The amount of alcohol that remains in your dish is dependent on the manner and length of preparation. Typically, the alcohol in the wine evaporates while cooking and only the flavor remains.
The following table of alcohol remaining after food preparation is from the Agricultural Research Services of the USDA (1989).
|Boiling liquid, remove from heat||85%|
|Overnight storage (Open)||70%|
|Dishes that have been baked or simmered||Alcohol retained|
|After 15 minutes||40%|
|After 30 minutes||35%|
|After 1 hour||25%|
|After 1.5 hours||20%|
|After 2 hours||10%|
|After 2.5 hours||5%|
As an estimate;
½-¾ cup of wine = 2 tbsp. of wine reduction
For the best flavour, wine should be reduced slowly over low heat. This method takes more time and effort, but it will likely achieve a superior sauce because the flavour compounds present in the wine are better preserved.
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