Roasting vegetables instead of sweating for a stock

Question

I'm about to cook some fish stock and was wondering whether the following technique is acceptable for home cooking, i.e. when I don't need the clearest stock and its only use going to be in simple soups.

I have one of these pressure cookers with an "air fryer" lid. I was wondering whether I will be doing the stock a disservice by roasting (baking?) carrots and onions alongside fish parts instead of sweating.

My reasoning is:

• Roast-y taste in vegetables and fish is a plus
• No added oil is a plus
• Convenience is a plus
• The pressure cooking will draw out aromatics just fine on its own

If that's acceptable, what cut, temp and duration would be a good start? I was thinking larger (than for sweating) chunks, 400F and 15 minutes.

Answer 1

I am not familiar with your particular device, but roasting ingredients for a stock is always a good idea if you are looking for those deeper, roasty flavors. Using a pressure cooker for stocks is also a good move. It is a big time saver. 400 is fine for roasting temp. Time will be dependent on how deeply roasted you want your ingredients. Fish stock generally takes less time than other proteins. You can have an excellent result pressure cooking fish stock at maximum pressure for 10 minutes.

Answer 2

It depends just a little bit on what you want. Fish stock for aspics or clear soup (well, I guess mildly turbid soup here) ideally has quite a light, sweet taste, and caramelised vegetables might throw that off. But for a heartier bouillabaisse or something, it would work quite well.

As for time/temp, I air fry vegetables at 200ºC for 8-12 minutes until more than slightly blackened, but I add the onions 4 minutes into that time. Cut will determine sweetness versus roastiness. Start at 5mm slices and see how you feel about them.

Answer 3

It’s more about surface area than overall chunk size for the roasted flavors. So you can cut slabs to roast to get a lot of surface area, if you’re just trying to transfer the flavor and then straining it. If you want vegetable chunks in the finished soup, you can always have two batches, one for flavoring that gets removed, then another batch that gets put in just before serving.

But you want a dry heat… you keep saying pressure cooker, but it’s the air fryer function that’s important; a pressure cooker would be moist heat and wouldn’t develop the roasted flavors.

As for the time and temperature, it’s so dependent on what you’re cooking, how tightly you have it packed, etc, that you likely need to run a test batch and check regularly. I would go for 450°F in a non-fan oven, but 400°F in a fan oven/air fryer is probably equivalent. Too hot and you risk missing the window of brown and delicious to burned, and too cool just means that it takes forever.