oler vs saber a
Oler is smell and saber a is taste — but saber is also 'to know'. The preposition 'a' signals flavour.
oler
To smell — both to give off a smell and to perceive one. Oler a = to smell of.
Huele muy bien.
It smells great.
Irregular: huelo, hueles. Add h before ue.
Huele a humo.
It smells of smoke.
Oler a + noun = to smell like.
¿A qué huele?
What does it smell like?
Question form. Note a qué.
saber a
To taste of — flavour. Not 'probar', which means to try.
Sabe a fresa.
It tastes of strawberry.
Saber a + flavour.
¿A qué sabe esto?
What does this taste like?
Same pattern as oler: a qué.
Este café sabe raro.
This coffee tastes weird.
Saber + adjective for quality of taste.
Tricky bit
'Sé a fresa' would be 'I know of strawberry' — nonsense. For taste use the third person: 'sabe a'. And 'huelo' (I smell) vs 'huele' (it smells) is a different thing from 'sabe' vs 'sé'.