Se você colocar muito açúcar, o café fica doce demais.

After se meaning if, Portuguese usually uses the future subjunctive when the condition is about a possible future action.

So in this sentence:

• Se você colocar muito açúcar... = If you put a lot of sugar...

With the verb colocar, the future subjunctive form is colocar, which looks exactly like the infinitive. That is why it may seem unusual at first.

A few examples:

• Se você fizer isso... = If you do that...
• Se você puder vir... = If you can come...
• Se você colocar açúcar... = If you put sugar...

Both are possible, but in this context add is the most natural English translation.

• colocar açúcar no café = to put/add sugar in the coffee

So Se você colocar muito açúcar... means If you add too much / a lot of sugar...

In everyday Brazilian Portuguese, colocar is very commonly used where English might prefer put or add, depending on the context.

Fica here means becomes, gets, or ends up being.

So:

• o café fica doce demais = the coffee gets too sweet / becomes too sweet

If you used é, it would sound more like you are describing the coffee as inherently sweet, not as the result of adding sugar.

Compare:

• O café é doce. = The coffee is sweet.
• O café fica doce. = The coffee becomes sweet / gets sweet.

In this sentence, the idea is a result of an action, so fica is the natural choice.

Portuguese often uses the present tense to express a general result or something that typically happens.

So:

• Se você colocar muito açúcar, o café fica doce demais.

means something like:

• If you add a lot of sugar, the coffee gets too sweet.

Using ficará is grammatically possible, but it sounds a bit more formal or more specifically future-oriented:

• Se você colocar muito açúcar, o café ficará doce demais.

In everyday Brazilian Portuguese, fica is more natural here.

Here, demais means too much or excessively.

So:

• doce demais = too sweet

It comes after the adjective:

• bonito demais = too beautiful / beautiful to an excessive degree
• caro demais = too expensive
• doce demais = too sweet

Be careful: demais can also mean a lot in some contexts, but here it clearly means too.

Because they are modifying different things:

• muito açúcar = a lot of sugar
• doce demais = too sweet

So the sentence is saying:

• if you add a lot of sugar,
• the coffee becomes too sweet

This is completely natural in Portuguese.

Also, note the nuance:

• muito açúcar = a large quantity of sugar
• açúcar demais = too much sugar

You could also say:

• Se você colocar açúcar demais, o café fica doce demais.

That version emphasizes too much sugar even more directly.

Because açúcar is normally treated as an uncountable noun here, like sugar in English.

So Portuguese uses:

• muito açúcar = a lot of sugar

not:

• muitos açúcares

You would only use a plural like açúcares in special contexts, such as talking about different types of sugars.

Sometimes yes, but Se você colocar... is clearer and more natural for many learners to use.

In Brazilian Portuguese, subject pronouns like você are often stated explicitly. If you say:

• Se colocar muito açúcar...

it may sound less clear without context, because colocar does not show the subject clearly by itself here.

So for a beginner or intermediate learner, Se você colocar... is the safer and more natural choice.

Because the sentence begins with a conditional clause:

• Se você colocar muito açúcar, ...

When the if-clause comes first, Portuguese normally separates it with a comma.

So this is standard:

• Se você colocar muito açúcar, o café fica doce demais.

If you reverse the order, the comma is often omitted:

• O café fica doce demais se você colocar muito açúcar.

Yes, absolutely. That is a perfectly natural sentence.

Both versions are correct:

• Se você colocar muito açúcar, o café fica doce demais.
• O café fica doce demais se você colocar muito açúcar.

The difference is mostly about emphasis:

• starting with Se você colocar... highlights the condition first
• starting with O café fica... highlights the result first

It does agree with café, but doce is one of those adjectives whose masculine and feminine singular forms are the same.

So:

• café doce = sweet coffee
• bebida doce = sweet drink

In the plural, it changes:

• cafés doces
• bebidas doces

So doce is already the correct agreeing form for singular café.

In this sentence, se clearly means if.

• Se você colocar muito açúcar... = If you put a lot of sugar...

But se can also have other uses in Portuguese, especially as a reflexive or impersonal particle. For example:

• Ele se machucou. = He hurt himself.
• Vende-se pão. = Bread is sold / Bread for sale.

So se has several jobs in Portuguese, but in your sentence it is simply the conjunction if.