The idea of a slow cooker meatball recipe seems like a good one at first. After all, how many meatball recipes have you read out there that tell you to simmer the meatballs for a good, long time in their bath of tomato sauce? Long-simmering leads to better flavor and more tender texture, right?
Not so fast. We're people of science here! We don't put stock in hearsay! To test out this idea, I cooked up a few batches of Daniel's exemplary Juicy and Tender Italian Meatballs, leaving out the gelled chicken stock as I was afraid it might be too much of a confounding factor in my testing. I also streamlined a couple of the steps and ingredients—after all, slow cooker recipes are meant to be minimal fuss. After broiling the meatballs and heating up the sauce, I transferred the sauce to a slow cooker set on low heat.
I then added my meatballs to the pot, removing them one at a time at 15 minute intervals from 15 minutes all the way to seven hours later. I also removed a tablespoon of sauce each time in order to gauge the effects of long cooking on its flavor. While slow-cookers vary, and there's no industry standard on what "high," "low," or "warm" mean, I monitored the temperature of my cooker and know that it held steady at between 185 and 190°F for the entire time. Once all the meatballs were removed, I refrigerated all of them overnight, then gently reheated them to 140°F before tasting in order to iron out any differences that their final temperature might have made.
What did I find after tasting the meatballs? Not only does extended cooking make a difference in how the meatballs taste, but it's a drastic one, and not in the right direction. Meatballs cooked for 15 to 45 minutes or so were still tender and moist with a smooth, almost custard-like texture that just melts in your mouth. Between one hour and four hours, the meatballs become increasingly tougher and dryer. By the time you're over the five-hour mark, the meatballs are dry and crumbly, having expelled a good chunk of their moisture to the pot of sauce:
Next I figured I'd go at a lower temperature: my slow cooker holds around 165°F when set to "warm." Even at this temperature, the meatballs ended up starting to dry at nearly the same time.
It's pretty clear that longer cooking does not benefit the meatballs in any way. Just like a sausage, a hamburger, or a steak, the hotter you get them and the longer you cook them, the more moisture they lose.
On the other hand, it was undeniable that the sauce got better and better as it cooked, both by reducing and by picking up flavor from the meatballs as they simmered.
So what's a cook to do? Cook the meatballs for a short time in the sauce and you've got excellent balls but sub-par sauce. The other way around and you've got great sauce and meatballs that are tough as balls.
The solution turned out to be similar to what I did for my meatball pizza: flavor the sauce with some of the meat mixture before you form it into balls.
By sautéing the mixture in some olive oil, then adding an onion, garlic, oregano, and red pepper flakes, I created a really flavorful base for my tomatoes. What's more, once the sauce was in the slow cooker, it continued to reduce, the flavors of the meat and tomatoes exchanging.
So how does it all break down? Well, the night before (or the morning of) the day I want to eat my meal, I make my meatball mixture, form the meatballs, and construct the sauce. When I'm ready to go, I let the sauce cook for anywhere between seven to 10 hours at low heat (perfect for when you get home from work). When I want to serve the meatballs, I just drop the refrigerated meatballs into the sauce (you can broil them prior to refrigerating if you want a bit more browned flavor, or just drop them in completely raw) and let them cook through for about 30 minutes.
You end up with meatballs that are as tender as any you've ever had, with a sauce that's rich and thick, packed with intense meaty flavor. Finally, a slow cooker meatball that actually lives up to its imagined ideal.