Without beer in a savoury recipe or batter, the closest result comes from sparkling water with a splash of vinegar or an apple juice and sparkling water mix; both mimic some of beer's mild tang and its lift from carbonation.
What does beer actually do in a recipe?
Beer plays two roles, especially in frying batters and certain braises: its bubbles lighten the batter, while the mild tang from fermentation adds depth to a dish. In beer-battered recipes, that carbonation is what keeps the fried coating crisp and light; with plain water the result comes out heavier and less puffed up.
In stews and braises, beer also helps soften the meat's fibres and leaves a faint caramelised note as it cooks down.
Which alternative works where?
For batter, sparkling water with a little vinegar gets closest to beer's carbonated lightness; the fizz from the water lifts the batter while the vinegar adds a mild tang. An apple juice and sparkling water mix is both sweet and fizzy, so it suits recipes where a touch of sweetness isn't a problem.
For stews and braises, a little vinegar-spiked stock or ayran can help tenderise the meat in a similar way, though none of these alternatives fully reproduces beer's own fermented aroma.
What should you watch out for?
If you want the lift, mix the alternative in right before frying — carbonated mixtures lose their fizz over time and their lifting power drops with it. If you use a sweeter alternative, cut back a little on the sugar elsewhere in the recipe, or the result can end up too sweet.
Keep vinegar-based alternatives in check too; too much vinegar can leave an unwanted sharpness, so it's safest to add it gradually and taste as you go. Keep the batter's overall liquid volume the same as with beer — only the source of the liquid changes.
How do you use a beer substitute in sweet recipes?
In some breads and cakes, beer serves as both a leavening agent and a source of mild malty flavour; for these recipes, the apple juice and sparkling water mix is the better fit for both sweetness and carbonation. If you want that malty note, a few drops of molasses stirred into the mix can partly make up for it.
Whatever the recipe, mix the substitute together right before you need it — carbonated mixtures left standing lose their fizz, and the lift they give drops off noticeably.
If you're trying a beer substitute for the first time, setting aside a small portion to test first lets you see how the flavour turns out without risking the whole batch.
Non-alcoholic beer is also available in some shops; it won't add lift to a batter, but its flavour is one of the closest matches to real beer, so sparkling water should still be added for the rise.