El café me sabe un poco amargo hoy, y el yogur está demasiado agrio para mí.

Because saber can be used with an indirect object pronoun to mean to taste to someone.

So:

• El café sabe amargo = The coffee tastes bitter.
• El café me sabe amargo = The coffee tastes bitter to me.

Adding me makes it more personal and subjective. It is like saying it tastes bitter to me or I find it bitter.

Saber has more than one meaning.

The two most common are:

• saber + information/fact = to know
  
  • Sé la respuesta. = I know the answer.
• saber + adjective / noun phrase = to taste
  
  • La sopa sabe bien. = The soup tastes good.
  • El café me sabe amargo. = The coffee tastes bitter to me.

So the meaning depends on the structure around the verb.

Both are possible, but they are not exactly the same.

• El yogur está agrio focuses on the yogurt’s state or condition: it is sour, possibly too sour, maybe even going off.
• El yogur me sabe agrio focuses more on how it tastes to me.

In this sentence, está demasiado agrio sounds very natural because yogurt being sour can describe its current condition, not just the speaker’s perception.

So:

• me sabe amargo = a personal taste impression
• está demasiado agrio = its current state is too sour

They describe different kinds of unpleasant taste:

• amargo = bitter
• agrio = sour

Examples:

• café amargo = bitter coffee
• limón agrio = sour lemon
• yogur agrio = sour yogurt

For this sentence, amargo fits coffee very naturally, and agrio fits yogurt very naturally.

Para mí means for me, to me, or in my opinion / to my taste.

In this sentence, it softens the statement and shows that this is the speaker’s personal reaction:

• El yogur está demasiado agrio. = The yogurt is too sour.
• El yogur está demasiado agrio para mí. = The yogurt is too sour for me / for my taste.

So it does not necessarily mean the yogurt is objectively bad. It may simply be too sour for that person.

Because the two clauses use different structures.

First clause

• El café me sabe amargo
• Pattern: something + me/te/le... + sabe + adjective

This structure naturally takes an indirect object pronoun.

Second clause

• El yogur está demasiado agrio para mí
• Pattern: something + está + adjective + para mí

With estar, Spanish normally does not use me in the same way here.
You would not usually say El yogur me está agrio for this meaning.

If you wanted to use me, you would normally switch back to saber:

• El yogur me sabe demasiado agrio.

Because they agree with the nouns they describe:

• el café is masculine singular, so amargo
• el yogur is masculine singular, so agrio

If the noun were feminine, the adjective would change:

• la leche está agria
• la bebida me sabe amarga

Spanish adjectives usually agree in gender and number with the noun or subject they refer to.

Spanish often uses the definite article more than English does, especially with foods, drinks, and things that are understood from context.

So:

• El café me sabe un poco amargo hoy can mean The coffee tastes a bit bitter today, often referring to the coffee I’m drinking now.
• El yogur está demasiado agrio para mí can mean The yogurt is too sour for me, referring to a specific yogurt or serving.

Using el here is normal and idiomatic.

Yes. Both are possible, but the nuance changes a little.

• El café está amargo = The coffee is bitter.
• El café me sabe amargo = The coffee tastes bitter to me.

The version with me sabe sounds more personal and sensory.

Likewise:

• El yogur está agrio = The yogurt is sour.
• El yogur me sabe agrio = The yogurt tastes sour to me.

In your sentence, the writer chooses two slightly different ways of expressing taste:

• one more subjective with me sabe
• one more descriptive/state-based with está

Un poco means a little, a bit.

It modifies the adjective:

• un poco amargo = a little bitter

This is the normal order:

• un poco + adjective
• demasiado + adjective

So:

• un poco amargo = a bit bitter
• demasiado agrio = too sour

Yes. Hoy is quite flexible.

The original sentence:

• El café me sabe un poco amargo hoy

Other natural possibilities include:

• Hoy el café me sabe un poco amargo.
• El café hoy me sabe un poco amargo.

The meaning stays basically the same. The original version sounds very natural and puts hoy at the end for a light contrast, as if the coffee tastes different today than usual.

Yes. Yogur is a very normal and common form in Spain.

You may also see:

• yogurt

But yogur is very standard in Spain and often feels more traditional in everyday Spanish.