Lägg inte juicen i frysen, för då blir den för kall.

Lägg is the imperative form of the verb lägga (to put / to place).

• att lägga = to put
• lägger = put / is putting
• lade / la = put (past)
• lägg! = put!

So Lägg inte juicen i frysen means Don’t put the juice in the freezer.

In a negative command, Swedish normally puts inte directly after the imperative verb:

• Lägg inte ... = Don’t put ...
• Gå inte dit. = Don’t go there.
• Öppna inte dörren. = Don’t open the door.

So Lägg inte juicen i frysen is the normal way to say Don’t put the juice in the freezer.

The -en ending is the definite singular ending for many common-gender nouns.

• juice = juice

• juicen = the juice

• frys = freezer
• frysen = the freezer

Swedish usually adds the definite article to the end of the noun instead of putting a separate word before it.

Compare:

• en juice = a juice

• juicen = the juice

• en frys = a freezer
• frysen = the freezer

Because juice is a common-gender noun in Swedish: en juice.

Common-gender nouns are referred to with den:

• juicen → den

Neuter nouns (ett nouns) use det instead:

• ett äpple → det

So in this sentence, den refers back to juicen.

Here, för means because / for.

So:

• ..., för då blir den för kall.
• ..., because then it becomes too cold.

This can be confusing because för also has other meanings in Swedish, such as:

• for / too in för kall = too cold
• for in expressions like en present för dig = a present for you

So in this sentence, för appears twice with two different meanings:

1. för = because
2. för kall = too cold

Here då means then / in that case / if that happens.

So:

• för då blir den för kall
• because then it gets too cold
• or more naturally: because otherwise it’ll get too cold if you do that

In this sentence, då points to the result of putting the juice in the freezer.

Because blir means becomes / gets, while är means is.

• den är kall = it is cold
• den blir kall = it gets / becomes cold

In the sentence, the juice is not cold yet, but it will become too cold if you put it in the freezer. That is why Swedish uses blir.

Because kall agrees with den, which refers to a common-gender singular noun.

Adjectives after är/blir often match the gender/number of the noun:

• den är kall = it is cold
• det är kallt = it is cold
• de är kalla = they are cold

Since juicen is an en-word, the correct form is:

• den blir för kall

not:

• den blir för kallt

It means too cold.

This is a very common use of för + adjective in Swedish:

• för varm = too warm
• för dyr = too expensive
• för svårt = too difficult

So för kall means the juice would become colder than is desirable.

Yes, literally i frysen is in the freezer, but Swedish often uses i where English would use in or into, depending on context.

With a verb of movement like lägga (put), Swedish i can naturally express the idea of putting something into something:

• lägga boken i väskan = put the book in/into the bag
• ställa mjölken i kylskåpet = put the milk in/into the fridge

So Lägg inte juicen i frysen is exactly what you would expect in Swedish.

Usually, the simple version Lägg inte juicen i frysen is the most natural here.

Sometimes Swedish can use extra directional words like in, but in this sentence they are not needed, because i frysen already makes the destination clear.

So for a learner, the best version to remember is:

• Lägg inte juicen i frysen

The comma separates the main instruction from the explanation:

• Lägg inte juicen i frysen,
• för då blir den för kall.

In Swedish, commas before conjunctions like för can appear when the writer wants to mark a clear pause. In everyday writing, comma use can vary a bit, but this punctuation is completely natural.

Yes. Juice is a normal Swedish word, borrowed from English/French long ago. In Swedish it is usually pronounced more like juus than English juice.

It behaves like a regular Swedish noun:

• en juice
• juicen
• juicer (juices)
• juicerna (the juices)

So even though it looks familiar to an English speaker, it still follows Swedish grammar.

In theory, den could refer to any common-gender noun, but in this sentence it clearly refers to juicen.

Why?

Because the meaning of the second clause is about what happens to the juice if you put it in the freezer:

• ... då blir den för kall = ... then it gets too cold

A freezer does not normally become too cold in this context, but juice does. So the listener naturally understands den as juicen.

You can, but it may sound a little stiff in English.

A close word-for-word translation is:

• for then it becomes too cold

A more natural English translation is often:

• because then it gets too cold
• because it’ll get too cold

So the Swedish structure is straightforward, but the best English wording may be slightly different.