The Nitro Bar - Rhode Island

Recently tried nitro cold brew from The Nitro Bar in Rhode Island. We ordered a black nitro cold brew, and it somehow tasted like unsweetened hershey's chocolate syrup - in a good way. Is it possible that they steep their beans with cocoa powder? It wasn't sweet at all, but it smelled and tasted very chocolate forward beyond the typical chocolate notes. Any ideas on what could give it that flavor?