Homemade Beef Stock

It is nearly impossible to find prepared beef broth that is "safe" (gluten, casein and soy free)...there is most likely caramel color and "natural flavorings" along with maltodextrin in store bought beef broth and these things are all red flags for hidden gluten or casein. Nevermind the use of soybean oil. The only beef broth I've found that looks safe is Kitchen Basics, sold in Central Market,