I have lvl56 Herblore right now. I know the Ale gives you +1herblore temporarily and I'm needing lvl57 for the quest. Will this concept let me do the quest?

Yes, other methods like evil stews also work. Just be sure to drink it only when you need to otherwise you need multiple drinks.

Buy 2 greenmans in the event you mess up. You will only need level 57 herblore when making the magic essence potion.

One tip I saw somewhere for drinks usage:

 

 

 

 

 

 

 

Fight something low, but must get hit for a little damage.

 

 

 

Watch the stats until you recover a hitpoint, THEN drink, ensuring that you have just passed a clock tick - if you had drunk the moment before that tick, a +1 boost would wear off immediately.