Warbands warbands warbands
If you want the best Essence then you need local silver currency from one fishing daily and the local warbands to buy the essence recipes. To increase your chances you need a Westernmet Journal bought with Rohan Iron coins, again after questing is done it's Rohan warbands for the currency.
Is there another way to get the journal recipes than to go back to Rohan to kill warbands for the iron coins?
Not to mention the Emerald Shard grind.