I’ve heard conflicting opinions on this.
Should I brown my meatballs before I put them in the tomato sauce. yea or nay?
Why or why not?
ETA - they will cook at least another hour or two in the tomato sauce.
And don’t try to talk me out of browning the sausage, darnyouall!
My mom always did. I consider that definitive.
Yes. Browning the meat gives it a different flavor and texture. I brown roasts and stew meat before oven cooking or crocking them.
Anyone know why someone would advise me not to brown them? I’ve head it from multiple sources without explanation.
I’ve always browned them in the past.
My Dad, who taught me the basics, does not brown. The student has since surpassed the master, and I brown. It adds flavor, but dirties another pot or pan. As long as you braise them long enough, a goods meatball will be fine either way.
In addition to adding flavor, the caramelization tends to help hold them together whilst simmering. I can’t imagine NOT doing it.
There are two factors that I can think of that would influence the decision here.
One is that browning tends to ‘seal’ the meat and keep the flavour from being absorbed into the sauce. So, if you don’t brown, you’ll have rich, meaty sauce, but less flavorful meatballs.
The second factor is that browning would tend to help the meatball stay together.
So, if you want great meatballs, I’d tend to recommend browning. If you want a good sauce that happens to have some meatballs in it, (or pieces of meatball,) - there may be something to the no-brown approach. 
I can only provide my own experience. My Nana made the absolute best spaghetti and meatballs, and dropped the raw meatballs directly in the sauce to cook. When I made the dish myself for the first time, I thought that browning would give the meatballs more flavor, so I did that. Unfortunately, I found that they turned out tougher and less flavorful. The next time, I tried following my Nana’s example and the results were mmmmmmmm. Mmmmm. I’ve dropped my raw meatballs directly into the simmering sauce since then, and they turn out so so delicious. Maybe it depends on the composition of the meatballs? Mine are composed of ground beef with salt, herbes de provence, minced garlic, and fennel seeds.
There are any number of experts who’ll tell you that the sear doesn’t seal meat, either to lock in juices or block out infiltration. I’ve heard it on Cook’s County on PBS in a number of episodes, on Alton Brown’s show Good Eats, and yelled at a contestant on Hell’s Kitchen by Gordon Ramsay.
The purpose to a sear (notice, they call it 'sear’ing meat not 'seal’ing meat) was always the Malliard reaction for flavor.
My meatballs are a combo of ground beef & ground pork + herbs, garlic & salt.
I admit I’ve never been completely happy with the texture of my meatballs, they’ve always seemed slightly coarse and I am hoping for a more tender meatball.
Sorry to double post. Separate thoughts, slow typist, 5 min limit, yadda yadda
A light browning was always the way mom did it. Lately, I’ve taken to browning them in the oven. Mom had done this years ago, to limit the fat in dad’s diet. Mom makes her meatballs with ground meat, parsley, pine nuts, chopped raisins, bread crumbs and olive oil. So there may be a reason she has to strain off the fat. She also insists on extra-lean ground beef, to avoid gristle and bone fragments (supposedly, I tell her she’s losing richness and flavor be avoiding fat,) so that’s another reason it may need the sear for flavor.
My mother learned to make meatballs from Italian prostitutes (no, I don’t mean the meatballs were made *out *of Italian prostitutes), and she never browned–she cooked the meatballs (for hours and hours) in the sauce. They were the best meatballs (and sauce) I have ever tasted, and one of my Italian boyfriends was impressed with her culinary skills: “she’s a Jew, where’d she learn to cook like that?”
Browning the meat does render some of the fat. I use a fatty beef (20-25%), ground pork, and ground veal. I make a buttermilk panade, add lightly sauteed onions and garlic, egg yolk, lots of fresh parsley and romano chese. Because of the fatty meat, I still get plenty of flavor in the gravy. I like to make mini-meatballs. Everyone here appreciates the bite size pieces.
Don’t say that about Giada 
She’s known as “Cleavage Girl” around the rainy household. But I would definitely watch a show called “Cooking with Italian Prostitutes.”
I brown them in the oven for 8 - 10 minutes – otherwise mine always fall apart.
I think I will try not browning this time.
Would it be weird to do half and half?
You need filler - breadcrumbs work, but I prefer tearing up a couple slices of high-quality white bread and soaking them in milk or buttermilk until they get mushy and form a paste. Think about 2 slices bread & a half cup of liquid for each pound of meat. Mash it up with a fork, add to meat/herb mixture, form meatballs. That’ll lighten 'em up.
And as to the OP, I brown them before adding them to sauce.
Sausages in casings, though, I don’t brown. I like to poach them whole in the tomato sauce. There’s something about the texture that I really like when done that way - they get soft and silky, really yummy.
Also, don’t overcook them. I brown my rather large meatballs and set them aside in the fridge for the next few hours, while the other meats braise in the sauce. About 20 minutes before serving, I return the meatballs to the sauce and let them finish cooking. They’re fall-apart tender.
Sorry - I do actually have filler - I make fresh breadcrumbs out of white bread and I use a little milk and egg as a binder.
I always brown my meatballs. It’s just a matter of taste and a little bit of texture. Browning them adds a layer of meaty savory flavor, it crisps up the outside a little bit, and it renders some of the the fat out. Not browning creates a different texture and flavor. It’s a matter of taste. For example, with stews, I always brown beef, but there’s a couple of delicate veal and chicken stews where I opt out of browning, because I don’t want that “brown” flavor in the final dish. As you suggest, try 'em both ways, and see what you like. There’s no “right” answer.