Learn Hardcore Finnish: Ostan shampoota, koska se loppui kesken.

Finnish uses the partitive to express an indefinite or unbounded amount, especially with mass nouns. Shampoota means “some shampoo.” You’re not committing to a fully specified, countable item; you’re just buying an unspecified amount/product.

Typical with mass nouns: ostan maitoa, ostan kahvia, ostan shampoota.
If you make it a specific, bounded item (a particular product/bottle), you can use the total object: Ostan shampoon (see next Q).

What’s the difference between Ostan shampoota and Ostan shampoon?

Ostan shampoota: indefinite mass/unspecified amount (“I’ll buy some shampoo.”).
Ostan shampoon: total/specific object (“I’ll buy the shampoo” or “that shampoo we talked about,” often implying a particular bottle/brand). Both are correct; the choice signals whether the object is an unspecified substance vs. a specific, bounded purchase.

Why is it spelled shampoota and not shampooa in the partitive?

Loanwords ending in long vowels typically form the partitive with -ta/-tä, preserving the long vowel:

shampoo → shampoota Compare: video → videota, tee → teetä. Writing shampooa is a common learner error.

Why is the main clause in the present (Ostan) but the reason clause in the past (loppui)?

Finnish present covers both English present and near future, so Ostan naturally means “I’m going to buy.” The reason describes a completed past event, so loppui (“ran out”) is in the simple past. This tense sequence is normal: present intention caused by a past event.

What exactly does loppui kesken mean? How is it different from just loppui?

loppui = “ran out/ended.”
loppui kesken adds the nuance “ran out before I finished” / “ran out on me, mid-way.” It’s a common idiom emphasizing untimely insufficiency. Both are fine here; kesken adds the “prematurely/in the middle of things” flavor.

Could I say Ostan shampoota, koska se on loppu instead?

Yes. Se on loppu means “it is (all) out.” It describes the current state rather than the past event. Subtle nuances:

koska se loppui (kesken) = focuses on the event that happened (it ran out).
koska se on loppu = focuses on the present result/state (it’s out).

What does se refer to here? Can se refer back to an indefinite mass like shampoota?

Yes. Se refers to the shampoo as a discourse referent (the substance/product), even if introduced in the partitive as an indefinite mass. Finnish pronouns are not tied to English-style definiteness rules; once introduced, the referent can be picked up with se. You could also say: Shampoo loppui (kesken).

Could I drop se and just say … koska loppui kesken?

No. Finnish generally requires an explicit subject in such clauses. Keep se or name the subject:

… koska se loppui kesken.
… koska shampoo loppui kesken. Another common pattern with a possessor: … koska minulta/mulla loppui shampoo (kesken).

Why is there a comma before koska?

In standard Finnish, a comma precedes a subordinate clause introduced by koska, regardless of clause order:

Ostan shampoota, koska se loppui kesken.
Koska se loppui kesken, ostan shampoota.

Can I use kun or sillä instead of koska?

kun can mean “when,” and colloquially it can imply a causal “as/because,” but koska is the clearest, neutral causal conjunction.
sillä is a coordinating conjunction meaning “for,” more formal/literary, and it doesn’t create a subordinate clause. It would typically start a new clause: Ostan shampoota, sillä se loppui kesken.

What’s the difference between loppua and lopettaa?

loppua is intransitive: something ends/runs out by itself. Here: se loppui (kesken) = “it ran out.”
lopettaa is transitive: someone stops/ends something. E.g., Lopetin pesemisen = “I stopped washing.” Don’t use lopettaa for supplies running out.

Is Minä required in Ostan?

No. The person is marked on the verb, so Ostan already means “I buy/I’m going to buy.” Adding Minä is possible for emphasis or contrast: Minä ostan (as opposed to someone else).

How would I say “I ran out of shampoo” as a standalone sentence?

Several natural options:

Shampoo loppui. (neutral)
Shampoo loppui kesken. (ran out mid-way; more emotive)
With a possessor: Minulta/mulla loppui shampoo (kesken).
State/result: Shampoo on loppu. (“The shampoo is out.”)

How do the other tenses of loppua work here?

Present: se loppuu = “it runs out / it’s running out.”
Past (simple): se loppui = “it ran out.”
Perfect: se on loppunut = “it has run out.” Choose based on whether you describe an ongoing process, a completed past event, or the present result.