Das Bier ist kalt.

Because Bier is a neuter noun in German. Its dictionary form is das Bier.

German nouns have grammatical gender:

• der = masculine
• die = feminine
• das = neuter

So in the nominative singular (the basic subject form), Bier takes das.

Ist is the third-person singular form of the verb sein (to be).

The verb sein is irregular:

• ich bin = I am
• du bist = you are
• er/sie/es ist = he/she/it is

Since das Bier is a singular noun, German uses ist:

• Das Bier ist kalt.

Because kalt is being used as a predicate adjective here — it comes after the verb sein.

In German, adjectives usually have no ending when they come after verbs like:

• sein = to be
• werden = to become
• bleiben = to remain

So:

• Das Bier ist kalt. = The beer is cold.

But when an adjective comes before a noun, it usually takes an ending:

• das kalte Bier = the cold beer

So compare:

• das kalte Bier = adjective before the noun, so it gets an ending
• Das Bier ist kalt. = adjective after ist, so no ending

This is normal German main clause word order.

German main clauses typically put the conjugated verb in second position:

1. Das Bier = subject
2. ist = conjugated verb
3. kalt = complement/adjective

So the pattern is:

• Subject + verb + rest

This is very similar to English:

• The beer is cold.

Because all nouns are capitalized in German.

So:

• das Bier
• der Mann
• die Frau
• das Haus

Adjectives like kalt are normally not capitalized unless they begin a sentence or are being used as nouns.

In this sentence, das is the definite article meaning the:

• das Bier = the beer

German das can also mean that in other contexts, but not here.
Here it belongs directly to the noun Bier, so it is clearly the article.

Usually, no — not in a normal sentence like this.

German generally needs an article with singular countable nouns, and even many mass nouns often use one in ordinary statements. So:

• Das Bier ist kalt. = normal

Without the article, Bier ist kalt sounds incomplete or unnatural in most everyday contexts.

That said, article-less nouns can appear in special cases, such as headlines, labels, recipes, or very general statements, but a learner should treat Das Bier ist kalt as the standard form here.

A simple approximate pronunciation for an English speaker is:

dahs beer ist kahlt

A few helpful points:

• das: the a is like a in father
• Bier: sounds roughly like beer
• ist: short i, like i in bit
• kalt: the a is again like a in father, and the t is clearly pronounced

A rough IPA version is: [das biːɐ̯ ɪst kalt]

Its basic meaning is cold, especially for temperature:

• Das Bier ist kalt. = The beer is cold.

But like English cold, it can also be used more broadly in other contexts, for example:

• kaltes Wetter = cold weather
• eine kalte Stimme = a cold voice
• kalter Kaffee = cold coffee

In this sentence, though, the meaning is the straightforward physical one: the beer has a low temperature.

Yes, but the meaning changes slightly.

• kalt = cold
• kühl = cool / pleasantly cool / not very warm

So:

• Das Bier ist kalt. = The beer is cold.
• Das Bier ist kühl. = The beer is cool.

For beer, both can work, but kalt is the more direct translation of cold.