Heart and tongue are muscles and taste enough like beef to be ok in the broth. Let a tongue simmer in the broth and you'll have great tasting broth, plus a couple of extra meals. Heart tastes good on it's own grilled like a steak, imo.

Liver however, will contaminate the flavor of anything within a five mile radius.

I'm not sure how much would be extracted in the broth making process, but I would think that grinding would certianly make it easier to get the good stuff out. I would think just dropping w hole liver in the broth would make it hard to get the good stuff out of the middle.

Of course, if you're going to be grinding your offal anyway, mix it in with some ground beef. You can go up to about 25% before you start to notice it in a burger or on its own, even more if youre putting it in a meat sauce or making taco meat or something where there are a lot of other things going on.

I don't know how much it enhances the nutritional value, but my mom always added the chicken giblets (liver, gizzard, neck) to the pot when she made broth. Typically she'd pan sear the soft organs first then add the neck & chicken carcass. It certainly adds to the flavor.

I actually did a broth this week with ground beef heart meat. Ground it myself with fateful DDR made meat grinder :) I browned the ground meat first to get extra flavor to the broth. This broth went to a braise. There was 1,2L of broth and for that i used 400grams of meat, so you can bet it smelled and tasted intoxicatinly beefy :) I also used one whole beef knuckle bone, it was huge, with all the tendons. Gelling factor was insane :) I pressurecooked the joint 6 hours, all the tendons where rendered to liquid, then i took out the bones, and put new bones, aromatics and meat and pressurecooked 2 hours.

When I make chicken broth, I use the neck, heart and gizzard. I save the liver to eat with eggs for breakfast. I don't notice a difference in the broth but I don't think liver would improve the broth. Heart is kind of like tough steak or stew meat. It could probably be used for broth. I have tried beef heart a few different ways. Here's my recipe: http://formlesssubstance.blogspot.com/2011/02/have-heart-for-valentines-day.html

Tongue is very tender. I wouldn't waste it in a broth. I simmer it for a couple hours, peel the skin off, slice and serve with a sauce.

Chili is a good way to have heart- I dice it up, brown it quickly, then simmer everything for a couple hours.

A couple tablespoons of liverwurst in scrambled eggs is good. I brown the liverwurst first in butter, then add the eggs. Start with just a little, then increase as you get used to it. Good liverwurst has a strong but clean beefy flavor.