Der Trommelröster erhitzt die Rösttrommel.

Because the two nouns have different grammatical genders:

• der Trommelröster is masculine
• die Rösttrommel is feminine

In German, every noun has a grammatical gender, and the article changes accordingly. This does not necessarily mean the thing itself is male or female in a real-world sense. It is just part of how the noun behaves grammatically.

In this sentence, the forms are also helping show the case:

• der = masculine nominative
• die = feminine accusative here

So the articles tell you both gender and grammatical role.

The subject is der Trommelröster and the direct object is die Rösttrommel.

You can tell this from the articles and the verb:

• der Trommelröster is in the nominative case, which usually marks the subject
• die Rösttrommel is in the accusative case, which often marks the direct object

So the structure is:

• Der Trommelröster = the thing doing the action
• erhitzt = the action
• die Rösttrommel = the thing receiving the action

In English, word order usually tells you this. In German, case endings and articles do a lot of that work.

erhitzt is the third-person singular present tense form of erhitzen, which means to heat up or to heat.

The verb forms are:

• ich erhitze
• du erhitzt
• er/sie/es erhitzt
• wir erhitzen
• ihr erhitzt
• sie/Sie erhitzen

Since der Trommelröster is a singular subject, German uses erhitzt.

Because German main clauses usually follow the verb-second rule, often called V2.

In a normal statement, the finite verb comes in the second position:

• Der Trommelröster | erhitzt | die Rösttrommel

That is very typical German word order.

Even if you move something else to the front, the verb still usually stays second:

• Die Rösttrommel erhitzt der Trommelröster.

That sentence is less neutral, but it still follows the V2 rule: the verb erhitzt is still in second position.

German often creates compound nouns by joining smaller words together.

Here:

• Trommelröster = Trommel
  • Röster
• Rösttrommel = Röst
  • Trommel

A very useful rule is: the last part is the main noun.

So:

• Trommelröster is a kind of Röster (roaster), specifically a drum roaster
• Rösttrommel is a kind of Trommel (drum), specifically a roasting drum

This is one of the most important skills in reading German technical or formal vocabulary.

Because in German, all nouns are capitalized, not just proper names.

So in this sentence:

• Trommelröster is capitalized
• Rösttrommel is capitalized

This is completely standard in German and helps readers quickly spot nouns in a sentence.

The letter ö is an umlaut vowel. English does not have an exact equivalent, but it is somewhat similar to:

• the vowel in French deux
• or the vowel in British pronunciations of bird without the strong r

A rough learner trick is:

1. Say ay as in say
2. Round your lips while trying to keep that tongue position

That will get you closer to ö.

Also note:

• Röst- and Röster both contain this sound
• it is different from plain o

If you cannot type ö, German often writes it as oe:

• Roesttrommel
• Trommelroester

But when possible, use ö.

Both are related to heating, but erhitzen usually means to heat something up or to make something hot more directly.

• heizen often means to heat in the sense of supplying heat, as with a building or room
• erhitzen more clearly expresses that something becomes hot through the action

So in a technical sentence about a machine heating a drum, erhitzt sounds very natural.

Yes, but the effect can change.

The neutral version is:

• Der Trommelröster erhitzt die Rösttrommel.

You could also say:

• Die Rösttrommel erhitzt der Trommelröster.

This still means the same thing, because the articles show who is doing what. But the focus changes. Starting with die Rösttrommel puts more attention on the roasting drum.

So German word order is more flexible than English, but it is not random. Changing the order often changes emphasis or style.

Because for feminine singular nouns, the article die is the same in both the nominative and accusative cases.

So:

• nominative feminine: die
• accusative feminine: die

That means the form itself does not change here. You understand the role from the whole sentence:

• der Trommelröster is nominative masculine
• die Rösttrommel is accusative feminine

This is one reason learners often need to learn articles together with gender and case patterns.

Yes. Both contain the idea of roasting:

• Röster = roaster
• Rösttrommel = roasting drum

This is common in German technical language: related parts of a process or machine often use the same root repeatedly. That can actually help you learn vocabulary, because once you know rösten means to roast, you can recognize related words more easily:

• der Röster
• die Röstung
• die Rösttrommel

So noticing repeated roots is a very useful learning strategy.