As the days grow darker and the nights colder, winter is the time of year to huddle close in a pub with a warming drink. But, instead of a mulled wine or a hot toddy, in Brussels people celebrated the end of one year and the coming of the next with a “Kalibabou” – a hot cocktail of lambic, rum, sugar and eggs.

The Kalibabou - not for weak stomachs

The Kalibabou was popular in the cabarets and estaminets of Brussels, when “there was a tradition of offering your clients a warm lambic as a New Year’s gift. Into this was mixed rum and beaten eggs. This drink was not always appropriate for people with a weak stomach.” Aside from this spare description, the drink is a bit enigmatic. Its popularity must have declined just as that of straight, unblended lambic did in the early 20th century. I could find no information about how the drink was made, how popular it really was, and what it actually tasted of. Even the origin of the name, with its echoes of Belgium’s colonial history in central Africa, is a mystery.

There is no recipe that I could find, and although Brouwerij Boon produced a once-off “Kali Babou” for the 2012 Zythos beer festival, they do not mention eggs or heating. There are, however, plenty of analogous pre-20th century drinks that are made up of some combination of beer, rum, and eggs. The “Hot Ale Flip” is one of them.

Taking inspiration from the "Flip"

The flip was a mixed drink, popular in colonial America and still drunk in the 19th century. Hot Ale Flips were made by mixing beer, rum, and sugar (eggs were later added), heated by thrusting a red-hot poker into this mixture. The heat from the poker would warm the drink, caramelize the sugar and cause frothing, or “flipping”. In some places, the froth was made frothier by repeatedly decanting the flip from one jug to another. Sometimes other ingredients would be added to give a seasonal or festive spin – lemon peel, cinnamon, nutmeg, and even dried pumpkin.

Lambic – spontaneously fermented with wild yeast – was the predominant type of beer that people drank in this part of Belgium, so it is not too much of a stretch to imagine a hot, spiced beer drink that substitutes lambic in for any other type of beer that may have been used elsewhere. Just take this scene from revolutionary America: “At tables on both sides of the fire, men played cards, puffed on clay pipes and swigged from mugs filled with warm, frothy flip…and talk of war flowed as freely as the flip poured from ceramic pitchers”. It could just as easily be transplanted to Brussels, ceramic lambic jugs and all.

Lambic from the Payottenland

I decide not to let this gross anachronism get in my way of reviving the Kalibabou, and so I gather together the ingredients. For guidance, I am leaning heavily on this Hot Ale Flip recipe from Punch. Rum, eggs and sugar we have. Absent a hot poker, a gas hob will suffice. Sourcing unblended lambic is a little more complicated because Brasserie Cantillon, Brussels’ only lambic producer, does not sell it. Instead, early one bitterly cold Saturday, I get on my bike and cycle out to the Oud Beersel brewery in Flemish Payottenland. There, at the brewery’s shop, I can buy a five-litre bag-in-the-box container of Oud Beersel Lambiek, which is brewed at Boon and barrelled at Oud Beersel.

It looks hazy, the lambic, and certainly less opaque than I had expected. There is little carbonation, save for a thin bead at the rim of the glass. It gives of an aroma of green apple sweetness, with a hint of sulphur. A little barnyard funkiness comes through, but not is not overpowering. Tasting it, there is sweetness there too, but also a big mouthful of tannic, acidic bite that sticks to the gums. It reminds me of a dry cider, with a sharp, funky finish and lingering bitter-sour aftertaste.

The lambic goes into a saucepan and onto the hob, to be warmed but not boiled. Into a jug goes the rum, an egg, and sugar syrup, whisked together to make a “batter”. Once the lambic is steaming I take it off the heat and combine, slowly and still whisking the batter, the two mixtures. I do not want scrambled eggs in a glass. To froth it up I decant the Kalibabou mixture from one jug to another, back and forth for a minute or two.

Looking like a latter-day New England IPA

Satisfied with my froth, I pour the mixture into a glass and dust it with nutmeg. This Kalibabou is thick and murky, a deep, dull orange; it looks for all the world like a latter-day New England IPA. As for the aroma, the earthiness of the nutmeg overpowers everything else.

I take a gulp, and think of my weak stomach.

The sweet-sour lambic is still there at the beginning, followed by a warm rummy punch that gives me the shivers. The tannic stickiness of the lambic is still there too, thought it is smoothed-out by the egg. The after taste is, however, all lambic sharpness and tang. Bascially, there is a lot of lambic still present.

I make myself another one. This time I let the lambic come just to a boil, and I beat the batter a little harder to work up more foam. Out goes nutmeg and in comes cinnamon, which turns out to be less overpowering and gives it a more seasonal kick. The results of my more vigorous frothing are negligible.

Two is enough

Two of these Kalibabous is enough. My stomach may have passed the test, but the egg makes them heavy going, and I can feel the rum getting to work on me. Like most Christmas or winter drinks, eventually it becomes a little too sweet and cloying. But this Kalibabou does have a proper boozy, sweet, Christmas cocktail vibe.

It may not be the most historically accurate interpretation of the New Year’s treat that was swilled in the cabarets and estaminets of Brussels. I don't expect to see being served in the stalls of Brussels' Christmas market next year, but I would drink it if they did. Then again, with four litres of lambic still loitering in the fridge, I would say that. 

A contemporary Kalibabou

• 50ml rum

• Sugar syrup (50g brown sugar, 50ml water)

• 250ml Oud Beersel Lambiek

• Cinnamon stick, grated

• Eggs, to taste

To go full Christmas, pair with pepernoten, the spiced biscuits that are ubiquitous in Belgium and The Netherlands during winter.