Food energy per 750ml bottle of red wine is 500 kilocalories plus or minus 20% These are sometimes referred to as Calories.
Scenario: you are a busy academic and you make it home at 7.30pm on a friday night with a bottle of red wine for your wife's dinner party. Unfortunately the bottle has sat in your car boot for most of the day and is resting at 10 degrees Celcius. There is not time before the guests arrive at 8pm to warm it by the central heating and you want to serve it at "mediterranean temperature" or 25C. It is a special bottle of wine that you want to demonstrate; the guests may bring their own bottles but you have not control over what...
So, it says on the bottle "contents 75cl" and your microwave oven says on the backplate "output power 650 watts". Being a good scientist you know that 1 watt-second is a Joule and there are 4.2 Joules per calorie and one calorie raises 1 gram or 1 ml of water by 1 degree C. BUT - you don't know the efficiency of the microwave oven in transferring output energy to the contents.
Since there are 750 grams of wine, each degree C warming takes 750 calories or 750*4.2 = 3150 Joules or 3150 watt-seconds, or if the microwave oven puts all its notional output power into the wine, 4.85 seconds of full-power microwaving. Thus to get from 10C to 25C you need to microwave for 72.69 seconds....
The wine bottle was emptied into a jug, and the contents put aside for later culinary attention. The bottle was backfilled with water at a measured temperature of 18.5 +/- 0.2 C from the cold tap. The cork was replaced and the bottle microwaved on full power for 60 seconds (+/- 0.5 second). The water was decanted back into a jug at room temperature and the temperature measured as 28.5 +/- 0.2C.
The wine bottle contents were measured at 750 +/- 10 ml and so the rise in temperature of 10 +/- 0.3 C represented a calorie intake of 7500 +/- 300 calories or 31500 +/- 1250 Joules. The power absorbed over the minute of microwaving was therefore 525 +/- 25 watts. The percentage error here is about 5%.
Ideally you should check your own microwave oven using this method. However we observe that the 525 watts is 81% of the notional output of the 650 watt oven. Of course, the oven is 10 years old and so this does not necessarily indicate the energy efficiency of transfer to the contents of the bottle.
Therefore, assuming a 525 watt oven you should microwave for 6 seconds per degree C rise in temperature that you want.
Of course there are some people who object to microwaving red wine in bottles. It is possible to theorise about why this might not be such a good idea, but personally, I shall now go and try my nicely-decanted red wine at 25C.