Self-clarifying stocks

[Jonathan Day]

First, many thanks for joining this Q&A. I've read both of your "chef" books and have enjoyed them a lot, not just for the food but also for some fine writing. It is great that you've come to visit eGullet.

In The Making of a Chef, Chef Pardus describes a new way to make stock:

I'm going to start with some boiling water, the chef said, and we're going to add some acid. We're going to save all our tomato scraps from today and we're going to add it to our white stock. We're going to try to make a self-clarifying stock. It's apparently a technique they've been using in Europe ... we don't teach it here at the CIA, but you can do it and it works pretty well."

Ever since reading that rather elliptical description, I've experimented, trying to make a stock that clarifies itself as it cooks. My most successful effort so far was a chicken stock; I used a lot of tomato skins and scraps and simmered it very, very slowly for a long time, checking the stock for clarity and body after 2, 3, 4, hours.

It came up clear but rose-coloured, and with too much of a tomato flavour.

What's the secret? How do you make a stock that clarifies itself as it cooks? Please enlighten us.

[Michael Ruhlman]

I'd forgotten about that until just recently. I find that if you cook a stock so that there are no bubbles rising to the surface but the pot is too hot to hold your hands against, that's a good temperature. And that easy easy cook (in the oven at 170-180 degrees) results in a very clear stock. A stock becomes cloudy if you simmer it too hard and emulsify the fat into the stock. Trying boiling chicken bones and scraps really hard for an hour. It will look almost creamy. The idea you mention is one of adding enough acid to a stock to denature enough proteins to trap the impurities that cloud a stock. As you make a consomme raft with protein (egg white) and acid and for flavor aromats. Have you made a consomme? You should try that if you haven't already so you get a good visual picture of a clarification and a perfectly clear liquid.