Learn Hardcore German: Der Teig ist zu flüssig, um schöne Formen zu halten. - The dough is too liquid to keep nice shapes.

It introduces a non-finite clause that, together with zu + adjective in the main clause, expresses the English idea “too … to ….” Here: zu flüssig + um … zu halten = “too liquid to hold ….” Note that um here is not the preposition “around,” but part of the fixed infinitive pattern.

Why is there a comma before um?

Because German requires a comma before an infinitive clause introduced by um, ohne, statt, außer, als. So the comma in …, um schöne Formen zu halten is mandatory.

Why is it Der Teig and not something else?

Teig is masculine in German, so the nominative singular article is der. With the copula ist, the noun stays in the nominative: Der Teig ist …. The pronoun for der Teig is er.

What case is Formen, and why?

Formen is accusative plural. The verb halten is transitive and takes a direct object: you “hold/keep” something. Here, the thing being held/kept is the shapes.

Why is it schöne Formen (not schönen Formen)?

It’s strong declension because there’s no article before the adjective in the plural. In strong declension, the adjective gets -e in nominative and accusative plural: schöne Formen. (Dative plural would be schönen Formen with an extra -n on the noun: mit schönen Formen.)

Could I say singular Form instead of plural Formen?

Yes, depending on what you mean. Die Form halten/behält nicht die Form focuses on “the shape (in general)”; schöne Formen suggests multiple distinct shapes (e.g., from cookie cutters). Both are idiomatic in the right context.

Why halten and not behalten or bleiben?

die Form halten = “keep/maintain (its) shape” is the standard collocation for substances like dough.
(seine) Form behalten also exists (“retain its shape”), but typically with a possessive: seine Form behalten; saying schöne Formen behalten is less natural.
bleiben is intransitive and used for states like fitness: in Form bleiben = “stay in shape,” not for physical shapes the dough should keep.

Can I drop um and say … zu flüssig, schöne Formen zu halten?

No—after zu + adjective in the “too … to …” meaning, you need um … zu to introduce the infinitive clause. Natural alternatives include:

Der Teig ist so flüssig, dass er keine schönen Formen hält/halten kann.
Der Teig ist zu flüssig für schöne Formen.
More formal: Der Teig ist zu flüssig, als dass er schöne Formen hielte.

Can I add können at the end (ability), e.g., … um schöne Formen halten zu können?

Yes. … um schöne Formen halten zu können is common and emphasizes inability. Without können, halten already implies the idea, but adding können makes the “can’t” explicit.

Where does zu go in infinitives, especially with separable verbs or modals?

With a simple verb: … zu halten.
With a separable verb: … aufzuwärmen, … auszustechen (the zu sits between prefix and stem).
With a modal present: … halten zu können (the zu stands before the final verb in the cluster, here the modal).

Does um … zu require the same subject as the main clause?

Yes: the understood subject of the um … zu clause is normally the same as the main-clause subject. Here, the dough is (not) the one “holding” shapes. If you need a different subject, use a dass clause or the als dass construction, e.g., …, dass die Plätzchen nicht ihre Form behalten.

What’s the difference between zu flüssig, sehr flüssig, and so flüssig?

zu flüssig = “too liquid” (exceeds an acceptable degree).
sehr flüssig = “very liquid” (high degree, no judgment of sufficiency).
so flüssig is typically paired with a result clause: so flüssig, dass ….

Could I use für instead of um … zu?

Yes, as a concise alternative: Der Teig ist zu flüssig für schöne Formen. It’s a bit more compact and neutral; the um … zu version ties the degree directly to an (in)ability.

Is the plural Formen correct for the noun Form?

Yes. die Form (feminine), plural die Formen. In the sentence, it’s accusative plural: schöne Formen.

Any spelling pitfalls in flüssig?

Use ss, not ß: flüssig. After a short vowel, German uses ss (compare muss, Flüsse). ß follows long vowels or diphthongs (e.g., groß).