The Partitive Genitive (-у/-ю)
When expressing a specific quantity or a portion of an uncountable noun (like liquids, foods, and materials), Russian uses the genitive case.
However, a special group of masculine mass nouns has an alternative "second genitive" (or partitive) ending: -у or -ю. You can think of this ending as carrying the meaning of "some" of that item.
For example, чай (tea) becomes чаю, and квас (kvass) becomes квасу. You will often see these forms paired with measure words like чашка (cup) or глоток (sip).
| I want to pour you a cup of tea. | Я хочу налить вам чашку чаю. |
| Give me a sip of kvass, please. | Дайте мне, пожалуйста, глоток квасу. |
Groceries and Ingredients
This pattern isn't just for drinks. It also applies to solid uncountable foods like сыр (cheese), чеснок (garlic), and перец (pepper).
To talk about specific amounts, you can use portion words like кусок (piece), кусочек (small piece), or щепотка (pinch).
| In the cafeteria, I bought a large piece of cheese. | В столовой я купил большой кусок сыру. |
| You need to add a pinch of pepper and a little garlic to the soup. | Надо добавить в суп щепотку перцу и немного чесноку. |
Asking, Pouring, and Adding
You will frequently hear the partitive genitive when someone is asking for something, adding ingredients, or using verbs like налить (to pour). It appears with everyday staples like мёд (honey), сахар (sugar), суп (soup), and коньяк (cognac).
Note: Using the standard genitive for these words (such as *чашка чая or кусок сыра) is completely grammatically correct and very common today. The -у / -ю forms simply add a natural, slightly traditional flavor when talking about portions.*
| Waiter, can you pour me a shot glass of cognac? | Официант, можете налить мне рюмку коньяку? |
| Can you bring a small piece of sugar or a spoonful of honey? | Вы можете принести кусочек сахару или ложку мёду? |
| Grandmother poured me some soup. | Бабушка налила мне супу. |