Malt vinegar lends a rich, nuanced flavor to recipes. It's made by brewing malted barley in a process similar to beer brewing. Like wine vinegar, malt vinegar is strong, flavorful, and improves with age. If a recipe calls for malt vinegar but you don't have any or you have a sensitivity to barley, you can sub in other types of vinegar and condiments.
Wine or Cider Vinegar
To substitute for malt vinegar in marinades, use a strong grape or red wine vinegar that's been aged. For those who can't consume malt vinegar due to dietary sensitivities, an aged, high-quality apple cider vinegar is an excellent gluten-free alternative. The flavor notes won't be exactly the same, but the impact will be similar.
Balsamic Vinegar
Malt vinegar is a popular dipping sauce for the British dish of fish and chips as well as French fries in other parts of the world such as Canada. A quality balsamic vinegar is a great substitute in these scenarios. Blend it with olive oil and other spices for a dynamic vinaigrette.
Other Substitutes
Because it's also tart, lemon juice can pass for malt vinegar in baked dishes. You can try a blend of lemon and lime extract as well.