Quando lo yogurt è troppo liquido, aggiungo più cereali e meno pera.

Italian normally uses lo before nouns that begin with certain sounds, including many foreign words that start with y. So lo yogurt is the standard form.

You may sometimes hear il yogurt in everyday speech, but lo yogurt is the safer choice for learners.

Italian often leaves out subject pronouns because the verb ending already shows who is doing the action.

• aggiungo = I add
• aggiungi = you add
• aggiunge = he/she adds

So aggiungo already means I add.
You would use io aggiungo only for emphasis or contrast, for example:

• Io aggiungo più cereali, tu no. = I add more cereal, you don’t.

Because the sentence describes a habitual action: what the speaker usually does whenever this situation happens.

• Quando lo yogurt è troppo liquido, aggiungo... = When the yogurt is too runny, I add...

This is a general rule or routine, so Italian uses the present tense in both parts.

È is the verb essere in the third-person singular: is.

The accent is important because it distinguishes è from e:

• è = is
• e = and

So:

• lo yogurt è liquido = the yogurt is liquid/runny
• cereali e pera = cereal and pear

Più means more. It is written with an accent in standard Italian.

In this sentence:

• più cereali = more cereal
• meno pera = less pear

The accent is simply part of the correct spelling of più.

Because liquido is an adjective, and in Italian adjectives usually agree with the noun they describe.

Here the noun is yogurt, which is treated as masculine singular, so the adjective must also be masculine singular:

• lo yogurt è liquido

If the noun were feminine singular, you would use liquida instead.

Here troppo is an adverb modifying the adjective liquido.

• liquido = liquid/runny
• troppo liquido = too liquid / too runny

It means the yogurt is runnier than desired.

Because troppo means too much / excessively, while molto means very.

• molto liquido = very runny
• troppo liquido = too runny

In this sentence, the yogurt is not just runny; it is runny enough to cause the speaker to change something, so troppo is the right choice.

After quantity words like più and meno, Italian often leaves out the article when talking about ingredients or amounts in a general way.

So:

• più cereali = more cereal
• meno pera = less pear

This sounds natural when you are talking about adjusting a mixture, rather than referring to specific individual items.

This is a very natural food-related pattern in Italian.

• cereali is often used as a plural noun meaning breakfast cereal / cereal pieces / flakes
• pera in this context can behave like an ingredient name, meaning pear as a substance or mixed-in fruit

So the sentence sounds like someone is adjusting proportions in yogurt:

• more cereal
• less pear

Yes, but the meaning shifts slightly.

• meno pera = less pear as an ingredient, flavor, puree, or mixed fruit
• meno pere = fewer pears or fewer pieces/units of pear

In a sentence about yogurt ingredients, meno pera sounds very natural because it treats pear as part of the mixture rather than as separate countable pears.