Question on pressure cooked chicken stock

dr.kiuchi

I'm reposting here for more visibility, and hopefully some responses, so thanks in advance!

For the recipe listed here on chefsteps.

Two questions:  

1. The recipe description states that the stock comes out clearer due to the water never coming to a boil inside the pressure cooker. However in step 6, it explicitly calls out for the water to come to a boil before closing the lid on the cooker. Should this be the proper technique?

2. The yield shown in the recipe for the actual stock is 3000g. The water put into the recipe is also 3000g. Basically stating that there is 0% water loss. How does one account for the steam being let off by the pressure cooker during the 90 minute time frame?

I ask because I followed the recipe, although scaled. My yield was roughly under 1/2 of the original amount of water that I had put in, and turned out quite dark. I'm wondering what I did wrong. Additionally when I put the water in step 5, it did not cover the bones / vegetables, which is something I am not used to.

Chris_Young_80640

That's a bit of a mis-statement in step 6, we generally put the lid on just as the pot is reaching a simmer. Definitely do not let it come to a rolling boil.

You are losing very little water from steam. One cc of liquid water expands to 1680 cc of steam, so although it might seem like a lot of steam escaping, that is actually very little liquid water. Plus you are going to gain some water from ingredients that break down during cooking.

If you lost nearly have of your original liquid volume, I think you are running your pressure cooker at far too high a heat. Steam should barely be escaping, if it's billowing out than you're over-pressurizing the cooker. Just turn the heat down next time.