they are slightly different in focus.

• té un gust molt dolç = it has a very sweet taste
• és molt dolça = it is very sweet

The sentence with gust focuses more specifically on the taste/flavor. This is a very natural way to talk about food in Catalan.

Because dolç describes gust, not melmelada.

In un gust molt dolç:

• gust is masculine singular
• so the adjective must also be masculine singular: dolç

Compare:

• Aquesta melmelada és molt dolça. → dolça agrees with melmelada
• Aquesta melmelada té un gust molt dolç. → dolç agrees with gust

Here, gust means taste or flavor.

So té un gust molt dolç literally means has a very sweet taste.

Be careful: gust can also mean liking or pleasure in other contexts, but in food-related sentences it often means taste/flavor.

Here perquè means because.

It is written as one word and with an accent when it introduces a reason:

• perquè = because

This is different from per què, which usually means why or for what reason:

• Per què és tan dolça? = Why is it so sweet?
• És tan dolça perquè hi ha massa sucre. = It is so sweet because there is too much sugar.

Hi ha means there is or there are.

It is a very common Catalan expression used to talk about existence or presence.

• hi ha sucre = there is sugar
• hi ha moltes pomes = there are many apples

Even though hi looks like a separate word, in this expression you should usually learn hi ha as a fixed unit meaning there is/there are.

Because massa means too much, while molt means a lot of.

• molt sucre = a lot of sugar
• massa sucre = too much sugar

In this sentence, the idea is that the jam is overly sweet because the amount of sugar is excessive, so massa is the right choice.

Because sucre is being used as an uncountable noun in a general quantity expression.

In Catalan, after words like massa, molt, poc, and similar quantity words, you normally use the noun directly:

• massa sucre
• molt pa
• poca sal

You would use an article only if you were referring to something specific, such as el sucre de la recepta.

Because in Catalan, descriptive adjectives are often placed after the noun.

So:

• un gust dolç = a sweet taste

This is the normal order. Some adjectives can go before the noun, but that often changes the nuance or sounds more literary or emphatic. For a basic food description, gust molt dolç is the natural pattern.

No. In this sentence, massa means too much, but it can have other uses too.

For example:

• as a quantity word: massa sucre = too much sugar
• as an adverb: És massa dolça = It is too sweet
• as a noun in other contexts: massa can also mean dough or mixture

So the meaning depends on the context. Here it clearly means too much.