BEURRE BLANC curdled what to do?
So I made a lime-chardonnay beurre blanc and it came out wonderfully but I made it early so would pop it in the microwave ever so often. But I left it too early on the last nuking and now my sauce has curdled. The steps to make it, I reduced red onion with some chardonnay and lime juice until there were like 2 tablespoons of liquid then i slowly whisked in frozen butter on and off low heat. can i save this sauce or is it forever lime juice with butter on top?
Most emulsions like this one as well as hollandaise can be re-homogenized by heating the sauce and whisking in a tsp. or two of water - beware, do this only a few minutes before you plan to serve your sauce as it is only a matter of time until your over-fattened sauce will break again.
buerre blanc is an emulsion of fat and liquid which in itself is not a normal thing to do but to make a successful butter sauce it has to be done at the last minute.
The other option is to add a little heavy cream to your wine reduction and again reduce this a small amount then whisk in your butter.
The cream just helps it to emulsify for longer but temperature is always a factor
Also use chilled butter not frozen
You have now discovered why beurre blanc is kind of rare in restaurants. It is difficult to rescue, but here is how you might try:
1) add a tablespoon of the wine
2) heat over low flame and whisk continuously
3) mix cornstarch or potato starch with the liquid to make a slurry
4) as the sauce heats slowly, drizzle in small amounts of the slurry
5) make homage to your kitchen god
Please do not make beurre blanc, hollandaise, or bearanaise way in advance and expect to nuke it at the last minute. These must be prepared a la minute as close as possible to serving time; welcome to the wonderful world of restaurant service. Once you make a beurre blanc, you must maintain a constant temp of about 150 Fahrenheit, taking it on and off a pot of simmering (190 degree) water at frequent intervals. This way, you might get one hour of life before it goes south.