Because tipos in the sense of types is a masculine noun, with no feminine form. Also, since tipos is the noun being quantified here, the quantifier muitos needs to agree with it in gender and number. If instead of “muitos tipos de cerveja”, you had written “muitas cervejas”, the quantified noun would be cervejas and the quantifier would agree with it.
I noticed that that’s what you were going for, many times (present continuous - estar a), but in those cases where I made corrections, it didn’t fit as well as the past participle, in my opinion. There’s not actually much to explain here, because the same logic applies as in English.
Take a look at this bit, for example:
- “O wort fica a cozinhar por mais 5 ou 10 minutos. Finalmente, o wort é drenado de novo”.
If we translate it, we get something like:
- “The wort is left cooking for another 5 or 10 minutes. Finally, the wort is drained again”.
In the first sentence, as you can see, a continuous form of the verb can fit well, both in Portuguese and in English, because the action itself has a prolonged duration (…5-10 minutes). Even here, you don’t have a real present continuous, because
you’re not talking about something happening right now; you’re just describing a procedure. Hence the “is left cooking” instead of just “is cooking” (in English), and the choice of the verb ficar - fica a cozinhar - instead of estar - está a cozinhar (in Portuguese).
In the second sentence, this vague sense of continuity doesn’t seem to fit well in neither of the languages.
This is a matter of active vs. passive voice. That is, if the subject is the one performing the action or if the action is performed unto it.
An example of active voice: “o fabricante de cerveja tem de molhar a cevada”
How this would be in a passive voice: “a cevada tem de ser molhada pelo fabricante de cerveja”
Hah, the temporary vs. permanent rule isn’t applicable to everything. It’s just one of a few different guiding principles to choose between ser vs. estar, depending on context. I don’t know if you’ve read this topic, but it goes a little bit deeper into that: Ser ou Estar ... quando usar?
In this case, it’s just about the general rules for using the past participle. We use estar to describe the state of something at that moment (without implying any continuity), and ser to describe a state with a certain continuity, as well as actions to be taken or just general information. It’s easier to show you examples of the latter first, and then contrast those with examples of the former:
Ser + past participle
- A seguir, a refeição é aquecida no microondas. = Then, the meal is heated in the microwave. (Action to be taken - e.g. steps of a recipe)
- O livro é feito de papel. = The book is made of paper. (General info)
- O estacionamento é proibido aqui. = Parking is forbidden here. (A supposedly prolonged condition)
Estar + past participle
- A refeição está aquecida. = The meal is heated. = The meal is warm. (Current state - e.g. right after taking it out of the microwave)
- O livro está feito. = The book is made. = The book is ready. (Current state - e.g. right after printing it)
- O estacionamento está proibido aqui. = Parking is forbidden here. (Current and supposedly temporary condition - e.g. due to temporary road works)