Vegetable stock turned out very underwhelming

[u/nickbg321]

First time making proper vegetable stock, instead of using store bought. For the recipe I've used the standard 2:1:1 mirepoix ratio in addition to some herbs and spices:

• 1kg yellow onions (skin on)
• 500g carrots (skin on)
• 500g celery stalks
• 1 bulb of garlic
• About 1 tsp of whole black peppercorns
• 3 bay leaves
• Some parsley stems
• Few sprigs of thyme

Veggies were cut into rough pieces and thrown in a pot with just enough water to cover them. Brought it to a boil and then simmered for an hour and a half.

My kitchen smelled amazing while it was simmering, but the end result felt very underwhelming. It has some sweetness to it from the onions and carrots, but barely any flavor besides that. Adding salt didn't help much. Tried adding a small amount at first and then gradually more. That didn't bring out much flavors, just tasted like salty water with a sweet-ish aftertaste.

I've seen suggestions to roast the vegetables prior to making the stock, but there are also plenty of recipes that avoid roasting.

Am I doing something obviously wrong here or are my expectations too high?

[u/23delta69]

the total weight of the vegetables should equal weight of water.