Glasurbrenningen begynner med en gang glasuren og keramikkovnen er klare.

Because Norwegian usually writes compound nouns as a single word.

Here, glasurbrenningen is built like this:

• glasur = glaze
• brenning = firing / burning
• -en = the definite singular ending

So:

• glasurbrenning = glaze firing
• glasurbrenningen = the glaze firing

A useful rule is that the last part of a Norwegian compound is the main noun. That is the part that decides the gender and how the word is inflected.

In Norwegian, definiteness is usually shown by adding an ending to the noun, rather than by using a separate word like the.

So:

• glasur → glasuren
• keramikkovn → keramikkovnen

This is one of the biggest differences from English. English says the glaze and the ceramic kiln, but Norwegian often puts the the idea at the end of the noun instead.

Also, these nouns are definite because the sentence is talking about the specific glaze and the specific kiln involved in that process, not just any glaze or any kiln.

Because in simple noun phrases, Norwegian normally uses the definite ending by itself.

So you get:

• glasuren
• keramikkovnen

not a separate article before them.

A separate article such as den, det, or de is usually added when there is an adjective:

• glasuren = the glaze
• den klare glasuren = the ready/clear glaze

So the sentence is normal Norwegian: the definiteness is already built into the noun.

Here, med en gang means as soon as or immediately once.

This expression can be used in two closely related ways:

• Kom hit med en gang! = Come here immediately!
• ... med en gang glasuren ... er klare = ... as soon as the glaze ... are ready

So in this sentence, it introduces the idea of something happening right after a condition is met.

Because Norwegian often uses the present tense for:

• general facts
• instructions
• process descriptions
• things that happen regularly or by rule

So Glasurbrenningen begynner ... is a normal way to describe how the process works.

English can do the same thing:

• The glaze firing begins as soon as ...

So this is not necessarily talking about one specific moment happening right now. It can also describe a general procedure.

Because the subject is plural in meaning:

• glasuren og keramikkovnen = the glaze and the ceramic kiln

Two things joined by og act as a plural subject, so the adjective must also be plural.

The adjective klar changes like this:

• klar = singular, common gender
• klart = singular, neuter
• klare = plural

So:

• glasuren er klar
• keramikkovnen er klar
• glasuren og keramikkovnen er klare

Because that part is a subordinate clause.

In Norwegian, main clauses usually follow the V2 rule, where the verb comes in the second position. But subordinate clauses usually do not use that pattern. They normally keep subject + verb order.

So here:

• main clause: Glasurbrenningen begynner ...
• subordinate clause: glasuren og keramikkovnen er klare

That is why you do not get something like er glasuren og keramikkovnen klare in this sentence.

Brenning is a noun related to the verb å brenne.

In everyday language, å brenne often means to burn, but in pottery and ceramics, brenning usually means firing in a kiln.

So in this sentence, brenning is a technical/process noun, not just ordinary burning in the everyday sense.

For the same reason as glasurbrenningen: Norwegian strongly prefers single-word compounds.

So:

• keramikk
  • ovn = keramikkovn
• keramikkovnen = the ceramic kiln

English often writes similar expressions as two words, but Norwegian usually combines them into one. This is very common, and getting used to it is important when reading Norwegian.