Se puseres fermento a mais, o bolo cresce demasiado e pode cair.

After se when we talk about a future possibility, Portuguese normally uses the future subjunctive.

So:

• se puseres = if you put
• not se pões, which sounds like a general present statement
• not usually se vais pôr, which is less natural in this kind of conditional sentence

Here, puseres is the tu form of the future subjunctive of pôr.

A useful pattern is:

• Se + future subjunctive, present/future result

For example:

• Se estudares, passas.
• Se chover, ficamos em casa.
• Se puseres fermento a mais, o bolo cresce demasiado.

Because it comes from the verb pôr (to put), which is irregular.

Its future subjunctive is based on the stem puser-:

• se eu puser
• se tu puseres
• se ele/ela você puser
• se nós pusermos
• se vocês eles elas puserem

So puseres is simply the tu form.

This verb is worth memorising because it appears a lot:

• ponho = I put
• pões = you put
• pôs = he/she put
• pus = I put / I placed
• se puseres = if you put

Yes. In Portugal, tu is very common in everyday speech, so learners of European Portuguese see forms like puseres often.

The sentence has an implied tu:

• Se puseres fermento a mais... = If you put too much baking powder/raising agent...

If the sentence used você, it would be:

• Se puser fermento a mais...

In European Portuguese, tu forms are important and very common, so it is useful to get comfortable with them early.

Literally, fermento can refer to a leavening agent, so the exact English word depends on context.

In a sentence about cake (bolo), fermento usually means baking powder rather than yeast.

So in this context, an English speaker would normally understand it as:

• baking powder or more generally
• raising agent

If someone specifically means yeast, they may say:

• fermento de padeiro

And for baking powder, you may also see:

• fermento em pó

A mais means too much, more than necessary, or extra.

So:

• fermento a mais = too much baking powder
• literally, something like baking powder in excess

You will see a mais in many similar phrases:

• sal a mais = too much salt
• açúcar a mais = too much sugar
• dinheiro a mais = extra money / money in excess

It often follows the noun:

• pus sal a mais
• compraste coisas a mais
• há gente a mais aqui

Portuguese often omits the article when talking about a substance in a general, non-specific way.

So:

• puseres fermento a mais = if you put too much baking powder not necessarily
• if you put too much of the baking powder

Using no article sounds natural because fermento is being treated as a material or ingredient in general.

You could sometimes hear:

• Se puseres demasiado fermento...

That is also natural, but the version with fermento a mais is very common and idiomatic.

Portuguese often uses the present tense to express a future result when the meaning is clear from context.

So:

• Se puseres fermento a mais, o bolo cresce demasiado literally looks like If you put too much baking powder, the cake grows too much but it naturally means
• If you put too much baking powder, the cake will rise too much

This is very common in Portuguese:

• Se comeres muito, ficas mal.
• Se saíres agora, apanhas trânsito.

English often prefers will, but Portuguese very often uses the present tense in these result clauses.

Cresce is the conjugated verb:

• o bolo cresce = the cake rises/grows

Crescer is the infinitive:

• crescer = to grow / to rise

In this sentence, we need the conjugated form because the subject is o bolo:

• o bolo cresce

In cooking contexts, crescer can mean to rise, not just to grow in a general sense.

So for dough or cake:

• a massa cresce
• o bolo cresce

Here demasiado means too much or excessively.

So:

• cresce demasiado = rises too much

In European Portuguese, demasiado is very standard and natural in this kind of sentence.

You may also know demais, but it does not always work in exactly the same way, and learners often overuse it. For this sentence, demasiado is the safer and more idiomatic choice in European Portuguese.

Useful comparison:

• demasiado = excessively / too much
• demais can sometimes mean too much, but also has other uses depending on context

For a learner of Portuguese from Portugal, cresce demasiado is the form to remember.

In this context, cair means the cake can collapse, sink, or fall in after rising too much.

So:

• pode cair = it may collapse / sink

Portuguese uses cair very naturally here, even though English often prefers a more specific verb like:

• collapse
• sink
• fall flat

So the idea is:

• too much raising agent makes the cake rise too much
• then it loses structure
• and it cai

Because the speaker is expressing possibility, not certainty.

• pode cair = it can collapse / it may collapse
• cai = it collapses / it will collapse

Using pode makes the sentence more careful and realistic: too much baking powder often causes a problem, but not in absolutely every case.

So the sentence means:

• if you put too much baking powder, the cake rises too much and may collapse

Yes. That is perfectly natural.

• pôr fermento = to put/add baking powder
• colocar fermento = to place/add baking powder

Both work, but they feel slightly different:

• pôr is very common and everyday
• colocar is a bit more formal or neutral

So these are both fine:

• Se puseres fermento a mais...
• Se colocares fermento a mais...

In spoken European Portuguese, pôr is extremely common.

Grammatically, crescer does mean to grow, so grows too much is not wrong.

But in a baking context, English usually says:

• rises too much

So:

• o bolo cresce demasiado
  is best understood in natural English as
• the cake rises too much

This is a good example where the most literal translation is not the most natural one.

It can function as all three, depending on context, but most naturally it sounds like a warning/explanation.

It has the structure of a general cause-and-effect statement:

• If you put too much baking powder, the cake rises too much and may collapse.

So it can be used:

• as cooking advice
• as an explanation of what happens
• as a warning about a mistake to avoid

This kind of sentence is very common in Portuguese for practical instructions and everyday explanations.