hot sauce or horse radish

I made beef stew over the weekend, and am always sure to add turnips and about a cup (or more to taste) of red wine. The red wine gives it a more complex taste and might be just the thing you are looking for.

I had this at a friend's house once who is Irish and they used Guinness. Its a very simple stew but was packed with flavor. I also heard adding red wine to a stew can boost the flavor as well as fresh herbs.

http://www.epicurious.com/recipes/food/views/Swedish-Sailors-Beef-Stew-107752

silver palate's beef carbonnade. so tasty! it's made with dark beer and plenty of onions...

Add fresh thyme, Worcestershire, a few tablespoons of tomato paste and marrow bones and that should give your stew a lot more character. Also, I brown off the carrots and potatoes in butter before adding them.

Try a Pot-au-feu recipe. It adds in Bacon, uses cheap and stew-perfect cuts of meat, plus you get the velvety and beefy goodness of marrow bones. You don't even need to serve it in the classic french way with cornichons and ... something else I always ignore.
The recipe in the archive on this site is fantastic, and really kicks beef stew up a notch.

Here's the link, and there is no need to slow cooker this puppy. Stove top on low for hours will work just fine!

http://www.thekitchn.com/thekitchn/recipe-review/slow-cooker-recipe-pot-au-feu-068620

Bay leaves!!! Oh, and worcestershire sauce is a good idea too...

shirley corriher's recipe for pot roast uses a handful of gingersnaps. i love it -- it's the perfect thickener and adds a mysterious "what IS that?" wonderful flavor.

Beer. Something dark.

I use the template from The Joy of Cooking, which involves dredging the stew meat in flour, S&P and browning it. Remove the meat and cook a mirepoix (written about recently on this site, BTW), then I dump in my seasonings (bay, tyhme are my preferences) and meat, loads of veggies (including more celery/carrots/onions), beef broth and beer (I don't like wine in stew unless it Coq au Vin. After it's simmered for hours into the fridge it goes, not to be eaten for at least a day, better at 2 days. When reheating, add a little extra broth and beer if needed.

Joining the chorus and putting in another vote for tomato paste (concentrated flavors), red wine, and bay leaves! Veggies and herbs alone seem unable to turn a soup into a proper, thick, lovely stew.

Use your regular recipe, but throw in a cup of Guinness along with the beef broth, some fresh thyme, a little Worcestershire sauce, and a couple of teaspoons of chopped brined green peppercorns. Yum!!

Vegetable juice instead of water, salt, worchestershire sauce, and plenty of freshly ground pepper.

I know this breaks the "really thorough browning of the meat" rule but the stew we like most is an oven beef stew which requires no browning, is thickened with tapioca, and is baked slowly for hours. The meat comes out tender.

Brown everything before stewing.
Potatoes, carrots celery, parsnips, turnips, Rutabega- Divide them up into small batches and brown well in butter or flour.
Don't overload your pan as you brown things- you want to brown them quickly. Build up a nice golden to dark brown crust on several sides without letting them cook too deeply.

Dredge your meat in seasoned four (Salt pepper parsley and garlic at a minimum.) and brown well- again don't overload the pan.

Deglaze the pan with wine, beer or stock and then start stewing. Reserve some of the vegetables and slow roast them if you have time and oven space- caramelize them well and save until the stew is nearly done.

Before serving, taste your stew and add seasoning as needed. If it needs more flavor and could use some salt punch it up by adding a spoonful or two of concentrated beef, chicken or vegetarian base. (These concentrated pastes beat bouillon cubes hands-down. Try different brands until you find one that you like best.)

To thicken blend roasted vegetables with a bit of the liquid and then add the paste to the pot. The roasted veg adds even more richness and sweetness to the stew.
Sift in flour gradually while stirring if even more thickening power is needed.

I just made a beef stew yesterday for a family dinner of 18...and it was a HUGE success. I thoroughly brown the meat with S&P, flour, a whole onion. Then I added lots of minced garlic, fresh parley, rosemary, thyme, a cup (or 2) of red wine, a can of whole tomatoes, beef bouillion, carrots, celery, potatoes and pearl onions. It was positively delicious.

I'll have my whole recipe on my website by tonight:
www.seejencook.blogspot.com

Happy stewing! :)

EDIT- '...brown well in butter or olive oil.'

Not sure how flour ended up there. I must need another cup of tea.

America's Test Kitchen recently did a Beef & Vegetable Soup that looked excellent. Yes, it's not stew, but what they did to kick up the taste profile could easily be translated to stew.

http://americastestkitchen.com/recipe.asp?recipeids=4518&iSeason=9

Cook's Illustrated published a beef stew recipe in their January 1996 recipe that I use to this day. Some key ingredients are red wine, chicken (yes, chicken) stock, thyme and bay leaves. A bit of flour added before the stock thickens the "gravy". Incredibly rich and satisfying.

I think the key if you are using herbs in your stew is to add dry in the beginning and fresh at the last few moments. If you add fresh herbs in the beginning all the flavor will be cooked out of them! This is especially true if you are using a crock pot. I like to use both fresh and dry. I find it adds depth of flavor.

I also agree that using a flavorful liquid helps. Beer, wine, and broth all make a better stew than plain water.

Add me in for the "something interesting in your broth." BBQ sauce, worcestshire sauce, beer, red wine, etc... And tomato paste always helps, whether it's chili, pasta, or stew.

Julia Child's Boeuf Bourguignon recipe is an ode to the joy of delicious beef stew -- her recipe provides the technique too (e.g., making sure the meat is perfectly dry, or else it won't brown, etc.).

http://knopfdoubleday.com/marketing/cooking/BoeufBourguignon.pdf

I think I poached this from a recipe somewhere, but I can't recall where:

White wine, thyme & a ton of grainy mustard makes a killer beef stew.

Plenty of red wine and plenty of garlic. Bay leaf.

I second the plenty of salt. I find that I really undersalt things if I don't taste them first. I think people sometimes forget that salt is not only about adding the salty flavor, it also enhances other flavors.

Also, tomato paste, browning the meat in a good dose of olive oil (adds nice fat if you're not using pre-made broth) and a hefty pinch of garlic salt adds a little kick, too.

You could also try caramelizing onions & carrots/parsnips/sweet root veggies).

Good luck!

I love America's Test Kitchen's cookbook and their beef stew recipe is my standard. Instead of adding potatoes to the stew, I make mash potatoes instead and dump the beef stew over it. It's so good.

Fish sauce!

Red wine, balsamic vinegar, and tomato paste!

A little balsamic vinegar really brightens up the flavors.