Apenas si alcanzó

Apenas si alcanzó
 

Hi,

Apenas si alcanzó a quitar la olla que empezaba a derramarse en la hornilla.

I suspect this sentence is going to mean more or less the same without si. Does si carry a shade of meaning in this case?

You are right.
The "si" is redundant here. It's colloquial usage, I guess for emphasis, but it's the same as saying "apenas alcanzó a...", meaning that she took the pot away from the stove just in time, before its contents started to drip. :)