Το αλεύρι σίκαλης χρειάζεται υψηλή ενυδάτωση.

In Greek, the definite article is very often used with nouns even when you are speaking generically. So Το αλεύρι σίκαλης can mean rye flour in a general sense, not necessarily the specific rye flour in front of you.

This is more natural in Greek than leaving the noun bare. English often says Rye flour needs..., but Greek commonly says Το αλεύρι σίκαλης χρειάζεται....

Αλεύρι is a neuter singular noun meaning flour.

So in the nominative singular, it takes the neuter article το:

• το αλεύρι = flour

Here it is the subject of the sentence, so nominative is exactly what you expect.

Because σίκαλης is the genitive singular form of η σίκαλη.

• η σίκαλη = rye
• της σίκαλης = of rye

So αλεύρι σίκαλης literally means flour of rye, which is how Greek commonly expresses rye flour.

This is a very common Greek pattern:

• χυμός πορτοκαλιού = orange juice
• σούπα λαχανικών = vegetable soup
• αλεύρι σίκαλης = rye flour

No. It is a noun in the genitive, not an adjective.

English often uses one noun to modify another directly, as in rye flour. Greek very often prefers a structure like flour of rye, so it uses the genitive noun:

• αλεύρι σίκαλης

So even though it functions a bit like a modifier in English, grammatically it is still a noun form.

The dictionary form is χρειάζομαι, which means to need.

In the sentence, χρειάζεται is the 3rd person singular present tense:

• χρειάζομαι = I need
• χρειάζεσαι = you need
• χρειάζεται = he/she/it needs

Since the subject is το αλεύρι σίκαλης (rye flour), Greek uses χρειάζεται = needs.

Because the subject is singular:

• Το αλεύρι σίκαλης = rye flour

Even though English speakers may mentally think of flour as a substance or mass, grammatically in Greek it is still a singular noun here. So the verb must also be singular:

• Το αλεύρι σίκαλης χρειάζεται...

If the subject were plural, the verb would also be plural.

Because ενυδάτωση is a feminine noun, and the adjective must agree with it.

• η ενυδάτωση = hydration
• υψηλή ενυδάτωση = high hydration

Greek adjectives agree with the noun in gender, number, and case. So since ενυδάτωση is feminine singular, the adjective is also feminine singular:

• υψηλή

It is the direct object of χρειάζεται, so it is in the accusative.

However, in this phrase, the accusative looks the same as the nominative:

• η υψηλή ενυδάτωση = nominative
• την υψηλή ενυδάτωση = accusative

Without the article, the form υψηλή ενυδάτωση looks the same either way, but its role in the sentence shows that it is the object.

Because Greek does not always use an article with an abstract or general object like this.

Here, υψηλή ενυδάτωση means high hydration in a general sense, so the phrase can appear naturally without an article.

If you added an article, the meaning would become more specific:

• χρειάζεται υψηλή ενυδάτωση = it needs high hydration
• χρειάζεται την υψηλή ενυδάτωση = it needs that specific high hydration

So the article-free version is the natural choice here.

Yes. Greek word order is more flexible than English word order.

The most neutral order here is:

• Το αλεύρι σίκαλης χρειάζεται υψηλή ενυδάτωση.

But you could also move things around for emphasis, for example:

• Υψηλή ενυδάτωση χρειάζεται το αλεύρι σίκαλης.

That puts more emphasis on high hydration.

So the original sentence is the most straightforward, neutral version, but not the only possible one.

A rough English-style pronunciation is:

to a-LEV-ree SEE-ka-lees xree-A-ze-tee ee-psee-LEE e-nee-THA-to-see

A few useful notes:

• χ in χρειάζεται is like the ch in Scottish loch or German Bach
• υψ in υψηλή is pronounced roughly ips
• δ in ενυδάτωση is like the th in this, not the th in thin
• the stressed syllables are:
  • αλεύρι
  • σίκαλης
  • χρειάζεται
  • υψηλή
  • ενυδάτωση

So the rhythm of the sentence matters a lot in sounding natural.