They seem to be made very similarly.
They both can be made from bones, veg etc. I know technically au jus refers to using the juices of the meet that you're cooking but i've seen people make a "jus" with bones and offcuts... which sounds exactly like what you do for a stock.
Is it because people add things like wine to a jus where a stock is usually just meat, bones and veg?
What's the difference?
Jus generally refers to a sauce or accompaniment, served alongside or on top of some other food.
Stock is a (generally gelatin-rich) broth used during the cooking process, whether as a braising/cooking liquid, or reduced/thickened into another sauce.
There are varying ways to make both; the terminology mainly refers to how they're served or used. In my opinion, "jus" is just a fancified way to refer to a stock served as a final component of a meal rather than an ingredient during cooking.
A jus is a sauce made from pan drippings, typically beef fat, with added stock, and perhaps thickened with cornstarch or flour. A stock is a liquid produced by simmering raw ingredients (veg and meat bones), which then becomes the base for soups and sauces (like a jus, for example).
In French cuisine, stock is referred to as fond, and it is preferable to use that term. It is generally made of bones and flavored with root vegetables and herbs. It is either brown from roasting these or not, and then is white – fond blanc. This is later refined to a jus by deglazing a frying pan with (usually in butter fryied and strained from excess fat, a mix of fresh, new vegetables, meat trimmings, new herbs, and spices) with strained fond (stock). It is reduced to a sirupy consistency and finished with fortified wines and butter, or cognac. It's not the same as demi-glace because they both have a partial reduction, but demi-glace is the ingredient (reduced fond), and jus is the finished product. Fond is an extraction medium for the jus in this case. You can extract a small amount of this when you roast premium cuts in an oven with vegetables and flavourings. The jelly from well roasted chicken on the bottom of the tray is jus. But it is generally not enough and is generally too salty – so gravy is generally made of it. It is thinned with water or stock and thickened with flour or starch. Jus is the extracted juice of the meat in the simplest possible explanation for this Q, but it can get complicated.
