Тесто расстаивали вплоть до того, что подъём теста остановился.

Here расстаивали is a baking term. It comes from расстаивать and means to let dough rise, to proof dough, or to leave dough for fermentation before baking.

So Тесто расстаивали means something like:

• They were proofing the dough
• The dough was left to proof
• The dough was proofed

Because тесто is not the subject here — it is the object.

The verb расстаивали is in the 3rd person plural past form, but Russian often uses this form with no stated subject to mean someone / people / they in a general sense.

So literally, the structure is closer to:

• They proofed the dough

But in natural English, this is often translated more passively:

• The dough was proofed

Because it is the direct object of расстаивали, so it is in the accusative case.

However, тесто is:

• neuter
• singular
• inanimate

For inanimate neuter nouns, the accusative looks exactly the same as the nominative. So:

• nominative: тесто
• accusative: тесто

That is why the form does not change.

This is a set expression meaning:

• to the point that
• to such an extent that
• even to the extent that

It introduces an extreme result.

So in this sentence, it means that the proofing continued so far that a specific consequence followed: the dough stopped rising.

The comma appears because что introduces a subordinate clause.

The part after it — подъём теста остановился — explains the result or consequence.

So the structure is:

• main part: Тесто расстаивали вплоть до того
• subordinate clause: что подъём теста остановился

In English, the same idea is often expressed with:

• ...to the point that...
• ...so much that...

Literally, подъём теста means the rise of the dough or the lifting/rising of the dough.

• подъём = rise, lifting, increase
• теста = of the dough (genitive case of тесто)

A natural English rendering would be:

• the dough’s rise
• the dough rising

So подъём теста остановился means:

• the dough stopped rising
• literally: the rise of the dough stopped

Остановился is perfective, so it presents the action as a completed result:

• the rise came to a stop
• the rise stopped

That fits this sentence well, because the clause describes the final consequence of the excessive proofing.

If you used останавливался, that would be imperfective, which would suggest something more like:

• was stopping
• used to stop
• stopped repeatedly

That would not fit the meaning here nearly as well.

Because остановиться means to stop or to come to a stop as an intransitive verb.

Compare:

• остановить = to stop something
• остановиться = to stop oneself / to come to a stop / to stop

Here the subject is подъём — the rise itself is what stopped. So Russian uses остановился.

The imperfective past расстаивали emphasizes the process and duration.

It suggests something like:

• they kept proofing it
• they were leaving it to rise
• the proofing went on for some time

This fits the meaning very well, because the sentence describes a prolonged action that eventually led to an extreme result.

Yes, very strongly.

The phrase вплоть до того, что suggests an excessive extent, and подъём теста остановился describes a bad result: the dough was left proofing so long that it was no longer continuing to rise.

So the overall implication is:

• the dough was over-proofed
• they let it proof too long

Because the second теста has a different grammatical role.

• first тесто = the direct object of расстаивали
• second теста = genitive after подъём, meaning of the dough

Russian often repeats a noun like this when each occurrence belongs to a different part of the sentence. It may sound slightly repetitive in English, but in Russian it is normal and clear.

The word order is natural and helps the sentence flow from topic to result.

• Тесто puts the focus immediately on the dough
• расстаивали gives the action
• вплоть до того, что... introduces the consequence

So the sentence moves from:

1. what was being worked on — the dough
2. what was done to it — it was proofed
3. how far that went — so far that it stopped rising

Russian word order is flexible, but this order sounds very natural for presenting a process and then its outcome.