Can lime juice and lemon juice be used interchangeably in recipes?
The taste will be slightly different, of course, but beyond that, there shouldn’t be any reason why you can’t make the swap. Lime is a bit more floral, but if the lemon juice is acting as a thickener, such as in a lemon curd or lemon pie, the lime juice should still have enough acidity to do the job. One instance in which you cannot swap is when you are canning tomatoes in a boiling-water canner. Recipes for canning tomatoes call for commercial, not fresh, lemon juice because the percentage of acidity in fresh fruit can vary widely, from 2.5 percent to 4.5 percent. (It depends on how old the fruit is, the season when it was picked and even how rainy it was.) You need a dependable level of acidity to make tomatoes safe for canning, so you should always use bottled lemon juice if the recipe calls for it. And you certainly shouldn’t swap in lime juice. One other tip I turned up, at www.baking911.com, is that you shouldn’t swap grapefruit juice for lemon juice in baking because it is lower
