This article is part of our Best Bars 2015 feature. Find the official 5280 list of the city’s best watering holes, trending cocktail ingredients, essays on the makings of a good bar, drinking alone, and more at 5280.com/bestbars2015.

Chris Sage | Bar manager, Euclid Hall

It’s not so much an ingredient as it is, well, bacteria. Lactobacillus, Pediococcus, and the wild yeast Brettanomyces that all help make sour beers are trendy. The requests for these beers are growing every day.”

John Paul Cook | Bar manager, Dada Art Bar

“Trendy cocktails are really going back to the Mad Men era, which has opened the door for bartenders and patrons experimenting with various types of bitters and herbed liquors. I personally get excited incorporating seasonal ingredients into our cocktails, sourcing as many locally grown and produced ingredients as are available.”

(Read more: The Art of Making Bitters)

Luke “HoneyBear” Ramos | Head bartender, Ste. Ellie

“One of the really exciting things about the craft cocktail boom is how it’s brought back into style more esoteric spirits. Things like quinquina and arrack, both of which are featured in one of my new cocktails at Ellie: Burt Back Arrack. It blends Batavia Arrack, Bonal Gentiane Quina, fresh lime, and honey for what comes out to sort of a funky, wintry daiquiri.”

Kevin Burke | Beverage director, Colt & Gray and Ste. Ellie

“If you spend time on both coasts you see a lot of cocktail bars working with sherry. Williams & Graham pours a fair amount, and it shows up elsewhere from time to time. Colt & Gray or Ste. Ellie has had sherry in a cocktail pretty consistently for the past three to four years. We don’t always list it on the menu because it’s a terrifying ingredient to many. I worry that this is a trend that may skip over the market because it really is one of the most enlightening beverages that you can stumble across. The quality-to-price ratio is really heads and shoulders above anything else in the market. In cocktails, it can provide a dry quality while still enriching texture and with some styles adding levels of savory and umami character.

It seems that potable bitters and amaro are still darling children of Denver bars. What were once seen as confusing and challenging ingredients are now showing up in your neighborhood bars. Campari is back in, thank God; it’s delicious. I feel much more confident ordering a Negroni pretty much anywhere today than I did five years ago in Denver. And thanks to hipsters everywhere, Fernet Branca is available if you need to settle your stomach after over-indulging.

When thinking about the seasonality of cocktails, it’s hard to not want to drink the well-aged stuff this fall and winter. This doesn’t always have to mean whisky, and I think we are seeing more of our guests looking for brandies, both Armagnac and cognac, as well as the great fruit brandies and eau de vie of the world to be used in cocktails. I see more bars with a bottle of Calvados in their speed rail than I have ever in Denver; this makes me happy.

(Video: But if you are looking for that well-aged whiskey drink, try Kevin Burke’s The 4th Pin)

It seems that we haven’t really caught on to the joys of aged rum just yet, which is fine by me. Unfortunately I think there will come a time when the vintage-dated, single-estate rums from Plantation will be as sought after as Pappy Van Winkle is. Until then I’m glad I can pick up a bottle and enjoy one of the most complex spirits that I can find on a backbar at my leisure.”