Any reason not to add soy lecithin?

[soontobepcv]

It's in this hot chocolate mix that I have, which is otherwise just sugar, chocolate, vanilla and coffee. Something I read said that there shouldn't be more than 1% by volume, and I'm just using a little in my stout...

 

[Nurmey]

The amount is minuscule and it shouldn't hurt the beer. I only used cocoa in my brews so I'm not sure what the other ingredients will come out like. My concern would be the quality of the mix. Hopefully it's a good mix that uses real ingredients. Let us know how it come out because the combo of choc, vanilla, and coffee in a stout sounds kind of good.