Some recipes for applesauce do not call for lemon juice. However, I always add lemon juice when I’m canning applesauce for two very important reasons - one more important than the other. The first reason is that it helps to preserve the natural colors of the apples. It will prevent your jars of applesauce from turning an unpleasant brown color. The other reason has to do with food safety. Usually, you won’t need to add any more acidity to your applesauce because the tartness of the fruit will take care of that for you - and render your applesauce safe for canning in a water bath canner. However, some varieties of apples and various harvesting conditions can lead to apples that are of significantly lower acidity. Normally, you’ll be fine - but adding a dash of lemon juice to each jar will ensure that your jars stay safe in storage for much longer.