Red wine butter mousse, or how to reheat butter-mounted sauces?

[demo]

AKA cooking by accident.

I had leftover red wine sauce, made from glaced onions reduced with stock and wine, reduced a lot, and mounted with butter, a lot of butter. In the fridge it looked like red butter. I heated it in a pan, I whisked on low heat, but the sauce broke.

"Let's start again", so i started to cool it down, I put the pan in a larger pan with cold water, and whisked quite heavily to speed up the cooling. Suddenly I was had lovely red wine butter mousse/chantilly. I served it with duck breast, a bit unfamiliar in the beginning, but very good.

What should I have done to reheat the sauce successfully? (And is there a name for what I made?)

[Baselerd]

You can always add an emulsifier to prevent the sauce from breaking. I think even xanthan gum can go a long ways to help.

[mkayahara]

The original sauce sounds more or less like a beurre rouge (that is, the red-wine version of a beurre blanc), which I think it pretty widely assumed to be unreheatable without some magic powders; Modernist Cuisine at Home recommends a combination of xanthan gum and liquid soy lecithin. As for your mousse, I think I would just call it a flavoured whipped butter!

[sigma]

Cut it into pieces, bring a tablespoon of water to a boil and whisk it into the hot water.

[demo]

Cut it into pieces, bring a tablespoon of water to a boil and whisk it into the hot water.

Yes, this was what I planned on doing, make a new sauce with the old one as the "butter".

I haven't thought of it as similar to buerre blanc, there is more liquid left before mounting in this red version of mine, but perheps not enough to make a sigificant difference.

I the future it will be either red wine flavoured whipped butter, or modern emulsifiers for the reheat. Will I have to have the emulsifiers in before I cool it the first time, or will I be able to whisk it in as I reheat?