asg zone,

Lemon juice is a little bit more acidic than vinegar, so if you are canning with BWB you would not want to make this substitution, I would think, in something like a salsa with significant amounts of low-acid vegetables where the amounts would have been carefully calibrated to make sure the pH was at a safe level.

But where you're talking about mostly apples and sugar (I assume the ginger amount is in spoonfuls and not cupfuls!), I can't see how it would be problematic. You could can apples, brown sugar, and an amount of ginger likely to be used for for flavouring without adding any acid at all. The lemon juice is probably there mostly to prevent browning, which vinegar would do, and maybe to bring out the apple flavour a bit more, which it might as well.

Zabby

Is is possible to substitute vinegar for lemon juice safely?

I agree with Zabby. In some recipes it would be ok as in the one you describe. Vinegar would change the taste significantly so I would be inclined to leave it out and be content with some browning of the apples instead.

But it would depend on the recipe. You can't say yes, it's ok as a general rule of thumb. In many recipes it wouldn't be a safe substitution.

Dave

You might like to investigate verjuice if you can't use citrus. It could be used in many of the ways you'd use lemon juice. For providing a zing with fish sorrel is handy and a cinch to grow. And if you decide on vinegar there are lots of varieties some milder than others. I've used a little cider vinegar in apple sauce before now and I should think that would be ok in your apple ginger recipe. (I'm assuming that uses fresh ginger so it would already have a pretty strong taste.)

Great, thank you for the responses. My thought was also that with apples and sugar it should be ok but I didn't feel quite confident enough to go ahead and do it. I definitely would use cider vinegar. Perhaps I'll try one batch with vinegar and one without and see how they compare.

I'm not familiar with verjuice, I'll have to go look it up. Thanks again.

Bottled lemon juice is twice as acidic as vinegar. It is not safe to sub vinegar for lemon juice in most cases.
It would depend upon how much ginger, is is fresh, etc. as to whether the lemon juice is for safety or just for flavor.

It would really be better to see the recipe and the proportions before making any recommendations.

As Linda Lou said, it depends on the amount of ginger and perhaps other ingredients as well.

Carol

You also have the choice of usin apple cider vinegar. There are also tarteric and malic acid that can be used. These are measure nearly the same amount compared to citric acid, but are from fruits/berries other than citrus.

Sorry - I lost sight of the OP's first question re canning. I should have made it clear my ideas were not recommendations for preserving, only for possible substitution candidates in cooking to eat straight away or freeze. I was thinking in terms af flavour rather than preserving characteristics.

With respect to eating right away or freezing, don't know if you would be allergic to citric acid but if not, as Ken said above, that could be used in cooking for immediate consumption for a "bite" in food similar to citrus flavor (only for the bite - however). Citric acid will NOT taste like the lime or orange flavors that many of us savor. I would however, if allergic to citrus, start looking into the other fruit acids for that "gummy bear" bite that bottled lemon juice will often give. I have it in mind that 1/2 tsp. of citric acid is equivalent to 2 Tablespoons of lemon or lime juice as a place to start in recipe substitution (hope my recollection is correct). Remember, adjusting the particular ratio will be up to your particular taste. We can't help you there.
Just another voice offering help (God would I hate to be allergic to citrus)
Jim in So. Calif.

Malic and tarteric acid are good alternates for that sourness. They can be found at wine making supply stores.