One of the techniques I’ve been wanting to try from Modernist Cuisine is pressure-cooked stock. The first time I heard that pressure-cooking was a viable option for stocks was in a post on Cooking Issues (followed up a couple of months later by another post). It wasn’t until I got Modernist Cuisine that the other benefits of pressure cookers convinced me to buy one. But it was stock that convinced me to buy the type of pressure cooker I bought.

The mental stumbling block I always had with pressure-cooked stocks was that they cook at a higher temperature than traditional stock. When you learn to make stock, the first lesson is always: “Never let it boil.” Surely raising the boiling point didn’t change that fact!

What I eventually learned is that the contents of a pressure cooker don’t actually boil while under pressure. As Modernist Cuisine explains, boiling happens when a liquid’s vapour pressure exceeds the ambient pressure around it. In a pressure cooker, as the vapour pressure rises, the ambient pressure does, too. So you never reach that point, and the liquid never boils.

What the Cooking Issues tests showed, though, was that you need a specific type of pressure cooker to produce an excellent stock: a non-venting pressure cooker, like the Kuhn Rikon I ended up buying, though it’s unclear why this is the case.

For my first attempt at pressure-cooked stock, I decided to make the fundamental stock in my kitchen: white chicken stock. (I know high-end restaurant books all say that veal stock is the fundamental stock, but sourcing veal bones is tough for the home cook.) In fact, I’ve been completely out of chicken stock for a few weeks now, so I needed to make a fairly significant volume. Considering the cost, I decided not to use the ratio of bones to meat to aromatics that Modernist Cuisine recommends; instead, I took a mix of chicken backs, wings and bones from whole chickens that I had butchered, and added a whole spent laying hen, all chopped up into smallish pieces and blanched. Then I added a bunch of onions, carrots, leeks and garlic (all finely sliced for optimum flavour extraction) and some parsley and black peppercorns. It was time to see what the pressure-cooker could do!