How to fix a broken pan sauce?

I made a roast chicken last night, and like I always do I made a pan sauce from the browned vegetable bits and drippings at the bottom of the pan. I did what I normally do: poured off all but a tablespoon or so of fat, set in on medium high heat, added 1/4 cup dry vermouth and cooked that until very reduced, about 5 minutes, then added 3/4 cup of stock (one thing I did differently last night was subbed 1/4 of the stock for unfiltered apple juice, but I wouldn't think that would matter), let that reduce by half, about another 7 minutes, and then added two tablespoons butter and 1 teaspoon cornstarch and whisked it until it looked emulsified and satin-y, then turned off the heat. The sauce that had been incorporated then just fell apart, and separated in the most spectacular fashion I've ever seen. Just a pile of oil and browned solids, it was super depressing. The only thing, other than the apple juice, that was different from previous times is that my heat may have been a little higher throughout the process. So, my question is twofold: 1) what caused my sauce break? and 2) is there any way to repair it once it's broken?



702551 March 18, 2016
I don't know what kind of stock you were using, but it makes a difference. A well-made stock has a fair amount of gelatin in it, which helps the emulsification process. A superb stock will actually gel when refrigerated. The latter is what you really want to emulsify a pan sauce.

I don't follow a very rigorous process when I make stock so some batches are better than others.

Apple juice has no such gelatin. This may have been the critical difference but it's impossible to say for sure. Of course, a guy like Kenji would separate the drippings in half just before the stage of adding the stock (or apple juice) and proceed with the two different ingredients.

Kenji himself advises adding gelatin to help pan sauces. More details here:
702551 March 18, 2016
Just to clarify, Kenji would separate the drippings in half if he were conducting an experiment to determine the efficacy of chicken stock versus apple juice in emulsifying a pan sauce. That would be the scientific methodology of figuring out whether the apple juice was the culprit.
wenderzz March 18, 2016
I used homemade stock, and it has a fair amount of gelatin in it, to the point it gets a little thicker and wobbly in the fridge but doesn't gel (i've only had one stock that I made gel, and was totally frightened when it happened because I didn't realize it was a good thing).
702551 March 18, 2016
Looking at your original post, I see you only substituted a quarter of the stock with apple juice. I don't think that would be enough to matter, but I've never made pan sauce with apple juice.

Voted the Best Reply!

wenderzz March 18, 2016
If I were conducting an experiment versus cooking a weeknight meal for my family after a 10 hour day, I would for sure split the drippings and proceed with the two ingredients. Just busting your chops. Reading the article Lamb Chops posted, I bet the apple juice was the culprit. Since it's acidic, I should have probably added it with the vermouth to reduce it longer, and then added the stock and proceeded as normal. My next roast chicken will serve as part 2 of my Food Lab style experiment...
sexyLAMBCHOPx March 18, 2016
This article from Food52 may help. Also, search broken sauce in past hotline questions.
wenderzz March 18, 2016
Thank you! I had looked in previous hotlines but that article is a lifesaver!
wenderzz March 18, 2016
For added info, I dusted my butter with the cornstarch Kenji Lopez style, rather than make a slurry.
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