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The Perfumer's Cookbook 4 is one of the many Key Items found throughout Elden Ring, sold by the Hermit Merchant in Ainsel River.
The Perfumer's Cookbook 4 is a Key Item Recipe Book that will unlock extra crafting recipes once you have obtained it.
This includes the following recipes:
This item can be bought by a Hermit Merchant in the Ainsel River under East Liurnia, inside a large chamber under a hanging gravitational beast. It is sold for 3,000 Runes.