Learn Hardcore Chinese: kāfēi suīrán yǒudiǎnr kǔ, dànshì tā xíguàn bù jiā táng hē. - Although coffee is a bit bitter, he is used to drinking it without sugar.

You can often drop one side:
- 虽然咖啡有点儿苦，他还是不加糖喝。
  (Although the coffee is a bit bitter, he still drinks it without sugar.) — dropped 但是
- 咖啡有点儿苦，但是他习惯不加糖喝。
  (The coffee is a bit bitter, but he’s used to drinking it without sugar.) — dropped 虽然

But in textbook / careful style, keeping both 虽然 and 但是 is very common and feels complete and clear, especially for learners.

Why is 虽然 placed after 咖啡 instead of at the very beginning?

Both of these are correct:

咖啡虽然有点儿苦，但是他习惯不加糖喝。
虽然咖啡有点儿苦，但是他习惯不加糖喝。

They differ only in focus:

虽然咖啡有点儿苦 …
Neutral; you introduce the whole idea “the coffee is a bit bitter” as the although part.
咖啡虽然有点儿苦 …
Puts slight emphasis on 咖啡 as the topic first: “As for the coffee, although it’s a bit bitter, …”

Both are very natural. Chinese often likes to state the topic first (咖啡 here), then add information about it, so version 1 feels very normal in conversation.

What does 有点儿 add here? Why not just say 咖啡苦?

咖啡苦。
“The coffee is bitter.” — neutral statement of fact.
咖啡有点儿苦。
“The coffee is a bit bitter / kind of bitter.”
有点儿 (yǒudiǎnr) usually:
- softens the description,
- often implies the speaker thinks it’s slightly too bitter or undesirable.

So 有点儿苦 suggests:

it’s a little on the bitter side, and
the bitterness is a slight negative, not just a neutral property.

That nuance is why 有点儿 is very common with “negative-ish” adjectives:
有点儿贵 (a bit expensive), 有点儿累 (a bit tired), 有点儿难 (a bit difficult), etc.

What is the difference between 有点儿 and 一点儿?

Roughly:

有点儿 + adjective → slightly negative or unwanted:
- 咖啡有点儿苦。
  The coffee is a bit too bitter (implied complaint / negative shade).
一点儿 + noun → a small quantity, neutral:
- 加一点儿糖。
  Add a little sugar.
一点儿 + adjective (often with 更 / 再 / 要) → small degree, usually neutral or positive:
- 再甜一点儿。
  Make it a bit sweeter.
- 便宜一点儿。
  Make it a bit cheaper.

In this sentence 有点儿苦 is appropriate because “bitter” is typically not a positive quality for most people, so you get that “slightly undesirable” nuance.

Why can we say 咖啡 … 苦 without 是? Why not 咖啡是苦?

Chinese does not use 是 (shì) before adjectives the same way English uses “to be”.

Patterns:

Noun + Adjective is directly “Noun is Adj”:
- 咖啡苦。 → The coffee is bitter.
- 天气冷。 → The weather is cold.
- 他很高。 → He is tall.

Using 是 with an adjective (e.g. 咖啡是苦的) is possible but adds a different feel:

咖啡是苦的。
More like you’re confirming or contrasting:
“The coffee is (indeed) bitter.” / “It is bitter (as opposed to sweet).”

In normal description, you don’t put 是 before an adjective; you just use Noun + Adjective or Noun + 很 + Adjective. So 咖啡有点儿苦 is the most natural here.

What’s the role of the 儿 in 有点儿? Can I drop it and just say 有点?

有点儿 (yǒudiǎnr) and 有点 (yǒudiǎn) mean essentially the same thing.
有点儿 is more typical in northern / standard spoken Mandarin.
In careful writing, you’ll often see 有点 without 儿:
- 这个问题有点复杂。

So:

有点儿苦 and 有点苦 both work in speech.
儿化 (adding 儿) is a phonetic/stylistic feature; it doesn’t change the grammar here.

For learners, it’s fine to use either; just be aware that in many textbooks aimed at spoken Mandarin, you’ll see 有点儿.

What exactly does 习惯 mean here, and how is it used grammatically?

In this sentence, 习惯 (xíguàn) is a verb meaning “to be used to / to be accustomed to”.

Structure:

Subject + 习惯 + Verb Phrase
→ Subject is used to doing that thing.

Examples:

他习惯早起。
He is used to getting up early.
我不习惯喝这么甜的咖啡。
I’m not used to drinking such sweet coffee.

So:

他习惯不加糖喝。
→ “He is used to drinking (it) without sugar.”

习惯 can also be a noun meaning “habit”:

这是他的习惯。
This is his habit.

But in your sentence it functions as a verb.

Why is the phrase 不加糖喝 in that order? Why not 不喝加糖的 or something similar?

不加糖喝 literally is:

不 – not
加糖 – add sugar
喝 – drink

Chinese often puts extra details of how you do something (like “with sugar / without sugar”) before the main verb:

他加糖喝咖啡。
He drinks coffee with sugar. (lit. he add-sugar drink coffee)
他不加糖喝咖啡。
He drinks coffee without sugar.

In your sentence, 咖啡 has already been mentioned, so it’s omitted at the end:

他习惯不加糖喝（咖啡）。
He is used to drinking (coffee) without sugar.

You could say 喝不加糖的咖啡, but:

不加糖喝 is shorter and very natural in everyday speech.
喝不加糖的咖啡 is slightly more explicit and maybe a bit more formal/neutral.

Both are grammatically correct; the original just uses the common verb phrase pattern: (不) + manner/detail + verb.

Why is there no object after 喝? Shouldn’t it be 喝咖啡?

The full idea is:

他习惯不加糖喝咖啡。

But since 咖啡 was already introduced at the beginning of the sentence, Chinese often omits repeated nouns when they’re clear from context.

So the sentence becomes:

咖啡虽然有点儿苦，但是他习惯不加糖喝。
(lit.) As for the coffee, although it’s a bit bitter, he is used to not adding sugar (when he) drinks (it).

This is a common topic–comment style:

Topic: 咖啡
Comment: although it’s a bit bitter, he is used to drinking it without sugar.

The object 咖啡 is understood and doesn’t need to be repeated.

Can we replace 但是 with 可是 or 不过? Are there differences?

Yes, you can replace 但是 with 可是 or 不过 here:

咖啡虽然有点儿苦，可是他习惯不加糖喝。
咖啡虽然有点儿苦，不过他习惯不加糖喝。

Rough tendencies:

但是 – slightly more formal / neutral; common in writing and speech.
可是 – very common in spoken Chinese; feels a bit more colloquial / emotional sometimes.
不过 – often means “however / but still”, with a slight “in spite of that” feel.

In this sentence, all three are acceptable; the meaning difference is very small. For learners, treating them all as “but / however” is fine, and using 但是 is a safe default.