In collaboration with a University of Minnesota sustainable forestry researcher, Urban Growler is using an altogether unusual ingredient in a limited-edition beer.

The ramón nut, which grows in the Guatemalan rain forest, imparts a coffee-chocolate flavor upon roasting — the perfect match for a batch of stout now available at the St. Paul microbrewery. (2325 Endicott St., St. Paul, 651-340-5793, urbangrowlerbrewing.com)

David Wilsey, a researcher at the Humphrey School of Public Affairs, was investigating how the ancient Mayan food source can be a tool of economic empowerment for people living where it grows, when he got the idea to brew the nut into beer. Working with a group of his students, Wilsey secured a grant and approached Urban Growler's owners. Their first batch last spring sold out rapidly. It's back on tap till it runs out.

Wisconsin-based wild ale brewer O'so Brewing is making its Minnesota tap debut Jan. 12. The company brings 5 of its wild, living, barrel-fermented sours to Chatterbox Pub as part of the pub's Into the Woods exploration series all this week. Some of the 18 sours also featured this week include those from Indeed Brewing's Wooden Souls Series and Wild Mind Artisan Ales. (2229 E. 35th St., Mpls., 612-345-4481, chatterboxpub.net)

The days are just beginning to lengthen, but the folks at Finnegans Brew Co. are celebrating the dark. Next week is Dark Week, in which the nonprofit brewery releases a new dark beer every day. (817 5th Av. S., Mpls., finnegans.org)

The festivities begin Sunday with the release of the Smoked Baltic Porter, followed by stouts and porters drawing on the flavors of chocolate, maple syrup, Montana blue spruce tips, mint and bourbon.

Head brewer Ryan Mihm likes to get creative with his beers; he recently brewed a brown stout in a 1,600-pound gourd. Assistant Brewer Logan McLean foraged 9 pounds of blue spruce tips used in the Red Lodge Oatmeal Spruce Tips Porter while on vacation in Montana.

The week culminates with a bottle release party on Jan. 19 at 11:30 a.m. But those who make it every day to try each new beer can earn a free 10-ounce poor of Finnegans' Caorthannach Russian Imperial Stout.

Finally, a whopping 100 Minnesota breweries are converging on Union Depot in St. Paul Jan. 25 at 7 p.m. for Winterfest 2019, a craft beer extravaganza now in its 19th year. More than 30 restaurants and brewpubs are offering small plates to soak up all those suds, some of them with pairings matched to specific beers. Tickets are $90, $50 for designated drivers. (Union Depot, St. Paul, 651-202-2700, mncraftbrew.org)