Без дуршлага трудно быстро промыть рис после варки.

Because без always takes the genitive case in Russian.

• Dictionary form: дуршлаг = colander
• After без: без дуршлага = without a colander

This is a very common pattern:

• без воды = without water
• без сахара = without sugar
• без машины = without a car

So the ending -а here is not random; it shows the genitive singular of a masculine noun.

Russian often uses impersonal sentences when talking about what is generally easy, hard, possible, necessary, and so on.

So:

• Без дуршлага трудно быстро промыть рис после варки.

literally works like:

• Without a colander, [it is] difficult to rinse the rice quickly after cooking.

There is no need to say это or вам / мне / человеку unless you want to specify who finds it difficult.

This is very natural in Russian.

Трудно is an adverb / predicative word meaning difficult in an impersonal construction.

Compare:

• трудный = difficult, hard
  Used as an adjective before a noun:

  • трудная задача = a difficult task

• трудно = it is difficult / difficultly
  Used in sentences like:

  • Трудно понять. = It is hard to understand.
  • Мне трудно говорить. = It is hard for me to speak.

In your sentence, Russian needs the impersonal form:

• трудно промыть = it is difficult to rinse

not the adjective трудный.

Промыть means to rinse / wash through, often with the idea of washing something thoroughly or by running water through it.

For rice, промыть рис is very natural, because you are usually rinsing it.

A quick comparison:

• мыть = to wash
• помыть = to wash something
• промыть = to rinse / wash through thoroughly

Also, промыть is perfective, which fits well here because the sentence refers to completing a single action:

• трудно быстро промыть рис = it is hard to rinse the rice quickly

If you used промывать, that would sound more like a repeated or ongoing process.

Because рис is a masculine inanimate noun, and here it is the direct object of промыть, so it is in the accusative case.

For masculine inanimate nouns, the accusative is usually the same as the nominative:

• рис → рис

Compare:

• Я вижу стол. = I see a table.
• Я промыл рис. = I rinsed the rice.

But with animate masculine nouns, accusative would often match the genitive instead.

Варка is a noun meaning boiling / cooking.
It comes from the verb варить = to boil / cook.

After после (after), Russian uses the genitive case, so:

• варка → варки
• после варки = after cooking / after the cooking process

This is a compact, natural Russian way to express the idea.

You could think of it as similar to English after cooking rather than after you cook it.

Yes. Russian often has two options:

1. A noun phrase:

   • после варки = after cooking

2. A full clause:

   • после того, как рис сварился = after the rice cooked / after the rice was cooked

The version in your sentence is shorter and more neutral. It sounds like a general practical statement, which fits well here.

In Russian, word order is flexible, and быстро here modifies the action промыть.

So:

• трудно быстро промыть рис

means:

• it is hard to rinse the rice quickly

The position is natural because быстро is closely tied to the infinitive.

Other word orders are possible, but they may shift emphasis a little:

• Без дуршлага трудно промыть рис быстро.
• Без дуршлага рис трудно быстро промыть.

All are understandable, but the original sounds smooth and neutral.

Not exactly.

• варка specifically relates to boiling / cooking by boiling
• готовка means cooking in a broader, more general sense

Since rice is commonly boiled, после варки is very appropriate.

If you said после готовки, it would sound broader and a little less precise.

It can be broken down like this:

• Без дуршлага = without a colander
• трудно = it is difficult
• быстро промыть = to rinse quickly
• рис = rice
• после варки = after cooking

So the pattern is basically:

• [Without X] + [it is difficult] + [to do something] + [object] + [time phrase]

This is a very useful Russian structure. For example:

• Без словаря трудно читать. = Without a dictionary, it is hard to read.
• Без очков трудно работать. = Without glasses, it is hard to work.

As a general practical statement, something like:

• Without a colander, it’s hard to rinse rice quickly after cooking.

It does not sound literary or unusual. It sounds like ordinary, everyday Russian, especially in a cooking or household context.

The sentence is general, not about one specific person. It expresses common experience rather than a personal complaint.