Why deglaze with wine or add vodka to tomato sauce? Breaking down the science of cooking with alcohol

Vodka barely tastes of anything on its own, but that’s exactly why it works here—its job isn’t to add flavour; it’s to draw more of it out of everything already in the pot. J. Kenji López-Alt, the chef and food journalist behind The Food Lab—a column on the Serious Eats blog and later, a book of the same name—ran repeated tests on vodka sauce and found that the alcohol amplifies the tomatoes’ fruity aroma while also lending a background heat and sharpness (ethanol irritates in a way similar to capsaicin, albeit much milder) that cuts through the richness of the cream. His tested method: a quarter cup of vodka for every quart of sauce, simmered for about seven minutes—long enough for the alcohol’s rawer edge to burn off without losing what it pulled out of the sauce.

Tatler Trivia: Curious to learn more about vodka sauce and its contested origins? Check out the 2022 documentary Disco Sauce: The True Story of Penne Alla Vodka.

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Flambéing is a cooking technique where alcohol is added to a dish and ignited, creating a brief flame that burns off much of the alcohol while enhancing the dish’s flavour and aroma.

Bananas Foster, cherries jubilee and steak Diane all put alcohol to real use, though the flame does less of the actual work than it looks like. In each case, the caramelisation or reduction is already underway in the pan before the spirit goes in; igniting it adds a burst of extra heat, burns off some of the alcohol’s harsher edge and contributes the aroma and drama that make these dishes memorable. Since you’re setting it ablaze, you’re looking for something with about 40 per cent alcohol by volume or higher.

There are exceptions to the rule. Baked Alaska is flambéed largely for spectacle: the meringue is already browned, in the oven or with a blowtorch, before the rum ever goes on, so the flame has little left to do beyond a moment of surface heat. Crêpes Suzette sits in between—the crêpe itself is fully made before the liqueur is added, so there’s not much cooking chemistry happening either, but the orange liqueur still earns its place by contributing real flavour to the sauce, echoing the citrus already in it.

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Most of the beer in a beer batter doesn’t survive the fryer, so this is another application that is less about flavour and more about texture—and beer is actually doing four separate jobs.

Beer adds lightness: when the cold, carbonated batter hits the hot oil, the carbon dioxide rapidly expands into bubbles, creating a lacy, airy crust. That explosion of gas also insulates the fish, at least to some degree, preventing a dry, overcooked centre.

Why not just use club soda? While this is a common substitute, the alcohol in beer makes a difference, too. Ethanol evaporates faster than water, which means that you’ll need less time in the fryer to achieve the same level of crispness. Finally, ethanol doesn’t hydrate flour the same way water does, particularly its protein, preventing the excessive gluten formation that can result in a chewy, doughy coat.

The same logic applies to tempura batter, where chefs sometimes employ vodka or sake (though this is not traditional by any means). Some may even add cold, sparkling water to reap the benefits of carbonation too. It’s also worth noting that temperature alone affects the final result. Ice-cold water, even without carbonation, also fights gluten, as cold temperatures discourage gluten formation. The cold batter also produces its own kind of bubbling: the sudden shift from cold batter to hot oil results in bursts of steam, puffing the crust in the same way carbon dioxide does.

See also: Types of water explained: seltzer, club soda, mineral water and more

Rarely completely. A 1992 study in the Journal of the American Dietetic Association (Augustin et al.) tested six alcohol-containing recipes and found retention ranging from 4 to 85 per cent, depending on method. In their tests, a dish simmered for 15 minutes still held around 40 per cent; at one hour, about 25 per cent; at two-and-a-half hours, around 5 per cent. Even their flambéed sample retained roughly three-quarters of its alcohol. The takeaway isn’t a fixed number; it’s that “the alcohol burns off” is a rule of thumb, not a guarantee, and real retention varies by technique far more than any single figure suggests.

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