Fair warning: You could brew a “marshmallow” beer and not have to deal with real marshmallow at all.
For one thing, you might get marshmallow-like character via vanilla, residual sweetness, and big, fluffy body. For another thing, you could use marshmallow-flavored extracts. I reached out to about a dozen different breweries to ask about marshmallow beers, and the low response rate was atypical. Matt Arens of Amundsen Bryggeri in Oslo, Norway, did respond, and he’s straightforward about how they do their “marshmallow-inspired” beers, such as Marshmallow Psycho imperial stout and Chocolate Marshmallow Dessert in a Can.
“It’s worth noting to you up front, that in each of these beers, we don’t work with actual marshmallows,” Arens says. “Processing them in the brewhouse and/or cellar just proves a huge mess and somehow still lacking in full-on marshmallow intensity. We’ve sometimes framed some of our beers as ‘marshmallow beers’ but have instead just loaded them up with Madagascar vanilla beans, which lend a marshmallowiness to the beer when added in large volumes.
“In other instances, we’ve used a natural marshmallow flavoring in extract form,” Arens says. “It might not be as romantic as adding marshmallows to the whirlpool or fermentation vessel, but we’ve been happy with this method for our beers.”
I’m going to refrain from judging any brewers using flavor extracts when I have yet to clean out a pile of sticky marshmallow goo myself. But we’re no closer to knowing how to work with the real thing.
Yet there are brewers out there putting actual marshmallow into their kettles and fermentors.
At Perennial Artisan Ales in St. Louis, for example, brewer Chris Kinast says they use marshmallow fluff. For their recent Lunchbox Treasures imperial stout, they added 4 lb (1.8 kg) of fluff per barrel at the end of the boil, finishing the beer on 6 lb (2.7 kg) of fluff per barrel. If we convert that to five-gallon/19-liter homebrew-size, that’s roughly 10 oz (283 grams) of fluff at flameout, and 1 lb (454 grams) in the fermentor.
Kinast says it was not as bad of a mess as he expected, and he’s thinking of increasing the marshmallow amounts and steeping time when they brew it again. “I would guess a lot of breweries in general are loading up these stouts with extracts,” he says. “Marshmallow is hard to convey because it just comes off as sweetness. We really dialed back the vanilla to not distract from the different flavor profile of the ’mallow.”
Another brewery devoted to real ’mallow is White Elm in Lincoln, Nebraska. Kolby Wood, cofounder and head brewer, says they add about 200 lb (91 kg) of whole marshmallows to a 15-barrel batch of Fluffaluffagus imperial stout. That works out to about 2.2 lb (1 kg) for a five-gallon batch. One-fourth of that goes into the kettle, and the rest is post-fermentation. (They also brew a version with peanut butter, called Fluffernuttergus.)
Wood warns against putting too much marshmallow into the kettle. Marshmallows will melt and dissolve into the solution—but on the way out, going through the chiller, the cornstarch from the marshmallows gelatinizes as it cools, so it sticks. “We learned the hard way about that,” he says.
White Elm uses large marshmallows they buy in bulk—similar to the Jet-Puffed brand you see in the supermarket—but Wood says that homebrewers might prefer the mini-size for easier dissolving. Another suggestion, which White Elm has used in a couple of “smoothie sours,” is marshmallow coconut toasties—i.e., marshmallow squares covered in toasted coconut, which anyone can buy from Nuts.com.
Wood says that marshmallow brings a vanilla-like flavor that really “pops.” However, he’s blunt about what it’s like to clean up afterward: “It’s a terrible mess,” he says. “It’s nightmarish cleaning that tank.”